A couple fixes

src/symbols/symbols_with_libdwarf.cpp

@@ -120,13 +120,13 @@ namespace libdwarf {
                 int
             >::type = 0
         >
-        int wrap(int (*f)(Args...), Args2&&... args) const {
+        Result<int, internal_error> wrap(int (*f)(Args...), Args2&&... args) const {
             Dwarf_Error error = nullptr;
             int ret = f(std::forward<Args2>(args)..., &error);
             if(ret == DW_DLV_ERROR) {
-                handle_dwarf_error(dbg, error);
+                return handle_dwarf_error(dbg, error);
             }
-            return ret;
+            return Ok(ret);
         }
 
     public:
@@ -178,14 +178,17 @@ namespace libdwarf {
                 nullptr,
                 &dbg
             );
-            if(ret == DW_DLV_OK) {
+            if(!ret) {
+                ret.drop_error();
+                ok = false;
+            } else if(ret.unwrap_value() == DW_DLV_OK) {
                 ok = true;
-            } else if(ret == DW_DLV_NO_ENTRY) {
+            } else if(ret.unwrap_value() == DW_DLV_NO_ENTRY) {
                 // fail, no debug info
                 ok = false;
             } else {
                 ok = false;
-                PANIC("Unknown return code from dwarf_init_path");
+                ASSERT(false, "Unknown return code from dwarf_init_path");
             }
 
             if(ok) {
@@ -256,7 +259,7 @@ namespace libdwarf {
             Dwarf_Unsigned next_cu_header;
             Dwarf_Half header_cu_type;
             while(true) {
-                int ret = wrap(
+                auto ret = wrap(
                     dwarf_next_cu_header_d,
                     dbg,
                     true,
@@ -271,20 +274,29 @@ namespace libdwarf {
                     &next_cu_header,
                     &header_cu_type
                 );
-                if(ret == DW_DLV_NO_ENTRY) {
+                if(!ret) {
+                    ret.drop_error();
+                    return;
+                }
+                if(ret.unwrap_value() == DW_DLV_NO_ENTRY) {
                     if(dump_dwarf) {
                         std::fprintf(stderr, "End walk_dbg\n");
                     }
                     return;
                 }
-                if(ret != DW_DLV_OK) {
-                    PANIC("Unexpected return code from dwarf_next_cu_header_d");
+                if(ret.unwrap_value() != DW_DLV_OK) {
+                    ASSERT(false, "Unexpected return code from dwarf_next_cu_header_d");
                     return;
                 }
                 // 0 passed as the die to the first call of dwarf_siblingof_b immediately after dwarf_next_cu_header_d
                 // to fetch the cu die
                 die_object cu_die(dbg, nullptr);
-                cu_die = cu_die.get_sibling();
+                auto sibling = cu_die.get_sibling();
+                if(sibling.is_error()) {
+                    sibling.drop_error();
+                    break;
+                }
+                cu_die = std::move(sibling).unwrap_value();
                 if(!cu_die) {
                     break;
                 }
@@ -304,8 +316,17 @@ namespace libdwarf {
                     Dwarf_Half dwversion = 0;
                     dwarf_get_version_of_die(cu_die.get(), &dwversion, &offset_size);
                     auto ranges_vec = cu_die.get_rangelist_entries(dwversion);
-                    for(auto range : ranges_vec) {
-                        cu_cache.push_back({ cu_die.clone(), dwversion, range.first, range.second });
+                    if(!ranges_vec) {
+                        ranges_vec.drop_error();
+                        return true;
+                    }
+                    for(auto range : ranges_vec.unwrap_value()) {
+                        auto cu = cu_die.clone();
+                        if(!cu) {
+                            ranges_vec.drop_error();
+                            return true;
+                        }
+                        cu_cache.push_back({std::move(cu).unwrap_value(), dwversion, range.low, range.high});
                     }
                     return true;
                 });
@@ -316,52 +337,75 @@ namespace libdwarf {
             }
         }
 
-        std::string subprogram_symbol(
+        Result<std::string, internal_error> subprogram_symbol(
             const die_object& die,
             Dwarf_Half dwversion
         ) {
-            ASSERT(die.get_tag() == DW_TAG_subprogram || die.get_tag() == DW_TAG_inlined_subroutine);
+            auto tag = die.get_tag();
+            ASSERT(tag && (tag.unwrap_value() == DW_TAG_subprogram || tag.unwrap_value() == DW_TAG_inlined_subroutine));
             optional<std::string> name;
-            if(auto linkage_name = die.get_string_attribute(DW_AT_linkage_name)) {
-                name = std::move(linkage_name);
-            } else if(auto linkage_name = die.get_string_attribute(DW_AT_MIPS_linkage_name)) {
-                name = std::move(linkage_name);
-            } else if(auto linkage_name = die.get_string_attribute(DW_AT_name)) {
-                name = std::move(linkage_name);
+            auto linkage_name = die.get_string_attribute(DW_AT_linkage_name);
+            if(!linkage_name) {
+                linkage_name.drop_error();
+            }
+            if(linkage_name.has_value() && linkage_name.unwrap_value()) {
+                name = std::move(linkage_name).unwrap_value();
+            } {
+                auto linkage_name = die.get_string_attribute(DW_AT_MIPS_linkage_name);
+                if(!linkage_name) {
+                    linkage_name.drop_error();
+                }
+                if(linkage_name.has_value() && linkage_name.unwrap_value()) {
+                    name = std::move(linkage_name).unwrap_value();
+                } else {
+                    auto linkage_name = die.get_string_attribute(DW_AT_name);
+                    if(!linkage_name) {
+                        linkage_name.drop_error();
+                    }
+                    if(linkage_name.has_value() && linkage_name.unwrap_value()) {
+                        name = std::move(linkage_name).unwrap_value();
+                    }
+                }
             }
             if(name.has_value()) {
                 return std::move(name).unwrap();
             } else {
                 if(die.has_attr(DW_AT_specification)) {
-                    die_object spec = die.resolve_reference_attribute(DW_AT_specification);
-                    return subprogram_symbol(spec, dwversion);
+                    auto spec = die.resolve_reference_attribute(DW_AT_specification);
+                    if(!spec) {
+                        return std::move(spec).unwrap_error();
+                    }
+                    return subprogram_symbol(std::move(spec).unwrap_value(), dwversion);
                 } else if(die.has_attr(DW_AT_abstract_origin)) {
-                    die_object spec = die.resolve_reference_attribute(DW_AT_abstract_origin);
-                    return subprogram_symbol(spec, dwversion);
+                    auto spec = die.resolve_reference_attribute(DW_AT_abstract_origin);
+                    if(!spec) {
+                        return std::move(spec).unwrap_error();
+                    }
+                    return subprogram_symbol(std::move(spec).unwrap_value(), dwversion);
                 }
             }
-            return "";
+            return Ok("");
         }
 
