[clang] [codegen] Emit cleanups for branch in stmt-expr and coro suspensions (PR #85398)

[Utkarsh Saxena via cfe-commits]

https://github.com/usx95 created https://github.com/llvm/llvm-project/pull/85398

Promotes some EHOnly cleanups to NormalAndEHCleanups to make sure these are emitted if we see a branch inside an expression (through statement expressions or coroutine suspensions).
These are usually deactivated after the full expression and destroyed later as part of the destructor of aggregate/array being constructed.

Also fixes the emission of deactivated but branch-throughed normal cleanups.

>From 0654f624b3b60026398e8b0168623a85e3129630 Mon Sep 17 00:00:00 2001
From: Utkarsh Saxena <usx at google.com>
Date: Fri, 15 Mar 2024 13:19:36 +0000
Subject: [PATCH] [codegen] Emit cleanups for branch in stmt-expr and coro
 suspensions

---
 clang/lib/CodeGen/CGCleanup.cpp |  7 +++++--
 clang/lib/CodeGen/CGExprAgg.cpp | 13 +++++++------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp
index f87caf050eeaa7..c22d4da0fefc3c 100644
--- a/clang/lib/CodeGen/CGCleanup.cpp
+++ b/clang/lib/CodeGen/CGCleanup.cpp
@@ -694,7 +694,8 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
 
   // - whether there's a fallthrough
   llvm::BasicBlock *FallthroughSource = Builder.GetInsertBlock();
-  bool HasFallthrough = (FallthroughSource != nullptr && IsActive);
+  bool HasFallthrough =
+      FallthroughSource != nullptr && (IsActive || HasExistingBranches);
 
   // Branch-through fall-throughs leave the insertion point set to the
   // end of the last cleanup, which points to the current scope.  The
@@ -719,7 +720,9 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
 
   // If we have a prebranched fallthrough into an inactive normal
   // cleanup, rewrite it so that it leads to the appropriate place.
-  if (Scope.isNormalCleanup() && HasPrebranchedFallthrough && !IsActive) {
+  if (Scope.isNormalCleanup() && HasPrebranchedFallthrough &&
+      !RequiresNormalCleanup) {
+    assert(!IsActive);
     llvm::BasicBlock *prebranchDest;
 
     // If the prebranch is semantically branching through the next
diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 5190b22bcc1622..7e62599089b8df 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -15,6 +15,7 @@
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "ConstantEmitter.h"
+#include "EHScopeStack.h"
 #include "TargetInfo.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
@@ -1389,15 +1390,15 @@ AggExprEmitter::VisitLambdaExpr(LambdaExpr *E) {
     if (QualType::DestructionKind DtorKind =
             CurField->getType().isDestructedType()) {
       assert(LV.isSimple());
-      if (CGF.needsEHCleanup(DtorKind)) {
+      if (DtorKind) {
         if (!CleanupDominator)
           CleanupDominator = CGF.Builder.CreateAlignedLoad(
               CGF.Int8Ty,
               llvm::Constant::getNullValue(CGF.Int8PtrTy),
               CharUnits::One()); // placeholder
 
-        CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), CurField->getType(),
-                        CGF.getDestroyer(DtorKind), false);
+        CGF.pushDestroy(NormalAndEHCleanup, LV.getAddress(CGF),
+                        CurField->getType(), CGF.getDestroyer(DtorKind), false);
         Cleanups.push_back(CGF.EHStack.stable_begin());
       }
     }
@@ -1806,9 +1807,9 @@ void AggExprEmitter::VisitCXXParenListOrInitListExpr(
     if (QualType::DestructionKind dtorKind
           = field->getType().isDestructedType()) {
       assert(LV.isSimple());
-      if (CGF.needsEHCleanup(dtorKind)) {
-        CGF.pushDestroy(EHCleanup, LV.getAddress(CGF), field->getType(),
-                        CGF.getDestroyer(dtorKind), false);
+      if (dtorKind) {
+        CGF.pushDestroy(NormalAndEHCleanup, LV.getAddress(CGF),
+                        field->getType(), CGF.getDestroyer(dtorKind), false);
         addCleanup(CGF.EHStack.stable_begin());
         pushedCleanup = true;
       }