Error handling improvements (#46)

README.md

@@ -218,9 +218,11 @@ namespace cpptrace {
 ### Utilities
 
 `cpptrace::demangle` provides a helper function for name demangling, since it has to implement that helper internally
-anyways. It also provides a function to control whether any exceptions that are throw internally are caught and ignored
-before returning to user code. The library makes an attempt to fail silently during trace generation if any errors are
-encountered.
+anyways.
+
+The library makes an attempt to fail silently and continue during trace generation if any errors are encountered.
+`cpptrace::absorb_trace_exceptions` can be used to configure whether these exceptions are absorbed silently internally
+or wether they're rethrown to the caller.
 
 ```cpp
 namespace cpptrace {

src/cpptrace.cpp

@@ -42,16 +42,30 @@ namespace cpptrace {
 
     CPPTRACE_API
     object_trace raw_trace::resolve_object_trace() const {
-        return object_trace(detail::get_frames_object_info(frames));
+        try {
+            return object_trace(detail::get_frames_object_info(frames));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return object_trace({});
+        }
     }
 
     CPPTRACE_API
     stacktrace raw_trace::resolve() const {
-        std::vector<stacktrace_frame> trace = detail::resolve_frames(frames);
-        for(auto& frame : trace) {
-            frame.symbol = detail::demangle(frame.symbol);
+        try {
+            std::vector<stacktrace_frame> trace = detail::resolve_frames(frames);
+            for(auto& frame : trace) {
+                frame.symbol = detail::demangle(frame.symbol);
+            }
+            return stacktrace(std::move(trace));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return stacktrace();
         }
-        return stacktrace(std::move(trace));
     }
 
     CPPTRACE_API
@@ -76,7 +90,14 @@ namespace cpptrace {
 
     CPPTRACE_API
     stacktrace object_trace::resolve() const {
-        return stacktrace(detail::resolve_frames(frames));
+        try {
+            return stacktrace(detail::resolve_frames(frames));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return stacktrace();
+        }
     }
 
     CPPTRACE_API
@@ -222,22 +243,50 @@ namespace cpptrace {
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     raw_trace generate_raw_trace(std::uint_least32_t skip) {
-        return raw_trace(detail::capture_frames(skip + 1, UINT_LEAST32_MAX));
+        try {
+            return raw_trace(detail::capture_frames(skip + 1, UINT_LEAST32_MAX));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return raw_trace({});
+        }
     }
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     raw_trace generate_raw_trace(std::uint_least32_t skip, std::uint_least32_t max_depth) {
-        return raw_trace(detail::capture_frames(skip + 1, max_depth));
+        try {
+            return raw_trace(detail::capture_frames(skip + 1, max_depth));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return raw_trace({});
+        }
     }
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     object_trace generate_object_trace(std::uint_least32_t skip) {
-        return object_trace(detail::get_frames_object_info(detail::capture_frames(skip + 1, UINT_LEAST32_MAX)));
+        try {
+            return object_trace(detail::get_frames_object_info(detail::capture_frames(skip + 1, UINT_LEAST32_MAX)));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return object_trace({});
+        }
     }
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     object_trace generate_object_trace(std::uint_least32_t skip, std::uint_least32_t max_depth) {
-        return object_trace(detail::get_frames_object_info(detail::capture_frames(skip + 1, max_depth)));
+        try {
+            return object_trace(detail::get_frames_object_info(detail::capture_frames(skip + 1, max_depth)));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return object_trace({});
+        }
     }
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
@@ -247,12 +296,19 @@ namespace cpptrace {
 
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     stacktrace generate_trace(std::uint32_t skip, std::uint_least32_t max_depth) {
-        std::vector<uintptr_t> frames = detail::capture_frames(skip + 1, max_depth);
-        std::vector<stacktrace_frame> trace = detail::resolve_frames(frames);