         // despite (some) dwarf using 1-indexing, file_i should be the 0-based index
-        std::string resolve_filename(const die_object& cu_die, Dwarf_Unsigned file_i) {
+        Result<std::string, internal_error> resolve_filename(const die_object& cu_die, Dwarf_Unsigned file_i) {
             std::string filename;
             if(get_cache_mode() == cache_mode::prioritize_memory) {
                 char** dw_srcfiles;
                 Dwarf_Signed dw_filecount;
-                VERIFY(wrap(dwarf_srcfiles, cu_die.get(), &dw_srcfiles, &dw_filecount) == DW_DLV_OK);
+                CHECK_OK(wrap(dwarf_srcfiles, cu_die.get(), &dw_srcfiles, &dw_filecount));
                 if(Dwarf_Signed(file_i) < dw_filecount) {
                     // dwarf is using 1-indexing
                     filename = dw_srcfiles[file_i];
                 }
                 dwarf_dealloc(cu_die.dbg, dw_srcfiles, DW_DLA_LIST);
             } else {
-                auto off = cu_die.get_global_offset();
+                PROP_ASSIGN(off, cu_die.get_global_offset());
                 auto it = srcfiles_cache.find(off);
                 if(it == srcfiles_cache.end()) {
                     char** dw_srcfiles;
                     Dwarf_Signed dw_filecount;
-                    VERIFY(wrap(dwarf_srcfiles, cu_die.get(), &dw_srcfiles, &dw_filecount) == DW_DLV_OK);
+                    CHECK_OK(wrap(dwarf_srcfiles, cu_die.get(), &dw_srcfiles, &dw_filecount));
                     it = srcfiles_cache.insert(it, {off, {dw_srcfiles, dw_filecount}});
                 }
                 char** dw_srcfiles = it->second.first;
@@ -381,7 +425,8 @@ namespace libdwarf {
             Dwarf_Half dwversion,
             std::vector<stacktrace_frame>& inlines
         ) {
-            ASSERT(die.get_tag() == DW_TAG_subprogram || die.get_tag() == DW_TAG_inlined_subroutine);
+            auto tag = die.get_tag();
+            ASSERT(tag && (tag.unwrap_value() == DW_TAG_subprogram || tag.unwrap_value() == DW_TAG_inlined_subroutine));
             // get_inlines_info is recursive and recurses into dies with pc ranges matching the pc we're looking for,
             // however, because I wouldn't want anything stack overflowing I'm breaking the recursion out into a loop
             // while looping when we find the target die we need to be able to store a die somewhere that doesn't die
@@ -390,47 +435,70 @@ namespace libdwarf {
             optional<std::reference_wrapper<const die_object>> current_die = die;
             while(current_die.has_value()) {
                 auto child = current_die.unwrap().get().get_child();
-                if(!child) {
+                if(!child.has_value() || !child.unwrap_value()) {
                     break;
                 }
                 optional<std::reference_wrapper<const die_object>> target_die;
                 walk_die_list(
-                    child,
+                    child.unwrap_value(),
                     [this, &cu_die, pc, dwversion, &inlines, &target_die, &current_obj_holder] (const die_object& die) {
-                        if(die.get_tag() == DW_TAG_inlined_subroutine && die.pc_in_die(dwversion, pc)) {
+                        auto tag = die.get_tag();
+                        if(!tag) {
+                            tag.drop_error();
+                            return true;
+                        }
+                        if(tag.unwrap_value() == DW_TAG_inlined_subroutine && die.pc_in_die(dwversion, pc)) {
                             const auto name = subprogram_symbol(die, dwversion);
-                            auto file_i = die.get_unsigned_attribute(DW_AT_call_file);
+                            auto file_i_r = die.get_unsigned_attribute(DW_AT_call_file);
+                            if(!file_i_r) {
+                                file_i_r.drop_error();
+                                return true;
+                            }
+                            auto file_i = std::move(file_i_r).unwrap_value();
                             if(file_i) {
                                 // for dwarf 2, 3, 4, and experimental line table version 0xfe06 1-indexing is used
                                 // for dwarf 5 0-indexing is used
                                 auto line_table_opt = get_line_table(cu_die);
-                                if(line_table_opt) {
-                                    auto& line_table = line_table_opt.unwrap().get();
-                                    if(line_table.version != 5) {
-                                        if(file_i.unwrap() == 0) {
-                                            file_i.reset(); // 0 means no name to be found
-                                        } else {
-                                            // decrement to 0-based index
-                                            file_i.unwrap()--;
-                                        }
+                                if(!line_table_opt) {
+                                    line_table_opt.drop_error();
+                                    return true;
+                                }
+                                auto& line_table = line_table_opt.unwrap_value().get();
+                                if(line_table.version != 5) {
+                                    if(file_i.unwrap() == 0) {
+                                        file_i.reset(); // 0 means no name to be found
+                                    } else {
+                                        // decrement to 0-based index
+                                        file_i.unwrap()--;
                                     }
-                                } else {
-                                    // silently continue
                                 }
                             }
-                            std::string file = file_i ? resolve_filename(cu_die, file_i.unwrap()) : "";
+                            std::string file = file_i ? resolve_filename(cu_die, file_i.unwrap()).value_or("") : "";
                             const auto line = die.get_unsigned_attribute(DW_AT_call_line);
+                            if(!line) {
+                                line.drop_error();
+                                return true;
+                            }
                             const auto col = die.get_unsigned_attribute(DW_AT_call_column);
+                            if(!col) {
+                                col.drop_error();
+                                return true;
+                            }
                             inlines.push_back(stacktrace_frame{
                                 0,
                                 0, // TODO: Could put an object address here...
-                                {static_cast<std::uint32_t>(line.value_or(0))},
-                                {static_cast<std::uint32_t>(col.value_or(0))},
+                                {static_cast<std::uint32_t>(line.unwrap_value().value_or(0))},
+                                {static_cast<std::uint32_t>(col.unwrap_value().value_or(0))},
                                 file,
-                                name,
+                                name.value_or(""),
                                 true
                             });
-                            current_obj_holder = die.clone();
+                            auto d = die.clone();
+                            if(!d) {
+                                d.drop_error();
+                                return false;
+                            }
+                            current_obj_holder = std::move(d).unwrap_value();
                             target_die = current_obj_holder;
                             return false;
                         } else {
@@ -443,15 +511,16 @@ namespace libdwarf {
             }
         }
 
