[clang-tools-extra] [clang-tidy] Improve `bugprone-exception-escape`: add stacktrace of escaped exception (PR #134375)

[Congcong Cai via cfe-commits]

================
@@ -80,13 +78,47 @@ void ExceptionEscapeCheck::check(const MatchFinder::MatchResult &Result) {
   if (!MatchedDecl)
     return;
 
-  if (Tracer.analyze(MatchedDecl).getBehaviour() ==
-      utils::ExceptionAnalyzer::State::Throwing)
-    // FIXME: We should provide more information about the exact location where
-    // the exception is thrown, maybe the full path the exception escapes
-    diag(MatchedDecl->getLocation(), "an exception may be thrown in function "
-                                     "%0 which should not throw exceptions")
-        << MatchedDecl;
+  const utils::ExceptionAnalyzer::ExceptionInfo Info =
+      Tracer.analyze(MatchedDecl);
+
+  if (Info.getBehaviour() != utils::ExceptionAnalyzer::State::Throwing) {
+    return;
+  }
+
+  diag(MatchedDecl->getLocation(), "an exception may be thrown in function "
+                                   "%0 which should not throw exceptions")
+      << MatchedDecl;
+
+  const utils::ExceptionAnalyzer::ExceptionInfo::ThrowInfo ThrowInfo =
+      Info.getExceptions().begin()->getSecond();
+
+  if (ThrowInfo.Loc.isInvalid()) {
+    return;
+  }
+
+  const utils::ExceptionAnalyzer::CallStack &Stack = ThrowInfo.Stack;
+  diag(ThrowInfo.Loc,
+       "frame #0: unhandled exception may be thrown in function %0 here",
+       DiagnosticIDs::Note)
+      << Stack.back().first;
+
+  size_t FrameNo = 1;
+  for (auto CurrIt = ++Stack.rbegin(), PrevIt = Stack.rbegin();
+       CurrIt != Stack.rend(); ++CurrIt, ++PrevIt) {
+    const FunctionDecl *CurrFunction = CurrIt->first;
+    const FunctionDecl *PrevFunction = PrevIt->first;
+    const SourceLocation PrevLocation = PrevIt->second;
+    if (PrevLocation.isValid()) {
+      diag(PrevLocation, "frame #%0: function %1 calls function %2 here",
+           DiagnosticIDs::Note)
+          << FrameNo << CurrFunction << PrevFunction;
+    } else {
+      diag(CurrFunction->getLocation(),
+           "frame #%0: function %1 calls function %2", DiagnosticIDs::Note)
----------------
HerrCai0907 wrote:

```suggestion
           "frame #%0: function '%1' calls function '%2'", DiagnosticIDs::Note)
```

https://github.com/llvm/llvm-project/pull/134375