Adjust program counters for execinfo and capturestackbacktrace too (#50)

ci/test-all-configs.py

@@ -78,9 +78,7 @@ def output_matches(output: str, params: Tuple[str]):
     expected = [line.strip().split("||") for line in expected.split("\n")]
     output = [line.strip().split("||") for line in output.split("\n")]
 
-    max_line_diff = MAX_LINE_DIFF
+    max_line_diff = 0
-    if "CPPTRACE_UNWIND_WITH_UNWIND" in params or "CPPTRACE_UNWIND_WITH_DBGHELP" in params:
-        max_line_diff = 0
 
     errored = False
 
@@ -136,8 +134,6 @@ def run_test(test_binary, params: Tuple[str]):
         if len(test_stderr) != 0:
             print("stderr:")
             print(test_stderr.decode("utf-8"), end="")
-        print(test_stdout, test_stderr, test.returncode)
-        print(test)
         if output_matches(test_stdout.decode("utf-8"), params):
             print(f"{Fore.GREEN}{Style.BRIGHT}Test succeeded{Style.RESET_ALL}")
             return True

src/unwind/unwind_with_execinfo.cpp

@@ -17,9 +17,13 @@ namespace detail {
         skip++;
         std::vector<void*> addrs(std::min(hard_max_frames, skip + max_depth), nullptr);
         const int n_frames = backtrace(addrs.data(), static_cast<int>(addrs.size())); // thread safe
+        // I hate the copy here but it's the only way that isn't UB
         std::vector<uintptr_t> frames(n_frames - skip, 0);
         for(int i = skip; i < n_frames; i++) {
-            frames[i - skip] = reinterpret_cast<uintptr_t>(addrs[i]);
+            // On x86/x64/arm, as far as I can tell, the frame return address is always one after the call
+            // So we just decrement to get the pc back inside the `call` / `bl`
+            // This is done with _Unwind too but conditionally based on info from _Unwind_GetIPInfo.
+            frames[i - skip] = reinterpret_cast<uintptr_t>(addrs[i]) - 1;
         }
         return frames;
     }

src/unwind/unwind_with_winapi.cpp

@@ -27,9 +27,13 @@ namespace detail {
             addrs.data(),
             NULL
         );
+        // I hate the copy here but it's the only way that isn't UB
         std::vector<uintptr_t> frames(n_frames, 0);
         for(std::size_t i = 0; i < n_frames; i++) {
-            frames[i] = reinterpret_cast<uintptr_t>(addrs[i]);
+            // On x86/x64/arm, as far as I can tell, the frame return address is always one after the call
+            // So we just decrement to get the pc back inside the `call` / `bl`
+            // This is done with _Unwind too but conditionally based on info from _Unwind_GetIPInfo.
+            frames[i] = reinterpret_cast<uintptr_t>(addrs[i]) - 1;
         }
         return frames;
     }