-        std::string retrieve_symbol_for_subprogram(
+        Result<std::string, internal_error> retrieve_symbol_for_subprogram(
             const die_object& cu_die,
             const die_object& die,
             Dwarf_Addr pc,
             Dwarf_Half dwversion,
             std::vector<stacktrace_frame>& inlines
         ) {
-            ASSERT(die.get_tag() == DW_TAG_subprogram);
-            const auto name = subprogram_symbol(die, dwversion);
+            auto tag = die.get_tag();
+            ASSERT(tag && tag.unwrap_value() == DW_TAG_subprogram);
+            auto name = subprogram_symbol(die, dwversion);
             if(detail::should_resolve_inlined_calls()) {
                 get_inlines_info(cu_die, die, pc, dwversion, inlines);
             }
@@ -473,42 +542,52 @@ namespace libdwarf {
                 die,
                 [this, &cu_die, pc, dwversion, &frame, &inlines, &found] (const die_object& die) {
                     if(dump_dwarf) {
-                        std::fprintf(
-                            stderr,
-                            "-------------> %08llx %s %s\n",
-                            to_ull(die.get_global_offset()),
+                        microfmt::print(
+                            std::cerr,
+                            "-------------> {8:0h} {} {}\n",
+                            die.get_global_offset().value_or(0),
                             die.get_tag_name(),
-                            die.get_name().c_str()
+                            die.get_name().value_or("<error>")
                         );
                     }
-                    if(!(die.get_tag() == DW_TAG_namespace || die.pc_in_die(dwversion, pc))) {
+                    auto tag = die.get_tag();
+                    if(!tag) {
+                        tag.drop_error();
+                        return true;
+                    }
+                    if(!(tag.unwrap_value() == DW_TAG_namespace || die.pc_in_die(dwversion, pc))) {
                         if(dump_dwarf) {
-                            std::fprintf(stderr, "pc not in die\n");
+                            microfmt::print(std::cerr, "pc not in die\n");
                         }
                     } else {
                         if(trace_dwarf) {
-                            std::fprintf(
-                                stderr,
-                                "%s %08llx %s\n",
-                                die.get_tag() == DW_TAG_namespace ? "pc maybe in die (namespace)" : "pc in die",
-                                to_ull(die.get_global_offset()),
+                            microfmt::print(
+                                std::cerr,
+                                "{} {8:0h} {}\n",
+                                tag.unwrap_value() == DW_TAG_namespace ? "pc maybe in die (namespace)" : "pc in die",
+                                die.get_global_offset().value_or(0),
                                 die.get_tag_name()
                             );
                         }
-                        if(die.get_tag() == DW_TAG_subprogram) {
-                            frame.symbol = retrieve_symbol_for_subprogram(cu_die, die, pc, dwversion, inlines);
+                        if(tag.unwrap_value() == DW_TAG_subprogram) {
+                            frame.symbol = retrieve_symbol_for_subprogram(cu_die, die, pc, dwversion, inlines)
+                                .value_or("");
                             found = true;
                             return false;
                         }
                         auto child = die.get_child();
-                        if(child) {
-                            if(retrieve_symbol_walk(cu_die, child, pc, dwversion, frame, inlines)) {
+                        if(!child) {
+                            child.drop_error();
+                            return true;
+                        }
+                        if(child.unwrap_value()) {
+                            if(retrieve_symbol_walk(cu_die, child.unwrap_value(), pc, dwversion, frame, inlines)) {
                                 found = true;
                                 return false;
                             }
                         } else {
                             if(dump_dwarf) {
-                                std::fprintf(stderr, "(no child)\n");
+                                microfmt::print(std::cerr, "(no child)\n");
                             }
                         }
                     }
@@ -516,7 +595,7 @@ namespace libdwarf {
                 }
             );
             if(dump_dwarf) {
-                std::fprintf(stderr, "End walk_die_list\n");
+                microfmt::print(std::cerr, "End walk_die_list\n");
             }
             return found;
         }
@@ -530,20 +609,38 @@ namespace libdwarf {
             walk_die_list(
                 die,
                 [this, dwversion, &vec] (const die_object& die) {
-                    switch(die.get_tag()) {
+                    auto tag = die.get_tag();
+                    if(!tag) {
+                        tag.drop_error();
+                        return true;
+                    }
+                    switch(tag.unwrap_value()) {
                         case DW_TAG_subprogram:
                             {
                                 auto ranges_vec = die.get_rangelist_entries(dwversion);
+                                if(!ranges_vec) {
+                                    ranges_vec.drop_error();
+                                    return true;
+                                }
                                 // TODO: Feels super inefficient and some day should maybe use an interval tree.
-                                for(auto range : ranges_vec) {
-                                    vec.push_back({ die.clone(), range.first, range.second });
+                                for(auto range : ranges_vec.unwrap_value()) {
+                                    auto d = die.clone();
+                                    if(!d) {
+                                        d.drop_error();
+                                        return true;
+                                    }
+                                    vec.push_back({ std::move(d).unwrap_value(), range.low, range.high });
                                 }
                                 // Walk children to get things like lambdas
                                 // TODO: Somehow find a way to get better names here? For gcc it's just "operator()"
                                 // On clang it's better
                                 auto child = die.get_child();
-                                if(child) {
-                                    preprocess_subprograms(child, dwversion, vec);
+                                if(!child) {
+                                    child.drop_error();
+                                    return true;
+                                }
+                                if(child.unwrap_value()) {
+                                    preprocess_subprograms(child.unwrap_value(), dwversion, vec);
                                 }
                             }
                             break;
@@ -555,8 +652,12 @@ namespace libdwarf {
                         case DW_TAG_compile_unit:
                             {
                                 auto child = die.get_child();
-                                if(child) {
-                                    preprocess_subprograms(child, dwversion, vec);
+                                if(!child) {
+                                    child.drop_error();
+                                    return true;
+                                }
+                                if(child.unwrap_value()) {
+                                    preprocess_subprograms(child.unwrap_value(), dwversion, vec);
                                 }
                             }
                             break;
@@ -583,7 +684,10 @@ namespace libdwarf {
                 retrieve_symbol_walk(cu_die, cu_die, pc, dwversion, frame, inlines);
             } else {
                 auto off = cu_die.get_global_offset();
-                auto it = subprograms_cache.find(off);
+                if(!off) {
+                    return;
+                }
+                auto it = subprograms_cache.find(off.unwrap_value());
                 if(it == subprograms_cache.end()) {
                     // TODO: Refactor. Do the sort in the preprocess function and return the vec directly.
                     std::vector<subprogram_entry> vec;
@@ -591,8 +695,8 @@ namespace libdwarf {
                     std::sort(vec.begin(), vec.end(), [] (const subprogram_entry& a, const subprogram_entry& b) {
                         return a.low < b.low;
                     });
-                    subprograms_cache.emplace(off, std::move(vec));
-                    it = subprograms_cache.find(off);
+                    subprograms_cache.emplace(off.unwrap_value(), std::move(vec));
+                    it = subprograms_cache.find(off.unwrap_value());
                 }
                 auto& vec = it->second;
                 auto vec_it = first_less_than_or_equal(
@@ -607,7 +711,8 @@ namespace libdwarf {
                 if(vec_it != vec.end()) {
                     //vec_it->die.print();
                     if(vec_it->die.pc_in_die(dwversion, pc)) {
-                        frame.symbol = retrieve_symbol_for_subprogram(cu_die, vec_it->die, pc, dwversion, inlines);
+                        frame.symbol = retrieve_symbol_for_subprogram(cu_die, vec_it->die, pc, dwversion, inlines)
+                            .value_or("");
                     }
                 } else {
                     ASSERT(vec.size() == 0, "Vec should be empty?");
@@ -617,29 +722,35 @@ namespace libdwarf {
 
         // returns a reference to a CU's line table, may be invalidated if the line_tables map is modified
         CPPTRACE_FORCE_NO_INLINE_FOR_PROFILING
-        optional<std::reference_wrapper<line_table_info>> get_line_table(const die_object& cu_die) {
-            auto off = cu_die.get_global_offset();
+        Result<std::reference_wrapper<line_table_info>, internal_error> get_line_table(const die_object& cu_die) {
+            PROP_ASSIGN(off, cu_die.get_global_offset());
             auto it = line_tables.find(off);
             if(it != line_tables.end()) {
-                return it->second;
+                return std::reference_wrapper<line_table_info>{it->second};
             } else {
                 Dwarf_Unsigned version;
                 Dwarf_Small table_count;
                 Dwarf_Line_Context line_context;
-                int ret = wrap(
-                    dwarf_srclines_b,
-                    cu_die.get(),
-                    &version,
-                    &table_count,
-                    &line_context
+                PROP_ASSIGN(
+                    ret,
+                    wrap(
+                        dwarf_srclines_b,
+                        cu_die.get(),
+                        &version,
+                        &table_count,
+                        &line_context
+                    )
                 );
                 static_assert(std::is_unsigned<decltype(table_count)>::value, "Expected unsigned Dwarf_Small");
-                VERIFY(/*table_count >= 0 &&*/ table_count <= 2, "Unknown dwarf line table count");
-                if(ret == DW_DLV_NO_ENTRY) {
-                    // TODO: Failing silently for now
-                    return nullopt;
+                if(table_count > 2) {
+                    return internal_error("Unknown dwarf line table count");
+                }
+                if(ret == DW_DLV_NO_ENTRY) {
+                    return internal_error("dwarf_srclines_b DW_DLV_NO_ENTRY");
+                }
+                if(ret != DW_DLV_OK) {
+                    return internal_error("dwarf_srclines_b not ok");
                 }
-                VERIFY(ret == DW_DLV_OK);
 
                 std::vector<line_entry> line_entries;
 
@@ -649,7 +760,7 @@ namespace libdwarf {
                     Dwarf_Signed line_count = 0;
                     Dwarf_Line* linebuf_actuals = nullptr;
                     Dwarf_Signed linecount_actuals = 0;
-                    VERIFY(
+                    CHECK_OK(
                         wrap(
                             dwarf_srclines_two_level_from_linecontext,
                             line_context,
@@ -657,7 +768,7 @@ namespace libdwarf {
                             &line_count,
                             &linebuf_actuals,
                             &linecount_actuals
-                        ) == DW_DLV_OK
+                        )
                     );
 
                     // TODO: Make any attempt to note PC ranges? Handle line end sequence?
@@ -665,12 +776,12 @@ namespace libdwarf {
                     for(int i = 0; i < line_count; i++) {
                         Dwarf_Line line = line_buffer[i];
                         Dwarf_Addr low_addr = 0;
-                        VERIFY(wrap(dwarf_lineaddr, line, &low_addr) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_lineaddr, line, &low_addr));
                         // scan ahead for the last line entry matching this pc
                         int j;
                         for(j = i + 1; j < line_count; j++) {
                             Dwarf_Addr addr = 0;
-                            VERIFY(wrap(dwarf_lineaddr, line_buffer[j], &addr) == DW_DLV_OK);
+                            CHECK_OK(wrap(dwarf_lineaddr, line_buffer[j], &addr));
                             if(addr != low_addr) {
                                 break;
                             }
@@ -707,7 +818,7 @@ namespace libdwarf {
                 }
 
                 it = line_tables.insert({off, {version, line_context, std::move(line_entries)}}).first;
-                return it->second;
+                return std::reference_wrapper<line_table_info>{it->second};
             }
         }
 