-        for(auto& frame : trace) {
-            frame.symbol = detail::demangle(frame.symbol);
+        try {
+            std::vector<uintptr_t> frames = detail::capture_frames(skip + 1, max_depth);
+            std::vector<stacktrace_frame> trace = detail::resolve_frames(frames);
+            for(auto& frame : trace) {
+                frame.symbol = detail::demangle(frame.symbol);
+            }
+            return stacktrace(std::move(trace));
+        } catch(...) {
+            if(!detail::should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return stacktrace();
         }
-        return stacktrace(std::move(trace));
     }
 
     CPPTRACE_API

src/platform/common.hpp

@@ -60,6 +60,8 @@ namespace detail {
         snprintf(&str[0], length + 1, args...);
         return str;
     }
+
+    static const stacktrace_frame null_frame {0, 0, UINT_LEAST32_MAX, "", ""};
 }
 }
 

src/platform/utils.hpp

@@ -126,7 +126,7 @@ namespace detail {
         return byte_swapper<T, sizeof(T)>{}(value);
     }
 
-    inline void enable_virtual_terminal_processing_if_needed() {
+    inline void enable_virtual_terminal_processing_if_needed() noexcept {
         // enable colors / ansi processing if necessary
         #if IS_WINDOWS
          // https://docs.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences#example-of-enabling-virtual-terminal-processing
@@ -142,7 +142,7 @@ namespace detail {
         #endif
     }
 
-    inline constexpr unsigned n_digits(unsigned value) {
+    inline constexpr unsigned n_digits(unsigned value) noexcept {
         return value < 10 ? 1 : 1 + n_digits(value / 10);
     }
     static_assert(n_digits(1) == 1, "n_digits utility producing the wrong result");

src/symbols/symbols_with_addr2line.cpp

@@ -267,7 +267,7 @@ namespace addr2line {
 
     std::vector<stacktrace_frame> resolve_frames(const std::vector<object_frame>& frames) {
         // TODO: Refactor better
-        std::vector<stacktrace_frame> trace(frames.size(), stacktrace_frame { 0, 0, UINT_LEAST32_MAX, "", "" });
+        std::vector<stacktrace_frame> trace(frames.size(), null_frame);
         for(size_t i = 0; i < frames.size(); i++) {
             trace[i].address = frames[i].raw_address;
             // Set what is known for now, and resolutions from addr2line should overwrite
@@ -277,28 +277,34 @@ namespace addr2line {
         if(has_addr2line()) {
             const auto entries = collate_frames(frames, trace);
             for(const auto& entry : entries) {
-                const auto& object_name = entry.first;
-                const auto& entries_vec = entry.second;
-                // You may ask why it'd ever happen that there could be an empty entries_vec array, if there're
-                // no addresses why would get_addr2line_targets do anything? The reason is because if things in
-                // get_addr2line_targets fail it will silently skip. This is partly an optimization but also an
-                // assertion below will fail if addr2line is given an empty input.
-                if(entries_vec.empty()) {
-                    continue;
-                }
-                std::string address_input;
-                for(const auto& pair : entries_vec) {
-                    address_input += to_hex(pair.first.get().obj_address);
-                    #if !IS_WINDOWS
-                        address_input += '\n';
-                    #else
-                        address_input += ' ';
-                    #endif
-                }
-                auto output = split(trim(resolve_addresses(address_input, object_name)), "\n");
-                VERIFY(output.size() == entries_vec.size());
-                for(size_t i = 0; i < output.size(); i++) {
-                    update_trace(output[i], i, entries_vec);
+                try {
+                    const auto& object_name = entry.first;
+                    const auto& entries_vec = entry.second;
+                    // You may ask why it'd ever happen that there could be an empty entries_vec array, if there're
+                    // no addresses why would get_addr2line_targets do anything? The reason is because if things in
+                    // get_addr2line_targets fail it will silently skip. This is partly an optimization but also an
+                    // assertion below will fail if addr2line is given an empty input.
