Add cache mode config

README.md

@@ -224,10 +224,27 @@ The library makes an attempt to fail silently and continue during trace generati
 `cpptrace::absorb_trace_exceptions` can be used to configure whether these exceptions are absorbed silently internally
 or wether they're rethrown to the caller.
 
+`cpptrace::experimental::set_cache_mode` can be used to control time-memory tradeoffs within the library. By default
+speed is prioritized. If using this function, set the cache mode at the very start of your program before any traces are
+performed.
+
 ```cpp
 namespace cpptrace {
     std::string demangle(const std::string& name);
     void absorb_trace_exceptions(bool absorb);
+
+    enum class cache_mode {
+        // Only minimal lookup tables
+        prioritize_memory,
+        // Build lookup tables but don't keep them around between trace calls
+        hybrid,
+        // Build lookup tables as needed
+        prioritize_speed
+    };
+
+    namespace experimental {
+        void set_cache_mode(cache_mode mode);
+    }
 }
 ```
 

include/cpptrace/cpptrace.hpp

@@ -130,8 +130,22 @@ namespace cpptrace {
     CPPTRACE_API std::string demangle(const std::string& name);
     CPPTRACE_API void absorb_trace_exceptions(bool absorb);
 
+    enum class cache_mode {
+        // Only minimal lookup tables
+        prioritize_memory,
+        // Build lookup tables but don't keep them around between trace calls
+        hybrid,
+        // Build lookup tables as needed
+        prioritize_speed
+    };
+
+    namespace experimental {
+        CPPTRACE_API void set_cache_mode(cache_mode mode);
+    }
+
     namespace detail {
         CPPTRACE_API bool should_absorb_trace_exceptions();
+        CPPTRACE_API enum cache_mode get_cache_mode();
     }
 
     class exception : public std::exception {

src/cpptrace.cpp

@@ -26,10 +26,6 @@
 #define CYAN    ESC "36m"
 
 namespace cpptrace {
-    namespace detail {
-        std::atomic_bool absorb_trace_exceptions(true);
-    }
-
     CPPTRACE_FORCE_NO_INLINE CPPTRACE_API
     raw_trace raw_trace::current(std::uint_least32_t skip) {
         return generate_raw_trace(skip + 1);
@@ -316,13 +312,28 @@ namespace cpptrace {
         return detail::demangle(name);
     }
 
+    namespace detail {
+        std::atomic_bool absorb_trace_exceptions(true);
+        std::atomic<enum cache_mode> cache_mode(cache_mode::prioritize_speed);
+    }
+
     CPPTRACE_API void absorb_trace_exceptions(bool absorb) {
         detail::absorb_trace_exceptions = absorb;
     }
 
+    namespace experimental {
+        CPPTRACE_API void set_cache_mode(cache_mode mode) {
+            detail::cache_mode = mode;
+        }
+    }
+
     namespace detail {
         CPPTRACE_API bool should_absorb_trace_exceptions() {
-            return detail::absorb_trace_exceptions;
+            return absorb_trace_exceptions;
+        }
+
+        CPPTRACE_API enum cache_mode get_cache_mode() {
+            return cache_mode;
         }
     }
 }

src/symbols/symbols_with_dbghelp.cpp

@@ -398,7 +398,13 @@ namespace dbghelp {
         // TODO: When does this need to be called? Can it be moved to the symbolizer?
         SymSetOptions(SYMOPT_ALLOW_ABSOLUTE_SYMBOLS);
         HANDLE proc = GetCurrentProcess();
-        get_syminit_manager().init(proc);
+        if(get_cache_mode() == cache_mode::prioritize_speed) {
+            get_syminit_manager().init(proc);
+        } else {
+            if(!SymInitialize(proc, NULL, TRUE)) {
+                throw std::logic_error("Cpptrace SymInitialize failed");
+            }
+        }
         for(const auto frame : frames) {
             try {
                 trace.push_back(resolve_frame(proc, frame));
@@ -409,6 +415,11 @@ namespace dbghelp {
                 trace.push_back(null_frame);
             }
         }
+        if(get_cache_mode() != cache_mode::prioritize_speed) {
+            if(!SymCleanup(proc)) {
+                throw std::logic_error("Cpptrace SymCleanup failed");
+            }
+        }
         return trace;
     }
 }