@@ -719,9 +830,10 @@ namespace libdwarf {
         ) {
             auto table_info_opt = get_line_table(cu_die);
             if(!table_info_opt) {
-                return; // failing silently for now
+                table_info_opt.drop_error();
+                return;
             }
-            auto& table_info = table_info_opt.unwrap().get();
+            auto& table_info = table_info_opt.unwrap_value().get();
             if(get_cache_mode() == cache_mode::prioritize_speed) {
                 // Lookup in the table
                 auto& line_entries = table_info.line_entries;
@@ -739,21 +851,42 @@ namespace libdwarf {
                     // line number
                     if(!table_it->line_number) {
                         Dwarf_Unsigned line_number = 0;
-                        VERIFY(wrap(dwarf_lineno, line, &line_number) == DW_DLV_OK);
+                        auto res = wrap(dwarf_lineno, line, &line_number);
+                        if(!res) {
+                            res.drop_error();
+                            return;
+                        } else if(res.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         table_it->line_number = static_cast<std::uint32_t>(line_number);
                     }
                     frame.line = table_it->line_number.unwrap();
                     // column number
                     if(!table_it->column_number) {
                         Dwarf_Unsigned column_number = 0;
-                        VERIFY(wrap(dwarf_lineoff_b, line, &column_number) == DW_DLV_OK);
+                        auto res = wrap(dwarf_lineoff_b, line, &column_number);
+                        if(!res) {
+                            res.drop_error();
+                            return;
+                        } else if(res.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         table_it->column_number = static_cast<std::uint32_t>(column_number);
                     }
                     frame.column = table_it->column_number.unwrap();
                     // filename
                     if(!table_it->path) {
                         char* filename = nullptr;
-                        VERIFY(wrap(dwarf_linesrc, line, &filename) == DW_DLV_OK);
+                        auto res = wrap(dwarf_linesrc, line, &filename);
+                        if(!res) {
+                            res.drop_error();
+                            return;
+                        } else if(res.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         auto wrapper = raii_wrap(
                             filename,
                             [this] (char* str) { if(str) dwarf_dealloc(dbg, str, DW_DLA_STRING); }
@@ -769,22 +902,34 @@ namespace libdwarf {
                 Dwarf_Signed line_count = 0;
                 Dwarf_Line* linebuf_actuals = nullptr;
                 Dwarf_Signed linecount_actuals = 0;
-                VERIFY(
-                    wrap(
-                        dwarf_srclines_two_level_from_linecontext,
-                        line_context,
-                        &line_buffer,
-                        &line_count,
-                        &linebuf_actuals,
-                        &linecount_actuals
-                    ) == DW_DLV_OK
+                auto res = wrap(
+                    dwarf_srclines_two_level_from_linecontext,
+                    line_context,
+                    &line_buffer,
+                    &line_count,
+                    &linebuf_actuals,
+                    &linecount_actuals
                 );
+                if(!res) {
+                    res.drop_error();
+                    return;
+                } else if(res.unwrap_value() != DW_DLV_OK) {
+                    ASSERT(false, "dwarf call not ok");
+                    return;
+                }
                 Dwarf_Addr last_lineaddr = 0;
                 Dwarf_Line last_line = nullptr;
                 for(int i = 0; i < line_count; i++) {
                     Dwarf_Line line = line_buffer[i];
                     Dwarf_Addr lineaddr = 0;
-                    VERIFY(wrap(dwarf_lineaddr, line, &lineaddr) == DW_DLV_OK);
+                    auto res = wrap(dwarf_lineaddr, line, &lineaddr);
+                    if(!res) {
+                        res.drop_error();
+                        return;
+                    } else if(res.unwrap_value() != DW_DLV_OK) {
+                        ASSERT(false, "dwarf call not ok");
+                        return;
+                    }
                     Dwarf_Line found_line = nullptr;
                     if(pc == lineaddr) {
                         // Multiple PCs may correspond to a line, find the last one
@@ -792,7 +937,14 @@ namespace libdwarf {
                         for(int j = i + 1; j < line_count; j++) {
                             Dwarf_Line line = line_buffer[j];
                             Dwarf_Addr lineaddr = 0;
-                            VERIFY(wrap(dwarf_lineaddr, line, &lineaddr) == DW_DLV_OK);
+                            auto res = wrap(dwarf_lineaddr, line, &lineaddr);
+                            if(!res) {
+                            res.drop_error();
+                                return;
+                            } else if(res.unwrap_value() != DW_DLV_OK) {
+                                ASSERT(false, "dwarf call not ok");
+                                return;
+                            }
                             if(pc == lineaddr) {
                                 found_line = line;
                             }
@@ -803,10 +955,24 @@ namespace libdwarf {
                     }
                     if(found_line) {
                         Dwarf_Unsigned line_number = 0;
-                        VERIFY(wrap(dwarf_lineno, found_line, &line_number) == DW_DLV_OK);
+                        auto res = wrap(dwarf_lineno, found_line, &line_number);
+                        if(!res) {
+                            res.drop_error();
+                            return;
+                        } else if(res.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         frame.line = static_cast<std::uint32_t>(line_number);
                         char* filename = nullptr;
-                        VERIFY(wrap(dwarf_linesrc, found_line, &filename) == DW_DLV_OK);
+                        auto res2 = wrap(dwarf_linesrc, found_line, &filename);
+                        if(!res2) {
+                            res2.drop_error();
+                            return;
+                        } else if(res2.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         auto wrapper = raii_wrap(
                             filename,
                             [this] (char* str) { if(str) dwarf_dealloc(dbg, str, DW_DLA_STRING); }
@@ -814,7 +980,14 @@ namespace libdwarf {
                         frame.filename = filename;
                     } else {
                         Dwarf_Bool is_line_end;
-                        VERIFY(wrap(dwarf_lineendsequence, line, &is_line_end) == DW_DLV_OK);
+                        auto res = wrap(dwarf_lineendsequence, line, &is_line_end);
+                        if(!res) {
+                            res.drop_error();
+                            return;
+                        } else if(res.unwrap_value() != DW_DLV_OK) {
+                            ASSERT(false, "dwarf call not ok");
+                            return;
+                        }
                         if(is_line_end) {
                             last_lineaddr = 0;
                             last_line = nullptr;
@@ -841,17 +1014,40 @@ namespace libdwarf {
             if(aranges) {
                 // Try to find pc in aranges
                 Dwarf_Arange arange;
-                if(wrap(dwarf_get_arange, aranges, arange_count, pc, &arange) == DW_DLV_OK) {
+                auto res = wrap(dwarf_get_arange, aranges, arange_count, pc, &arange);
+                if(!res) {
+                    res.drop_error();
+                    return;
+                }
+                if(res.unwrap_value() == DW_DLV_OK) {
                     // Address in table, load CU die
                     Dwarf_Off cu_die_offset;
-                    VERIFY(wrap(dwarf_get_cu_die_offset, arange, &cu_die_offset) == DW_DLV_OK);
+                    auto res = wrap(dwarf_get_cu_die_offset, arange, &cu_die_offset);
+                    if(!res) {
+                        res.drop_error();
+                        return;
+                    } else if(res.unwrap_value() != DW_DLV_OK) {
+                        ASSERT(false, "dwarf call not ok");
+                        return;
+                    }
                     Dwarf_Die raw_die;
                     // Setting is_info = true for now, assuming in .debug_info rather than .debug_types
-                    VERIFY(wrap(dwarf_offdie_b, dbg, cu_die_offset, true, &raw_die) == DW_DLV_OK);
+                    auto res2 = wrap(dwarf_offdie_b, dbg, cu_die_offset, true, &raw_die);
+                    if(!res2) {
+                        res2.drop_error();
+                        return;
+                    } else if(res2.unwrap_value() != DW_DLV_OK) {
+                        ASSERT(false, "dwarf call not ok");
+                        return;
+                    }
                     die_object cu_die(dbg, raw_die);
                     Dwarf_Half offset_size = 0;
                     Dwarf_Half dwversion = 0;
-                    VERIFY(dwarf_get_version_of_die(cu_die.get(), &dwversion, &offset_size) == DW_DLV_OK);
+                    int res3 = dwarf_get_version_of_die(cu_die.get(), &dwversion, &offset_size);
+                    if(res3 != DW_DLV_OK) {
+                        ASSERT(false, "dwarf call not ok");
+                        return;
+                    }
                     if(trace_dwarf) {
                         std::fprintf(stderr, "Found CU in aranges\n");
                         cu_die.print();
@@ -870,19 +1066,23 @@ namespace libdwarf {
                 walk_compilation_units([this, pc, &frame, &inlines] (const die_object& cu_die) {
                     Dwarf_Half offset_size = 0;
                     Dwarf_Half dwversion = 0;
-                    dwarf_get_version_of_die(cu_die.get(), &dwversion, &offset_size);
+                    auto res = dwarf_get_version_of_die(cu_die.get(), &dwversion, &offset_size);
+                    if(res != DW_DLV_OK) {
+                        ASSERT(false, "dwarf call not ok");
+                        return true;
+                    }
                     //auto p = cu_die.get_pc_range(dwversion);
                     //cu_die.print();
                     //fprintf(stderr, "        %llx, %llx\n", p.first, p.second);
                     if(trace_dwarf) {
-                        std::fprintf(stderr, "CU: %d %s\n", dwversion, cu_die.get_name().c_str());
+                        microfmt::print(std::cerr, "CU: {} {}\n", dwversion, cu_die.get_name().value_or("<error>"));
                     }
                     if(cu_die.pc_in_die(dwversion, pc)) {
                         if(trace_dwarf) {
                             std::fprintf(
                                 stderr,
                                 "pc in die %08llx %s (now searching for %08llx)\n",
-                                to_ull(cu_die.get_global_offset()),
+                                to_ull(cu_die.get_global_offset().value_or(0)),
                                 cu_die.get_tag_name(),
                                 to_ull(pc)
                             );