+                    if(entries_vec.empty()) {
+                        continue;
+                    }
+                    std::string address_input;
+                    for(const auto& pair : entries_vec) {
+                        address_input += to_hex(pair.first.get().obj_address);
+                        #if !IS_WINDOWS
+                            address_input += '\n';
+                        #else
+                            address_input += ' ';
+                        #endif
+                    }
+                    auto output = split(trim(resolve_addresses(address_input, object_name)), "\n");
+                    VERIFY(output.size() == entries_vec.size());
+                    for(size_t i = 0; i < output.size(); i++) {
+                        update_trace(output[i], i, entries_vec);
+                    }
+                } catch(...) {
+                    if(!should_absorb_trace_exceptions()) {
+                        throw;
+                    }
                 }
             }
         }

src/symbols/symbols_with_dbghelp.cpp

@@ -382,22 +382,10 @@ namespace dbghelp {
                     signature
                 };
             } else {
-                return {
-                    addr,
-                    0,
-                    UINT_LEAST32_MAX,
-                    "",
-                    symbol->Name
-                };
+                return { addr, 0, UINT_LEAST32_MAX, "", symbol->Name };
             }
         } else {
-            return {
-                addr,
-                0,
-                UINT_LEAST32_MAX,
-                "",
-                ""
-            };
+            return { addr, 0, UINT_LEAST32_MAX, "", "" };
         }
     }
 
@@ -414,7 +402,14 @@ namespace dbghelp {
             throw std::logic_error("SymInitialize failed");
         }
         for(const auto frame : frames) {
-            trace.push_back(resolve_frame(proc, frame));
+            try {
+                trace.push_back(resolve_frame(proc, frame));
+            } catch(...) {
+                if(!detail::should_absorb_trace_exceptions()) {
+                    throw;
+                }
+                trace.push_back(null_frame);
+            }
         }
         if(!SymCleanup(proc)) {
             //throw std::logic_error("SymCleanup failed");

src/symbols/symbols_with_libbacktrace.cpp

@@ -8,6 +8,7 @@
 #include <cstdio>
 #include <memory>
 #include <mutex>
+#include <stdexcept>
 #include <vector>
 
 #ifdef CPPTRACE_BACKTRACE_PATH
@@ -21,9 +22,6 @@ namespace detail {
 namespace libbacktrace {
     int full_callback(void* data, uintptr_t address, const char* file, int line, const char* symbol) {
         stacktrace_frame& frame = *static_cast<stacktrace_frame*>(data);
-        if(line == 0) {
-            ///fprintf(stderr, "Getting bad data for some reason\n"); // TODO: Eliminate
-        }
         frame.address = address;
         frame.line = line;
         frame.filename = file ? file : "";
@@ -40,7 +38,7 @@ namespace libbacktrace {
     }
 
     void error_callback(void*, const char* msg, int errnum) {
-        fprintf(stderr, "Libbacktrace error: %s, code %d\n", msg, errnum);
+        throw std::runtime_error(stringf("Libbacktrace error: %s, code %d\n", msg, errnum));
     }
 
     backtrace_state* get_backtrace_state() {
@@ -58,26 +56,33 @@ namespace libbacktrace {
 
     // TODO: Handle backtrace_pcinfo calling the callback multiple times on inlined functions
     stacktrace_frame resolve_frame(const uintptr_t addr) {
-        stacktrace_frame frame;
-        frame.column = UINT_LEAST32_MAX;
-        backtrace_pcinfo(
-            get_backtrace_state(),
-            addr,
-            full_callback,
-            error_callback,
-            &frame
-        );
-        if(frame.symbol.empty()) {
-            // fallback, try to at least recover the symbol name with backtrace_syminfo
