tentzen updated this revision to Diff 256942.
tentzen added a comment.

Remove hard-code name "frame-pointer". 
get the name from 2nd Arg of the _finally().


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D77982/new/

https://reviews.llvm.org/D77982

Files:
  clang/lib/CodeGen/CGException.cpp
  clang/lib/CodeGen/CodeGenFunction.h
  clang/test/CodeGen/windows-seh-filter-inFinally.c

Index: clang/test/CodeGen/windows-seh-filter-inFinally.c
===================================================================
--- /dev/null
+++ clang/test/CodeGen/windows-seh-filter-inFinally.c
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -triple x86_64-windows -fms-extensions -Wno-implicit-function-declaration -S -emit-llvm %s -o - | FileCheck %s
+
+// CHECK: %[[dst:[0-9-]+]] = call i8* @llvm.eh.recoverfp(i8* bitcast (void (i8, i8*)* @"?fin$0@0@main@@" to i8*), i8* %frame_pointer)
+// CHECK-NEXT: %[[dst1:[0-9-]+]] = call i8* @llvm.localrecover(i8* bitcast (void (i8, i8*)* @"?fin$0@0@main@@" to i8*), i8* %[[dst]], i32 0)
+// CHECK-NEXT: %[[dst2:[0-9-]+]] = bitcast i8* %[[dst1]] to i8**
+// CHECK-NEXT: = load i8*, i8** %[[dst2]], align 8
+
+int
+main(int argc, char *argv[])
+{
+    int Counter = 0;
+    //
+    // Try/except within the finally clause of a try/finally.
+    //
+    __try {
+      Counter -= 1;
+    }
+    __finally {
+      __try {
+        Counter += 2;
+        // RtlRaiseStatus(STATUS_INTEGER_OVERFLOW);
+      } __except(Counter) {
+        __try {
+          Counter += 3;
+        }
+        __finally {
+          if (abnormal_termination() == 1) {
+            Counter += 5;
+          }
+        }
+      }
+    }
+    // expect Counter == 9
+    return 1;
+}
+
Index: clang/lib/CodeGen/CodeGenFunction.h
===================================================================
--- clang/lib/CodeGen/CodeGenFunction.h
+++ clang/lib/CodeGen/CodeGenFunction.h
@@ -367,6 +367,9 @@
   CodeGenModule &CGM;  // Per-module state.
   const TargetInfo &Target;
 
+  // For EH/SEH outlined funclets, this field points to parent's CGF
+  CodeGenFunction *ParentCGF = nullptr;
+
   typedef std::pair<llvm::Value *, llvm::Value *> ComplexPairTy;
   LoopInfoStack LoopStack;
   CGBuilderTy Builder;
Index: clang/lib/CodeGen/CGException.cpp
===================================================================
--- clang/lib/CodeGen/CGException.cpp
+++ clang/lib/CodeGen/CGException.cpp
@@ -1794,6 +1794,46 @@
     llvm::Constant *ParentI8Fn =
         llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
     ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
+
+    // if the parent is a _finally, the passed-in ParentFP is the FP
+    // of parent _finally, not Establisher's FP (FP of outermost function).
+    // Establkisher FP is 2nd paramenter passed into parent _finally.
+    // Fortunately, it's always saved in parent's frame. The following
+    // code retrieves it, and escapes it so that spill instruction won't be
+    // optimized away.
+    if (ParentCGF.ParentCGF != nullptr) {
+      // Locate and escape Parent's frame_pointer.addr alloca
+      llvm::Function *Fn = ParentCGF.CurFn;
+      StringRef Name = Fn->getArg(1)->getName();
+      llvm::AllocaInst *FramePtrAddrAlloca = nullptr;
+      for (llvm::Instruction &I : ParentCGF.CurFn->getEntryBlock()) {
+        llvm::AllocaInst *II = dyn_cast<llvm::AllocaInst>(&I);
+        if (II && II->getName().startswith(Name)) {
+          FramePtrAddrAlloca = II;
+          break;
+        }
+      }
+      assert(FramePtrAddrAlloca);
+      auto InsertPair = ParentCGF.EscapedLocals.insert(
+          std::make_pair(FramePtrAddrAlloca, ParentCGF.EscapedLocals.size()));
+      int FrameEscapeIdx = InsertPair.first->second;
+
+      // an example of a filter's prolog::
+      // %0 = call i8* @llvm.eh.recoverfp(bitcast(@"?fin$0@0@main@@"),..)
+      // %1 = call i8* @llvm.localrecover(bitcast(@"?fin$0@0@main@@"),..)
+      // %2 = bitcast i8* %1 to i8**
+      // %3 = load i8*, i8* *%2, align 8
+      //   ==> %3 is the frame-pointer of outermost host function
+      llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
+          &CGM.getModule(), llvm::Intrinsic::localrecover);
+      llvm::Constant *ParentI8Fn =
+          llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
+      ParentFP = Builder.CreateCall(
+          FrameRecoverFn, {ParentI8Fn, ParentFP,
+                           llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
+      ParentFP = Builder.CreateBitCast(ParentFP, CGM.VoidPtrPtrTy);
+      ParentFP = Builder.CreateLoad(Address(ParentFP, getPointerAlign()));
+    }
   }
 
   // Create llvm.localrecover calls for all captures.
@@ -1992,6 +2032,7 @@
 
 void CodeGenFunction::EnterSEHTryStmt(const SEHTryStmt &S) {
   CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
+  HelperCGF.ParentCGF = this;
   if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
     // Outline the finally block.
     llvm::Function *FinallyFunc =
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