src/utils/dwarf.hpp

@@ -17,20 +17,57 @@
  #include <dwarf.h>
 #endif
 
+#define CONCAT_IMPL( x, y ) x##y
+#define CONCAT( x, y ) CONCAT_IMPL( x, y )
+
 namespace cpptrace {
 namespace detail {
 namespace libdwarf {
     static_assert(std::is_pointer<Dwarf_Die>::value, "Dwarf_Die not a pointer");
     static_assert(std::is_pointer<Dwarf_Debug>::value, "Dwarf_Debug not a pointer");
 
-    [[noreturn]] void handle_dwarf_error(Dwarf_Debug dbg, Dwarf_Error error) {
+    static NODISCARD ErrorResult<internal_error> handle_dwarf_error(Dwarf_Debug, Dwarf_Error error) {
         Dwarf_Unsigned ev = dwarf_errno(error);
         char* msg = dwarf_errmsg(error);
-        (void)dbg;
-        // dwarf_dealloc_error(dbg, error);
-        throw internal_error("Cpptrace dwarf error {} {}", ev, msg);
+        return {internal_error("Cpptrace dwarf error {} {}", ev, msg)};
     }
 
+    #define CHECK_OK_IMPL(res_var, expr) \
+        Result<int, internal_error> res_var = (expr); \
+        if(!res_var) { \
+            return std::move(res_var).unwrap_error(); \
+        } else if(res_var.unwrap_value() != DW_DLV_OK) { \
+            return Error( \
+                internal_error( \
+                    "dwarf error: {} didn't evaluate to DW_DLV_OK, instead got {}", \
+                    #expr, \
+                    res_var.unwrap_value() \
+                ) \
+            ); \
+        }
+
+    // Check if the expression is an error or not DW_DLV_OK and error if either
+    #define CHECK_OK(expr) CHECK_OK_IMPL(CONCAT(res, __COUNTER__), (expr))
+
+    #define PROP_ASSIGN_IMPL(var, res_var, expr) \
+        auto res_var = (expr); \
+        if(!res_var) { \
+            return std::move(res_var).unwrap_error(); \
+        } \
+        auto var = res_var.unwrap_value();
+
+    // If the expression is an error, return the error. Otherwise assign the value to the variable.
+    #define PROP_ASSIGN(var, expr) PROP_ASSIGN_IMPL(var, CONCAT(res, __COUNTER__), (expr))
+
+    #define PROP_IMPL(res_var, expr) \
+        auto res_var = (expr); \
+        if(!res_var) { \
+            return std::move(res_var).unwrap_error(); \
+        }
+
+    // If the expression is an error, return the error. Otherwise assign the value to the variable.
+    #define PROP(expr) PROP_IMPL(CONCAT(res, __COUNTER__), (expr))
+
     struct die_object {
         Dwarf_Debug dbg = nullptr;
         Dwarf_Die die = nullptr;
@@ -51,19 +88,29 @@ namespace libdwarf {
                 int
             >::type = 0
         >
-        int wrap(int (*f)(Args...), Args2&&... args) const {
+        Result<int, internal_error> wrap(int (*f)(Args...), Args2&&... args) const {
             Dwarf_Error error = nullptr;
             int ret = f(std::forward<Args2>(args)..., &error);
             if(ret == DW_DLV_ERROR) {
-                handle_dwarf_error(dbg, error);
+                return handle_dwarf_error(dbg, error);
             }
-            return ret;
+            return Ok(ret);
         }
 
+    public:
         die_object(Dwarf_Debug dbg, Dwarf_Die die) : dbg(dbg), die(die) {
             ASSERT(dbg != nullptr);
         }
 
+    // public:
+        // Result<die_object, internal_error> create(Dwarf_Debug dbg, Dwarf_Die die) {
+        //     if(die == nullptr) {
+        //         return internal_error("Error creating dwarf die object: Nullptr");
+        //     } else {
+        //         return die_object(dbg, die);
+        //     }
+        // }
+
         ~die_object() {
             if(die) {
                 dwarf_dealloc_die(die);
@@ -87,39 +134,42 @@ namespace libdwarf {
             return *this;
         }
 
-        die_object clone() const {
-            Dwarf_Off global_offset = get_global_offset();
+        Result<die_object, internal_error> clone() const {
+            auto global_offset = get_global_offset();
+            if(!global_offset) {
+                return global_offset.unwrap_error();
+            }
             Dwarf_Bool is_info = dwarf_get_die_infotypes_flag(die);
             Dwarf_Die die_copy = nullptr;
-            VERIFY(wrap(dwarf_offdie_b, dbg, global_offset, is_info, &die_copy) == DW_DLV_OK);
-            return {dbg, die_copy};
+            CHECK_OK(wrap(dwarf_offdie_b, dbg, global_offset.unwrap_value(), is_info, &die_copy));
+            return die_object(dbg, die_copy);
         }
 
-        die_object get_child() const {
+        Result<die_object, internal_error> get_child() const {
             Dwarf_Die child = nullptr;
-            int ret = wrap(dwarf_child, die, &child);
+            PROP_ASSIGN(ret, wrap(dwarf_child, die, &child));
             if(ret == DW_DLV_OK) {
                 return die_object(dbg, child);
             } else if(ret == DW_DLV_NO_ENTRY) {
                 return die_object(dbg, nullptr);
             } else {
-                PANIC();
+                return internal_error("dwarf error: Unexpected return from dwarf_child {}", ret);
             }
         }
 
-        die_object get_sibling() const {
+        Result<die_object, internal_error> get_sibling() const {
             Dwarf_Die sibling = nullptr;
-            int ret = wrap(dwarf_siblingof_b, dbg, die, true, &sibling);
+            PROP_ASSIGN(ret, wrap(dwarf_siblingof_b, dbg, die, true, &sibling));
             if(ret == DW_DLV_OK) {
                 return die_object(dbg, sibling);
             } else if(ret == DW_DLV_NO_ENTRY) {
                 return die_object(dbg, nullptr);
             } else {
-                PANIC();
+                return internal_error("dwarf error: Unexpected return from dwarf_siblingof_b {}", ret);
             }
         }
 
-        operator bool() const {
+        explicit operator bool() const {
             return die != nullptr;
         }
 
@@ -127,79 +177,83 @@ namespace libdwarf {
             return die;
         }
 
-        std::string get_name() const {
+        Result<std::string, internal_error> get_name() const {
             char empty[] = "";
             char* name = empty;
-            int ret = wrap(dwarf_diename, die, &name);
+            PROP_ASSIGN(ret, wrap(dwarf_diename, die, &name));
             auto wrapper = raii_wrap(name, [this] (char* str) { dwarf_dealloc(dbg, str, DW_DLA_STRING); });
             std::string str;
             if(ret != DW_DLV_NO_ENTRY) {
                 str = name;
             }
-            return name;
+            return std::string(name);
         }
 