-            backtrace_syminfo(
+        try {
+            stacktrace_frame frame;
+            frame.column = UINT_LEAST32_MAX;
+            backtrace_pcinfo(
                 get_backtrace_state(),
                 addr,
-                syminfo_callback,
+                full_callback,
                 error_callback,
                 &frame
             );
+            if(frame.symbol.empty()) {
+                // fallback, try to at least recover the symbol name with backtrace_syminfo
+                backtrace_syminfo(
+                    get_backtrace_state(),
+                    addr,
+                    syminfo_callback,
+                    error_callback,
+                    &frame
+                );
+            }
+            return frame;
+        } catch(...) {
+            if(!should_absorb_trace_exceptions()) {
+                throw;
+            }
+            return null_frame;
         }
-        return frame;
     }
 
     std::vector<stacktrace_frame> resolve_frames(const std::vector<uintptr_t>& frames) {

src/symbols/symbols_with_libdwarf.cpp

@@ -1089,7 +1089,7 @@ namespace libdwarf {
 
         CPPTRACE_FORCE_NO_INLINE_FOR_PROFILING
         stacktrace_frame resolve_frame(const object_frame& frame_info) {
-            stacktrace_frame frame { 0, 0, UINT_LEAST32_MAX, "", "" };
+            stacktrace_frame frame = null_frame;
             frame.filename = frame_info.obj_path;
             frame.symbol = frame_info.symbol;
             frame.address = frame_info.raw_address;
@@ -1112,19 +1112,31 @@ namespace libdwarf {
 
     CPPTRACE_FORCE_NO_INLINE_FOR_PROFILING
     std::vector<stacktrace_frame> resolve_frames(const std::vector<object_frame>& frames) {
-        std::vector<stacktrace_frame> trace(frames.size(), stacktrace_frame { 0, 0, UINT_LEAST32_MAX, "", "" });
+        std::vector<stacktrace_frame> trace(frames.size(), null_frame);
         static std::mutex mutex;
         // Locking around all libdwarf interaction per https://github.com/davea42/libdwarf-code/discussions/184
         const std::lock_guard<std::mutex> lock(mutex);
         for(const auto& obj_entry : collate_frames(frames, trace)) {
-            const auto& obj_name = obj_entry.first;
-            dwarf_resolver resolver(obj_name);
-            // If there's no debug information it'll mark itself as not ok
-            if(resolver.ok) {
-                for(const auto& entry : obj_entry.second) {
-                    const auto& dlframe = entry.first.get();
-                    auto& frame = entry.second.get();
-                    frame = resolver.resolve_frame(dlframe);
+            try {
+                const auto& obj_name = obj_entry.first;
+                dwarf_resolver resolver(obj_name);
+                // If there's no debug information it'll mark itself as not ok
+                if(resolver.ok) {
+                    for(const auto& entry : obj_entry.second) {
+                        try {
+                            const auto& dlframe = entry.first.get();
+                            auto& frame = entry.second.get();
+                            frame = resolver.resolve_frame(dlframe);
+                        } catch(...) {
+                            if(!should_absorb_trace_exceptions()) {
+                                throw;
+                            }
+                        }
+                    }
+                }
+            } catch(...) {
+                if(!should_absorb_trace_exceptions()) {
+                    throw;
                 }
             }
         }

src/symbols/symbols_with_nothing.cpp

@@ -9,11 +9,11 @@ namespace cpptrace {
 namespace detail {
 namespace nothing {
     std::vector<stacktrace_frame> resolve_frames(const std::vector<uintptr_t>& frames) {
-        return std::vector<stacktrace_frame>(frames.size(), stacktrace_frame { 0, 0, UINT_LEAST32_MAX, "", "" });
