[WinEH] Emit prologues and epilogues for funclets

Summary:
32-bit funclets have short prologues that allocate enough stack for the
largest call in the whole function. The runtime saves CSRs for the
funclet. It doesn't restore CSRs after we finally transfer control back
to the parent funciton via a CATCHRET, but that's a separate issue.
32-bit funclets also have to adjust the incoming EBP value, which is
what llvm.x86.seh.recoverframe does in the old model.

64-bit funclets need to spill CSRs as normal. For simplicity, this just
spills the same set of CSRs as the parent function, rather than trying
to compute different CSR sets for the parent function and each funclet.
64-bit funclets also allocate enough stack space for the largest
outgoing call frame, like 32-bit.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12546

llvm-svn: 247092

1 files changed, 14 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
index 547dc4cbdc3..aedac5467c6 100644
--- a/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/WinException.cpp
@@ -473,12 +473,20 @@ void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
           OS.EmitValue(create32bitRef(HT.Handler), 4);
 
         if (shouldEmitPersonality) {
-          MCSymbol *ParentFrameOffset =
-              Asm->OutContext.getOrCreateParentFrameOffsetSymbol(
-                  GlobalValue::getRealLinkageName(HT.Handler->getName()));
-          const MCSymbolRefExpr *ParentFrameOffsetRef = MCSymbolRefExpr::create(
-              ParentFrameOffset, Asm->OutContext);
-          OS.EmitValue(ParentFrameOffsetRef, 4); // ParentFrameOffset
+          if (FuncInfo.CatchHandlerParentFrameObjOffset.empty()) {
+            // With the new IR, this is always 16 + 8 + getMaxCallFrameSize().
+            // Keep this in sync with X86FrameLowering::emitPrologue.
+            int ParentFrameOffset =
+                16 + 8 + MF->getFrameInfo()->getMaxCallFrameSize();
+            OS.EmitIntValue(ParentFrameOffset, 4); // ParentFrameOffset
+          } else {
+            MCSymbol *ParentFrameOffset =
+                Asm->OutContext.getOrCreateParentFrameOffsetSymbol(
+                    GlobalValue::getRealLinkageName(HT.Handler->getName()));
+            const MCSymbolRefExpr *ParentFrameOffsetRef =
+                MCSymbolRefExpr::create(ParentFrameOffset, Asm->OutContext);
+            OS.EmitValue(ParentFrameOffsetRef, 4); // ParentFrameOffset
+          }
         }
       }
     }