-        optional<std::string> get_string_attribute(Dwarf_Half attr_num) const {
+        Result<optional<std::string>, internal_error> get_string_attribute(Dwarf_Half attr_num) const {
             Dwarf_Attribute attr;
-            if(wrap(dwarf_attr, die, attr_num, &attr) == DW_DLV_OK) {
+            auto ret = wrap(dwarf_attr, die, attr_num, &attr);
+            if(ret.is_error()) {
+                ret.drop_error();
+            } else if(ret.unwrap_value() == DW_DLV_OK) {
                 auto attwrapper = raii_wrap(attr, [] (Dwarf_Attribute attr) { dwarf_dealloc_attribute(attr); });
                 char* raw_str;
-                VERIFY(wrap(dwarf_formstring, attr, &raw_str) == DW_DLV_OK);
+                CHECK_OK(wrap(dwarf_formstring, attr, &raw_str));
                 auto strwrapper = raii_wrap(raw_str, [this] (char* str) { dwarf_dealloc(dbg, str, DW_DLA_STRING); });
                 std::string str = raw_str;
-                return str;
-            } else {
-                return nullopt;
+                return Ok(str);
             }
+            return Ok(nullopt);
         }
 
-        optional<Dwarf_Unsigned> get_unsigned_attribute(Dwarf_Half attr_num) const {
+        Result<optional<Dwarf_Unsigned>, internal_error> get_unsigned_attribute(Dwarf_Half attr_num) const {
             Dwarf_Attribute attr;
-            if(wrap(dwarf_attr, die, attr_num, &attr) == DW_DLV_OK) {
+            auto ret = wrap(dwarf_attr, die, attr_num, &attr);
+            if (ret.is_error()) {
+                ret.drop_error();
+            } else if(ret.unwrap_value() == DW_DLV_OK) {
                 auto attwrapper = raii_wrap(attr, [] (Dwarf_Attribute attr) { dwarf_dealloc_attribute(attr); });
-                // Dwarf_Half form = 0;
-                // VERIFY(wrap(dwarf_whatform, attr, &form) == DW_DLV_OK);
                 Dwarf_Unsigned val;
-                VERIFY(wrap(dwarf_formudata, attr, &val) == DW_DLV_OK);
-                return val;
-            } else {
-                return nullopt;
+                CHECK_OK(wrap(dwarf_formudata, attr, &val));
+                return Ok(val);
             }
+            return Ok(nullopt);
         }
 
-        bool has_attr(Dwarf_Half attr_num) const {
+        Result<bool, internal_error> has_attr(Dwarf_Half attr_num) const {
             Dwarf_Bool present = false;
-            VERIFY(wrap(dwarf_hasattr, die, attr_num, &present) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_hasattr, die, attr_num, &present));
             return present;
         }
 
-        Dwarf_Half get_tag() const {
+        Result<Dwarf_Half, internal_error> get_tag() const {
             Dwarf_Half tag = 0;
-            VERIFY(wrap(dwarf_tag, die, &tag) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_tag, die, &tag));
             return tag;
         }
 
         const char* get_tag_name() const {
             const char* tag_name;
-            if(dwarf_get_TAG_name(get_tag(), &tag_name) == DW_DLV_OK) {
+            auto tag = get_tag();
+            if(!tag) {
+                tag.drop_error();
+            } else if(dwarf_get_TAG_name(tag.unwrap_value(), &tag_name) == DW_DLV_OK) {
                 return tag_name;
-            } else {
-                return "<unknown tag name>";
             }
+            return "<unknown tag name>";
         }
 
-        Dwarf_Off get_global_offset() const {
+        Result<Dwarf_Off, internal_error> get_global_offset() const {
             Dwarf_Off off;
-            VERIFY(wrap(dwarf_dieoffset, die, &off) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_dieoffset, die, &off));
             return off;
         }
 
-        die_object resolve_reference_attribute(Dwarf_Half attr_num) const {
+        Result<die_object, internal_error> resolve_reference_attribute(Dwarf_Half attr_num) const {
             Dwarf_Attribute attr;
-            VERIFY(dwarf_attr(die, attr_num, &attr, nullptr) == DW_DLV_OK);
+            CHECK_OK(dwarf_attr(die, attr_num, &attr, nullptr));
             auto wrapper = raii_wrap(attr, [] (Dwarf_Attribute attr) { dwarf_dealloc_attribute(attr); });
             Dwarf_Half form = 0;
-            VERIFY(wrap(dwarf_whatform, attr, &form) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_whatform, attr, &form));
             switch(form) {
                 case DW_FORM_ref1:
                 case DW_FORM_ref2:
@@ -209,77 +263,86 @@ namespace libdwarf {
                     {
                         Dwarf_Off off = 0;
                         Dwarf_Bool is_info = dwarf_get_die_infotypes_flag(die);
-                        VERIFY(wrap(dwarf_formref, attr, &off, &is_info) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_formref, attr, &off, &is_info));
                         Dwarf_Off global_offset = 0;
-                        VERIFY(wrap(dwarf_convert_to_global_offset, attr, off, &global_offset) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_convert_to_global_offset, attr, off, &global_offset));
                         Dwarf_Die target = nullptr;
-                        VERIFY(wrap(dwarf_offdie_b, dbg, global_offset, is_info, &target) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_offdie_b, dbg, global_offset, is_info, &target));
                         return die_object(dbg, target);
                     }
                 case DW_FORM_ref_addr:
                     {
                         Dwarf_Off off;
-                        VERIFY(wrap(dwarf_global_formref, attr, &off) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_global_formref, attr, &off));
                         int is_info = dwarf_get_die_infotypes_flag(die);
                         Dwarf_Die target = nullptr;
-                        VERIFY(wrap(dwarf_offdie_b, dbg, off, is_info, &target) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_offdie_b, dbg, off, is_info, &target));
                         return die_object(dbg, target);
                     }
                 case DW_FORM_ref_sig8:
                     {
                         Dwarf_Sig8 signature;
-                        VERIFY(wrap(dwarf_formsig8, attr, &signature) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_formsig8, attr, &signature));
                         Dwarf_Die target = nullptr;
                         Dwarf_Bool targ_is_info = false;
-                        VERIFY(wrap(dwarf_find_die_given_sig8, dbg, &signature, &target, &targ_is_info) == DW_DLV_OK);
+                        CHECK_OK(wrap(dwarf_find_die_given_sig8, dbg, &signature, &target, &targ_is_info));
                         return die_object(dbg, target);
                     }
                 default:
-                    PANIC(microfmt::format("unknown form for attribute {} {}\n", attr_num, form));
+                    return internal_error(microfmt::format("unknown form for attribute {} {}", attr_num, form));
             }
         }
 
-        Dwarf_Unsigned get_ranges_offset(Dwarf_Attribute attr) const {
+        Result<Dwarf_Unsigned, internal_error> get_ranges_offset(Dwarf_Attribute attr) const {
             Dwarf_Unsigned off = 0;
             Dwarf_Half form = 0;
-            VERIFY(wrap(dwarf_whatform, attr, &form) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_whatform, attr, &form));
             if (form == DW_FORM_rnglistx) {
-                VERIFY(wrap(dwarf_formudata, attr, &off) == DW_DLV_OK);
+                CHECK_OK(wrap(dwarf_formudata, attr, &off));
             } else {
-                VERIFY(wrap(dwarf_global_formref, attr, &off) == DW_DLV_OK);
+                CHECK_OK(wrap(dwarf_global_formref, attr, &off));
             }
             return off;
         }
 