+        return std::vector<stacktrace_frame>(frames.size(), null_frame);
     }
 
     std::vector<stacktrace_frame> resolve_frames(const std::vector<object_frame>& frames) {
-        return std::vector<stacktrace_frame>(frames.size(), stacktrace_frame { 0, 0, UINT_LEAST32_MAX, "", "" });
+        return std::vector<stacktrace_frame>(frames.size(), null_frame);
     }
 }
 }

test/demo.cpp

@@ -6,6 +6,7 @@
 #include <string>
 
 void trace() {
+    cpptrace::absorb_trace_exceptions(false);
     cpptrace::generate_trace().print();
 }
 

test/expected/linux.txt

@@ -32,7 +32,7 @@ test/test.cpp||106||void foo<int, int, int, int, int, int, int, int>(int, int, i
 test/test.cpp||106||void foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test/test.cpp||112||function_two(int, float)
 test/test.cpp||118||function_one(int)
-test/test.cpp||124||main
+test/test.cpp||125||main
 ./csu/../sysdeps/nptl/libc_start_call_main.h||58||__libc_start_call_main
 ./csu/../csu/libc-start.c||392||__libc_start_main_impl
 ./test||0||

test/expected/macos.clang.txt

@@ -32,7 +32,7 @@ test/test.cpp||106||void foo<int, int, int, int, int, int, int, int>(int, int, i
 test/test.cpp||106||void foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test/test.cpp||112||function_two(int, float)
 test/test.cpp||118||function_one(int)
-test/test.cpp||124||main
+test/test.cpp||125||main
 ./csu/../sysdeps/nptl/libc_start_call_main.h||58||__libc_start_call_main
 ./csu/../csu/libc-start.c||392||__libc_start_main_impl
 ./test||0||

test/expected/macos.gcc.addr2line.txt

@@ -32,7 +32,7 @@ test/test.cpp||106||void foo<int, int, int, int, int, int, int, int>(int, int, i
 test/test.cpp||106||void foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test/test.cpp||112||function_two(int, float)
 test/test.cpp||118||function_one(int)
-test/test.cpp||124||main
+test/test.cpp||125||main
 ./csu/../sysdeps/nptl/libc_start_call_main.h||58||__libc_start_call_main
 ./csu/../csu/libc-start.c||392||__libc_start_main_impl
 ./test||0||

test/expected/macos.gcc.txt

@@ -32,7 +32,7 @@ test/test.cpp||106||void foo<int, int, int, int, int, int, int, int>(int, int, i
 test/test.cpp||106||void foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test/test.cpp||112||function_two(int, float)
 test/test.cpp||118||function_one(int)
-test/test.cpp||124||main
+test/test.cpp||125||main
 ./csu/../sysdeps/nptl/libc_start_call_main.h||58||__libc_start_call_main
 ./csu/../csu/libc-start.c||392||__libc_start_main_impl
 ./test||0||

test/expected/windows.gcc.txt

@@ -32,7 +32,7 @@ test/test.cpp||106||void foo<int, int, int, int, int, int, int, int>(int, int, i
 test/test.cpp||106||void foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test/test.cpp||112||function_two(int, float)
 test/test.cpp||118||function_one(int)
-test/test.cpp||124||main
+test/test.cpp||125||main
 C:/M/mingw-w64-crt-git/src/mingw-w64/mingw-w64-crt/crt/crtexe.c||272||__tmainCRTStartup
 C:/M/mingw-w64-crt-git/src/mingw-w64/mingw-w64-crt/crt/crtexe.c||193||mainCRTStartup
 ||0||BaseThreadInitThunk

test/expected/windows.txt

@@ -32,7 +32,7 @@ test\test.cpp||106||foo<int, int, int, int, int, int, int, int>(int, int, int, i
 test\test.cpp||106||foo<int, int, int, int, int, int, int, int, int>(int, int, int, int, int, int, int, int, int, int)
 test\test.cpp||112||function_two(int, float)
 test\test.cpp||118||function_one(int)
-test\test.cpp||124||main()
+test\test.cpp||125||main()
 D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl||79||invoke_main()
 D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl||288||__scrt_common_main_seh()
 D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl||331||__scrt_common_main()

test/test.cpp

@@ -121,6 +121,7 @@ void function_one(int) {
 
 int main() {
     x = 0;
+    cpptrace::absorb_trace_exceptions(false);
     function_one(0);
     x = 0;
 }