Refactor logic in the libdwarf resolver's resolve_frames, pull out trace flattening

Author: jeremy-rifkin

src/symbols/symbols_with_libdwarf.cpp

@@ -1177,6 +1177,41 @@ namespace libdwarf {
         }
     }
 
+    // flatten trace with inlines
+    std::vector<stacktrace_frame> flatten_inlines(const std::vector<frame_with_inlines>& trace) {
+        std::vector<stacktrace_frame> final_trace;
+        for(const auto& entry : trace) {
+            // most recent call first
+            if(!entry.inlines.empty()) {
+                // insert in reverse order
+                final_trace.insert(
+                    final_trace.end(),
+                    std::make_move_iterator(entry.inlines.rbegin()),
+                    std::make_move_iterator(entry.inlines.rend())
+                );
+            }
+            final_trace.push_back(std::move(entry.frame));
+            if(!entry.inlines.empty()) {
+                // rotate line info due to quirk of how dwarf stores this stuff
+                // inclusive range
+                auto begin = final_trace.end() - (1 + entry.inlines.size());
+                auto end = final_trace.end() - 1;
+                auto carry_line = end->line;
+                auto carry_column = end->column;
+                std::string carry_filename = std::move(end->filename);
+                for(auto it = end; it != begin; it--) {
+                    it->line = (it - 1)->line;
+                    it->column = (it - 1)->column;
+                    it->filename = std::move((it - 1)->filename);
+                }
+                begin->line = carry_line;
+                begin->column = carry_column;
+                begin->filename = std::move(carry_filename);
+            }
+        }
+        return final_trace;
+    }
+
     CPPTRACE_FORCE_NO_INLINE_FOR_PROFILING
     std::vector<stacktrace_frame> resolve_frames(const std::vector<object_frame>& frames) {
         std::vector<frame_with_inlines> trace(frames.size(), {null_frame, {}});
@@ -1206,56 +1241,29 @@ namespace libdwarf {
                 if(!should_absorb_trace_exceptions()) {
                     throw;
                 }
-                for(const auto& entry : group.second) {
-                    const auto& dlframe = entry.first.get();
-                    auto& frame = entry.second.get();
-                    frame = {
-                        {
-                            dlframe.raw_address,
-                            dlframe.object_address,
-                            nullable<std::uint32_t>::null(),
-                            nullable<std::uint32_t>::null(),
-                            dlframe.object_path,
-                            "",
-                            false
-                        },
-                        {}
-                    };
-                }
             }
         }
-        // flatten trace with inlines
-        std::vector<stacktrace_frame> final_trace;
-        for(const auto& entry : trace) {
-            // most recent call first
-            if(!entry.inlines.empty()) {
-                // insert in reverse order
-                final_trace.insert(
-                    final_trace.end(),
-                    std::make_move_iterator(entry.inlines.rbegin()),
-                    std::make_move_iterator(entry.inlines.rend())
-                );
-            }
-            final_trace.push_back(std::move(entry.frame));
-            if(!entry.inlines.empty()) {
-                // rotate line info due to quirk of how dwarf stores this stuff
-                // inclusive range
-                auto begin = final_trace.end() - (1 + entry.inlines.size());
-                auto end = final_trace.end() - 1;
-                auto carry_line = end->line;
-                auto carry_column = end->column;
-                std::string carry_filename = std::move(end->filename);
-                for(auto it = end; it != begin; it--) {
-                    it->line = (it - 1)->line;
-                    it->column = (it - 1)->column;
-                    it->filename = std::move((it - 1)->filename);
-                }
-                begin->line = carry_line;
-                begin->column = carry_column;
-                begin->filename = std::move(carry_filename);
+        // fill in basic info for any frames where there were resolution issues
+        for(std::size_t i = 0; i < frames.size(); i++) {
+            const auto& dlframe = frames[i];
+            auto& frame = trace[i];
+            if(frame.frame == null_frame) {
+                frame = {
+                    {
+                        dlframe.raw_address,
+                        dlframe.object_address,
+                        nullable<std::uint32_t>::null(),
+                        nullable<std::uint32_t>::null(),
+                        dlframe.object_path,
+                        "",
+                        false
+                    },
+                    {}
+                };
             }
         }
-        return final_trace;
+        // flatten and finish
+        return flatten_inlines(trace);
     }
 }
 }