         template<typename F>
         // callback should return true to keep going
-        void dwarf5_ranges(F callback) const {
+        NODISCARD
+        Result<monostate, internal_error> dwarf5_ranges(F callback) const {
             Dwarf_Attribute attr = nullptr;
-            if(wrap(dwarf_attr, die, DW_AT_ranges, &attr) != DW_DLV_OK) {
-                return;
+            auto ranges_res = wrap(dwarf_attr, die, DW_AT_ranges, &attr);
+            if(ranges_res.is_error()) {
+                return ranges_res.unwrap_error();
+            } else if(ranges_res.unwrap_value() != DW_DLV_OK) {
+                return monostate{}; // normal
             }
             auto attrwrapper = raii_wrap(attr, [] (Dwarf_Attribute attr) { dwarf_dealloc_attribute(attr); });
-            Dwarf_Unsigned offset = get_ranges_offset(attr);
+            PROP_ASSIGN(offset, get_ranges_offset(attr));
             Dwarf_Half form = 0;
-            VERIFY(wrap(dwarf_whatform, attr, &form) == DW_DLV_OK);
+            CHECK_OK(wrap(dwarf_whatform, attr, &form));
             // get .debug_rnglists info
             Dwarf_Rnglists_Head head = nullptr;
             Dwarf_Unsigned rnglists_entries = 0;
             Dwarf_Unsigned dw_global_offset_of_rle_set = 0;
-            int res = wrap(
-                dwarf_rnglists_get_rle_head,
-                attr,
-                form,
-                offset,
-                &head,
-                &rnglists_entries,
-                &dw_global_offset_of_rle_set
+            PROP_ASSIGN(
+                res,
+                wrap(
+                    dwarf_rnglists_get_rle_head,
+                    attr,
+                    form,
+                    offset,
+                    &head,
+                    &rnglists_entries,
+                    &dw_global_offset_of_rle_set
+                )
             );
             auto headwrapper = raii_wrap(head, [] (Dwarf_Rnglists_Head head) { dwarf_dealloc_rnglists_head(head); });
             if(res == DW_DLV_NO_ENTRY) {
-                return;
+                return monostate{}; // I guess normal
+            }
+            if(res != DW_DLV_OK) {
+                return internal_error("dwarf_rnglists_get_rle_head not ok");
             }
-            VERIFY(res == DW_DLV_OK);
             for(std::size_t i = 0 ; i < rnglists_entries; i++) {
                 unsigned entrylen = 0;
                 unsigned rle_value_out = 0;
@@ -288,22 +351,27 @@ namespace libdwarf {
                 Dwarf_Bool unavailable = 0;
                 Dwarf_Unsigned cooked1 = 0;
                 Dwarf_Unsigned cooked2 = 0;
-                res = wrap(
-                    dwarf_get_rnglists_entry_fields_a,
-                    head,
-                    i,
-                    &entrylen,
-                    &rle_value_out,
-                    &raw1,
-                    &raw2,
-                    &unavailable,
-                    &cooked1,
-                    &cooked2
+                PROP_ASSIGN(
+                    res2,
+                    wrap(
+                        dwarf_get_rnglists_entry_fields_a,
+                        head,
+                        i,
+                        &entrylen,
+                        &rle_value_out,
+                        &raw1,
+                        &raw2,
+                        &unavailable,
+                        &cooked1,
+                        &cooked2
+                    )
                 );
-                if(res == DW_DLV_NO_ENTRY) {
+                if(res2 == DW_DLV_NO_ENTRY) {
                     continue;
                 }
-                VERIFY(res == DW_DLV_OK);
+                if(res2 != DW_DLV_OK) {
+                    return internal_error("dwarf_get_rnglists_entry_fields_a not ok");
+                }
                 if(unavailable) {
                     continue;
                 }
@@ -320,27 +388,31 @@ namespace libdwarf {
                     case DW_RLE_startx_length:
                     case DW_RLE_start_length:
                         if(!callback(cooked1, cooked2)) {
-                            return;
+                            return monostate{};
                         }
                         break;
                     default:
-                        PANIC("Something is wrong");
+                        return internal_error("rle_value_out: something is wrong");
                         break;
                 }
             }
+            return monostate{};
         }
 
         template<typename F>
         // callback should return true to keep going
-        void dwarf4_ranges(Dwarf_Addr lowpc, F callback) const {
+        NODISCARD
+        Result<monostate, internal_error> dwarf4_ranges(Dwarf_Addr lowpc, F callback) const {
             Dwarf_Attribute attr = nullptr;
-            if(wrap(dwarf_attr, die, DW_AT_ranges, &attr) != DW_DLV_OK) {
-                return;
+            PROP_ASSIGN(res, wrap(dwarf_attr, die, DW_AT_ranges, &attr));
+            if(res != DW_DLV_OK) {
+                return monostate{}; // normal
             }
             auto attrwrapper = raii_wrap(attr, [] (Dwarf_Attribute attr) { dwarf_dealloc_attribute(attr); });
             Dwarf_Unsigned offset;
-            if(wrap(dwarf_global_formref, attr, &offset) != DW_DLV_OK) {
-                return;
+            PROP_ASSIGN(res2, wrap(dwarf_global_formref, attr, &offset));
+            if(res2 != DW_DLV_OK) {
+                return monostate{}; // normal
             }
             Dwarf_Addr baseaddr = 0;
             if(lowpc != (std::numeric_limits<Dwarf_Addr>::max)()) {
@@ -348,7 +420,7 @@ namespace libdwarf {
             }
             Dwarf_Ranges* ranges = nullptr;
             Dwarf_Signed count = 0;
-            VERIFY(
+            CHECK_OK(
                 wrap(
                     dwarf_get_ranges_b,
                     dbg,
@@ -358,7 +430,7 @@ namespace libdwarf {
                     &ranges,
                     &count,
                     nullptr
-                ) == DW_DLV_OK
+                )
             );
             auto rangeswrapper = raii_wrap(
                 ranges,
@@ -367,7 +439,7 @@ namespace libdwarf {
             for(int i = 0; i < count; i++) {
                 if(ranges[i].dwr_type == DW_RANGES_ENTRY) {
                     if(!callback(baseaddr + ranges[i].dwr_addr1, baseaddr + ranges[i].dwr_addr2)) {
-                        return;
+                        return monostate{};
                     }
                 } else if(ranges[i].dwr_type == DW_RANGES_ADDRESS_SELECTION) {
                     baseaddr = ranges[i].dwr_addr2;
@@ -376,63 +448,76 @@ namespace libdwarf {
                     baseaddr = lowpc;
                 }
             }
+            return monostate{};
         }
 
         template<typename F>
         // callback should return true to keep going
-        void dwarf_ranges(int version, optional<Dwarf_Addr> pc, F callback) const {
+        NODISCARD
+        Result<monostate, internal_error> dwarf_ranges(int version, optional<Dwarf_Addr> pc, F callback) const {
             Dwarf_Addr lowpc = (std::numeric_limits<Dwarf_Addr>::max)();
-            if(wrap(dwarf_lowpc, die, &lowpc) == DW_DLV_OK) {
+            PROP_ASSIGN(res, wrap(dwarf_lowpc, die, &lowpc));
+            if(res == DW_DLV_OK) {
                 if(pc.has_value() && pc.unwrap() == lowpc) {
                     callback(lowpc, lowpc + 1);
-                    return;
+                    return monostate{};
                 }
                 Dwarf_Addr highpc = 0;
                 enum Dwarf_Form_Class return_class;
-                if(wrap(dwarf_highpc_b, die, &highpc, nullptr, &return_class) == DW_DLV_OK) {
+                PROP_ASSIGN(res2, wrap(dwarf_highpc_b, die, &highpc, nullptr, &return_class));
+                if(res2 == DW_DLV_OK) {
                     if(return_class == DW_FORM_CLASS_CONSTANT) {
                         highpc += lowpc;
                     }
                     if(!callback(lowpc, highpc)) {
-                        return;
+                        return monostate{};
                     }
                 }
             }
             if(version >= 5) {
-                dwarf5_ranges(callback);
+                return dwarf5_ranges(callback);
             } else {
-                dwarf4_ranges(lowpc, callback);
+                return dwarf4_ranges(lowpc, callback);
             }
         }
 