src/symbols/symbols_with_libdwarf.cpp

@@ -575,7 +575,7 @@ namespace libdwarf {
                 // Check for .debug_aranges for fast lookup
                 wrap(dwarf_get_aranges, dbg, &aranges, &arange_count);
             }
-            if(ok && !aranges) {
+            if(ok && !aranges && get_cache_mode() != cache_mode::prioritize_memory) {
                 walk_compilation_units([this] (const die_object& cu_die) {
                     Dwarf_Half offset_size = 0;
                     Dwarf_Half dwversion = 0;
@@ -839,39 +839,44 @@ namespace libdwarf {
             Dwarf_Half dwversion,
             stacktrace_frame& frame
         ) {
-            auto off = cu_die.get_global_offset();
-            auto it = subprograms_cache.find(off);
-            if(it == subprograms_cache.end()) {
-                std::vector<subprogram_entry> vec;
-                preprocess_subprograms(cu_die, dwversion, vec);
-                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);
-            }
-            auto& vec = it->second;
-            auto vec_it = std::lower_bound(
-                vec.begin(),
-                vec.end(),
-                pc,
-                [] (const subprogram_entry& entry, Dwarf_Addr pc) {
-                    return entry.low < pc;
-                }
-            );
-            // vec_it is first >= pc
-            // we want first <= pc
-            if(vec_it != vec.begin()) {
-                vec_it--;
-            }
-            // If the vector has been empty this can happen
-            if(vec_it != vec.end()) {
-                //vec_it->die.print();
-                if(vec_it->die.pc_in_die(dwversion, pc)) {
-                    retrieve_symbol_for_subprogram(vec_it->die, dwversion, frame);
-                }
+            if(get_cache_mode() == cache_mode::prioritize_memory) {
+                retrieve_symbol_walk(cu_die, pc, dwversion, frame);
             } else {
-                ASSERT(vec.size() == 0, "Vec should be empty?");
+                auto off = cu_die.get_global_offset();
+                auto it = subprograms_cache.find(off);
+                if(it == subprograms_cache.end()) {
+                    // TODO: Refactor. Do the sort in the preprocess function and return the vec directly.
+                    std::vector<subprogram_entry> vec;
+                    preprocess_subprograms(cu_die, dwversion, vec);
+                    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);
+                }
+                auto& vec = it->second;
+                auto vec_it = std::lower_bound(
+                    vec.begin(),
+                    vec.end(),
+                    pc,
+                    [] (const subprogram_entry& entry, Dwarf_Addr pc) {
+                        return entry.low < pc;
+                    }
+                );
+                // vec_it is first >= pc
+                // we want first <= pc
+                if(vec_it != vec.begin()) {
+                    vec_it--;
+                }
+                // If the vector has been empty this can happen
+                if(vec_it != vec.end()) {
+                    //vec_it->die.print();
+                    if(vec_it->die.pc_in_die(dwversion, pc)) {
+                        retrieve_symbol_for_subprogram(vec_it->die, dwversion, frame);
+                    }
+                } else {
+                    ASSERT(vec.size() == 0, "Vec should be empty?");
+                }
             }
         }
 
@@ -998,7 +1003,7 @@ namespace libdwarf {
                     retrieve_symbol(cu_die, pc, dwversion, frame);
                 }
             } else {
-                if(false) { // TODO: Proper condition
+                if(get_cache_mode() == cache_mode::prioritize_memory) {
                     // walk for the cu and go from there
                     walk_compilation_units([this, pc, &frame] (const die_object& cu_die) {
                         Dwarf_Half offset_size = 0;

src/unwind/unwind_with_dbghelp.cpp

@@ -89,7 +89,13 @@ namespace detail {
         //
         HANDLE proc = GetCurrentProcess();
         HANDLE thread = GetCurrentThread();
-        get_syminit_manager().init(proc);
+        if(get_cache_mode() == cache_mode::prioritize_speed) {
+            get_syminit_manager().init(proc);
+        } else {
+            if(!SymInitialize(proc, NULL, TRUE)) {
+                throw std::logic_error("Cpptrace SymInitialize failed");
+            }
+        }
         while(trace.size() < max_depth) {
             if(
                 !StackWalk64(
@@ -122,6 +128,11 @@ namespace detail {
                 break;
             }
         }
+        if(get_cache_mode() != cache_mode::prioritize_speed) {
+            if(!SymCleanup(proc)) {
+                throw std::logic_error("Cpptrace SymCleanup failed");
+            }
+        }
         return trace;
     }
 }