[SEH] Pass the frame pointer from SEH finally to finally functions

Pass the frame pointer that the first finally block receives onto the nested
finally block, instead of generating it using localaddr.

Differential Revision: https://reviews.llvm.org/D56463

llvm-svn: 351302

2 files changed, 36 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGException.cpp b/clang/lib/CodeGen/CGException.cpp
index dd4298cc57f..5756e13d262 100644
--- a/clang/lib/CodeGen/CGException.cpp
+++ b/clang/lib/CodeGen/CGException.cpp
@@ -1627,8 +1627,16 @@ struct PerformSEHFinally final : EHScopeStack::Cleanup {
 
     // Compute the two argument values.
     QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
-    llvm::Value *LocalAddrFn = CGM.getIntrinsic(llvm::Intrinsic::localaddress);
-    llvm::Value *FP = CGF.Builder.CreateCall(LocalAddrFn);
+    llvm::Value *FP = nullptr;
+    // If CFG.IsOutlinedSEHHelper is true, then we are within a finally block.
+    if (CGF.IsOutlinedSEHHelper) {
+      FP = &CGF.CurFn->arg_begin()[1];
+    } else {
+      llvm::Value *LocalAddrFn =
+          CGM.getIntrinsic(llvm::Intrinsic::localaddress);
+      FP = CGF.Builder.CreateCall(LocalAddrFn);
+    }
+
     llvm::Value *IsForEH =
         llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
     Args.add(RValue::get(IsForEH), ArgTys[0]);
diff --git a/clang/test/CodeGen/exceptions-seh-nested-finally.c b/clang/test/CodeGen/exceptions-seh-nested-finally.c
new file mode 100644
index 00000000000..7385d18f0cd
--- /dev/null
+++ b/clang/test/CodeGen/exceptions-seh-nested-finally.c
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 %s -triple x86_64-pc-win32 -fms-extensions -emit-llvm -o - \
+// RUN:         | FileCheck %s
+// RUN: %clang_cc1 %s -triple i686-pc-win32 -fms-extensions -emit-llvm -o - \
+// RUN:         | FileCheck %s
+// RUN: %clang_cc1 %s -triple aarch64-windows -fms-extensions -emit-llvm -o - \
+// RUN:         | FileCheck %s
+
+// Check that the first finally block passes the enclosing function's frame
+// pointer to the second finally block, instead of generating it via localaddr.
+
+// CHECK-LABEL: define internal void @"?fin$0@0@main@@"({{i8( zeroext)?}} %abnormal_termination, i8* %frame_pointer)
+// CHECK: call void @"?fin$1@0@main@@"({{i8( zeroext)?}} 0, i8* %frame_pointer)
+int
+main() {
+  int Check = 0;
+  __try {
+    Check = 3;
+  } __finally {
+    __try {
+      Check += 2;
+    } __finally {
+      Check += 4;
+    }
+  }
+  return Check;
+}