-        std::vector<std::pair<Dwarf_Addr, Dwarf_Addr>> get_rangelist_entries(int version) const {
-            std::vector<std::pair<Dwarf_Addr, Dwarf_Addr>> vec;
-            dwarf_ranges(version, nullopt, [&vec] (Dwarf_Addr low, Dwarf_Addr high) {
-                // Simple coalescing optimization:
-                // Sometimes the range list entries are really continuous: [100, 200), [200, 300)
-                // Other times there's just one byte of separation [300, 399), [400, 500)
-                // Those are the main two cases I've observed.
-                // This will not catch all cases, presumably, as the range lists aren't sorted. But compilers/linkers
-                // seem to like to emit the ranges in sorted order.
-                if(!vec.empty() && low - vec.back().second <= 1) {
-                    vec.back().second = high;
-                } else {
-                    vec.push_back({low, high});
-                }
-                return true;
-            });
+        struct address_range {
+            Dwarf_Addr low;
+            Dwarf_Addr high;
+        };
+
+        Result<std::vector<address_range>, internal_error> get_rangelist_entries(int version) const {
+            std::vector<address_range> vec;
+            PROP(
+                dwarf_ranges(version, nullopt, [&vec] (Dwarf_Addr low, Dwarf_Addr high) {
+                    // Simple coalescing optimization:
+                    // Sometimes the range list entries are really continuous: [100, 200), [200, 300)
+                    // Other times there's just one byte of separation [300, 399), [400, 500)
+                    // Those are the main two cases I've observed.
+                    // This will not catch all cases, presumably, as the range lists aren't sorted.
+                    //  But compilers/linkers seem to like to emit the ranges in sorted order.
+                    if(!vec.empty() && low - vec.back().high <= 1) {
+                        vec.back().high = high;
+                    } else {
+                        vec.push_back({low, high});
+                    }
+                    return true;
+                })
+            );
             return vec;
         }
 
-        Dwarf_Bool pc_in_die(int version, Dwarf_Addr pc) const {
+        Result<Dwarf_Bool, internal_error> pc_in_die(int version, Dwarf_Addr pc) const {
             bool found = false;
-            dwarf_ranges(version, pc, [&found, pc] (Dwarf_Addr low, Dwarf_Addr high) {
-                if(pc >= low && pc < high) {
-                    found = true;
-                    return false;
-                }
-                return true;
-            });
+            PROP(
+                dwarf_ranges(version, pc, [&found, pc] (Dwarf_Addr low, Dwarf_Addr high) {
+                    if(pc >= low && pc < high) {
+                        found = true;
+                        return false;
+                    }
+                    return true;
+                })
+            );
             return found;
         }
 
@@ -440,9 +525,9 @@ namespace libdwarf {
             std::fprintf(
                 stderr,
                 "%08llx %s %s\n",
-                to_ull(get_global_offset()),
+                to_ull(get_global_offset().value_or(0)),
                 get_tag_name(),
-                get_name().c_str()
+                get_name().drop_error().value_or("<name error>").c_str()
             );
         }
     };
@@ -457,13 +542,22 @@ namespace libdwarf {
         // TODO: Refactor so there is only one fn call
         bool continue_traversal = true;
         if(fn(die)) {
-            die_object current = die.get_sibling();
-            while(current) {
-                if(fn(current)) {
-                    current = current.get_sibling();
-                } else {
-                    continue_traversal = false;
-                    break;
+            auto sibling = die.get_sibling();
+            if(!sibling) {
+                sibling.drop_error();
+            } else {
+                die_object current = std::move(sibling).unwrap_value();
+                while(current) {
+                    if(fn(current)) {
+                        auto sibling = current.get_sibling();
+                        if(!sibling) {
+                            sibling.drop_error();
+                        }
+                        current = std::move(sibling).unwrap_value();
+                    } else {
+                        continue_traversal = false;
+                        break;
+                    }
                 }
             }
         }
@@ -481,8 +575,10 @@ namespace libdwarf {
             die,
             [&fn](const die_object& die) {
                 auto child = die.get_child();
-                if(child) {
-                    if(!walk_die_list_recursive(child, fn)) {
+                if(child.is_error()) {
+                    child.drop_error();
+                } else if(child.unwrap_value()) {
+                    if(!walk_die_list_recursive(child.unwrap_value(), fn)) {
                         return false;
                     }
                 }

src/utils/error.hpp

@@ -20,9 +20,10 @@ namespace detail {
     class internal_error : public std::exception {
         std::string msg;
     public:
-        internal_error(std::string message) : msg(std::move(message)) {}
+        internal_error(std::string message) : msg("Cpptrace internal error: " + std::move(message)) {}
         template<typename... Args>
-        internal_error(const char* format, Args&&... args) : msg(microfmt::format(format, args...)) {}
+        internal_error(const char* format, Args&&... args)
+            : msg("Cpptrace internal error: " + microfmt::format(format, args...)) {}
         const char* what() const noexcept override {
             return msg.c_str();
         }
@@ -75,23 +76,27 @@ namespace detail {
         }
     }
 
-    [[noreturn]] inline void panic(
-        const char* signature,
-        source_location location,
-        const std::string& message = ""
-    ) {
-        if(message == "") {
-            throw internal_error(
-                "Cpptrace panic {}:{}: {}\n",
-                location.file, location.line, signature
-            );
-        } else {
-            throw internal_error(
-                "Cpptrace panic {}:{}: {}: {}\n",
-                location.file, location.line, signature, message.c_str()
-            );
-        }
-    }
+    // [[noreturn]] inline void panic(
+    //     const char* signature,
+    //     source_location location,
+    //     const std::string& message = ""
+    // ) {
+    //     if(message == "") {
+    //         throw internal_error(
+    //             stringf(
+    //                 "Cpptrace panic %s:%d: %s\n",
+    //                 location.file, location.line, signature
+    //             )
+    //         );
+    //     } else {
+    //         throw internal_error(
+    //             stringf(
+    //                 "Cpptrace panic %s:%d: %s: %s\n",
+    //                 location.file, location.line, signature, message.c_str()
+    //             )
+    //         );
+    //     }
+    // }
 
     template<typename T>
     void nullfn() {
@@ -107,7 +112,7 @@ namespace detail {
     }
 
     // Check condition in both debug and release. std::runtime_error on failure.
-    #define VERIFY(c, ...) ( \
+    /*#define VERIFY(c, ...) ( \
             (::cpptrace::detail::as_bool(c)) \
                 ? static_cast<void>(0) \
                 : (::cpptrace::detail::assert_fail)( \
@@ -116,7 +121,7 @@ namespace detail {
                     CPPTRACE_PFUNC, \
                     {}, \
                     ##__VA_ARGS__) \
-    )
+    )*/
 
     // Workaround a compiler warning
     template<typename T>
@@ -128,8 +133,8 @@ namespace detail {
         return "";
     }
 
-    // Check condition in both debug and release. std::runtime_error on failure.
-    #define PANIC(...) ((::cpptrace::detail::panic)(CPPTRACE_PFUNC, {}, ::cpptrace::detail::as_string(__VA_ARGS__)))
+    // // Check condition in both debug and release. std::runtime_error on failure.
+    // #define PANIC(...) ((::cpptrace::detail::panic)(CPPTRACE_PFUNC, {}, ::cpptrace::detail::as_string(__VA_ARGS__)))
 
     #ifndef NDEBUG
      // Check condition in both debug. std::runtime_error on failure.

src/utils/utils.hpp

@@ -325,6 +325,26 @@ namespace detail {
         }
     };
 
+    template<typename T>
+    struct OkResult {
+        T value;
+    };
+
+    template<typename T>
+    struct ErrorResult {
+        T value;
+    };
+
+    template<typename T>
+    OkResult<T> Ok(T value) {
+        return {value};
+    }
+
+    template<typename T>
+    ErrorResult<T> Error(T value) {
+        return {value};
+    }
+
     // TODO: Better dump error
     // TODO: Explicit constructors for value, then add Ok()/Error() helpers
     template<typename T, typename E, typename std::enable_if<!std::is_same<T, E>::value, int>::type = 0>
@@ -339,6 +359,10 @@ namespace detail {
     public:
         Result(T value) : value_(std::move(value)), active(member::value) {}
         Result(E error) : error_(std::move(error)), active(member::error) {}
+        template<typename U>
+        Result(OkResult<U>&& value) : value_(std::move(value.value)), active(member::value) {}
+        template<typename U>
+        Result(ErrorResult<U>&& error) : error_(std::move(error.value)), active(member::error) {}
         Result(Result&& other) : active(other.active) {
             if(other.active == member::value) {
                 new (&value_) T(std::move(other.value_));
@@ -422,10 +446,11 @@ namespace detail {
             return has_value() ? std::move(value_) : static_cast<T>(std::forward<U>(default_value));
         }
 
-        void drop_error() const {
+        const Result& drop_error() const {
             if(is_error()) {
                 std::fprintf(stderr, "%s\n", unwrap_error().what());
             }
+            return *this;
         }
     };