From b0d280a58878b855dacbc1848d220fed4484b708 Mon Sep 17 00:00:00 2001
From: Joseph Tremoulet <jotrem@microsoft.com>
Date: Thu, 5 Nov 2015 02:20:07 +0000
Subject: [PATCH] [WinEH] Fix establisher param reg in CLR funclets

Summary:
The CLR's personality routine passes the pointer to the establisher frame
in RCX, not RDX.

Reviewers: pgavlin, majnemer, rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14343

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252135 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86FrameLowering.cpp | 29 ++++++++++++++++++++---------
 test/CodeGen/WinEH/wineh-coreclr.ll |  8 ++++++++
 2 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index ee866fa45c3..ae4cc77fcc9 100644
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -18,6 +18,7 @@
 #include "X86Subtarget.h"
 #include "X86TargetMachine.h"
 #include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/CodeGen/MachineFrameInfo.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -624,6 +625,9 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
   uint64_t MaxAlign = calculateMaxStackAlign(MF); // Desired stack alignment.
   uint64_t StackSize = MFI->getStackSize();    // Number of bytes to allocate.
   bool IsFunclet = MBB.isEHFuncletEntry();
+  bool IsClrFunclet =
+      IsFunclet &&
+      classifyEHPersonality(Fn->getPersonalityFn()) == EHPersonality::CoreCLR;
   bool HasFP = hasFP(MF);
   bool IsWin64CC = STI.isCallingConvWin64(Fn->getCallingConv());
   bool IsWin64Prologue = MF.getTarget().getMCAsmInfo()->usesWindowsCFI();
@@ -701,13 +705,20 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
   uint64_t NumBytes = 0;
   int stackGrowth = -SlotSize;
 
-  unsigned RDX = Uses64BitFramePtr ? X86::RDX : X86::EDX;
-  if (IsWin64Prologue && IsFunclet) {
-    // Immediately spill RDX into the home slot. The runtime cares about this.
+  // Find the funclet establisher parameter
+  unsigned Establisher = X86::NoRegister;
+  if (IsClrFunclet)
+    Establisher = Uses64BitFramePtr ? X86::RCX : X86::ECX;
+  else if (IsFunclet)
+    Establisher = Uses64BitFramePtr ? X86::RDX : X86::EDX;
+
+  if (IsWin64Prologue && IsFunclet & !IsClrFunclet) {
+    // Immediately spill establisher into the home slot.
+    // The runtime cares about this.
     // MOV64mr %rdx, 16(%rsp)
     unsigned MOVmr = Uses64BitFramePtr ? X86::MOV64mr : X86::MOV32mr;
     addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(MOVmr)), StackPtr, true, 16)
-        .addReg(RDX)
+        .addReg(Establisher)
         .setMIFlag(MachineInstr::FrameSetup);
   }
 
@@ -911,16 +922,16 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF,
   int SEHFrameOffset = 0;
   if (IsWin64Prologue && HasFP) {
     // Set RBP to a small fixed offset from RSP. In the funclet case, we base
-    // this calculation on the incoming RDX, which holds the value of RSP from
-    // the parent frame at the end of the prologue.
-    unsigned SPOrRDX = !IsFunclet ? StackPtr : RDX;
+    // this calculation on the incoming establisher, which holds the value of
+    // RSP from the parent frame at the end of the prologue.
+    unsigned SPOrEstablisher = IsFunclet ? Establisher : StackPtr;
     SEHFrameOffset = calculateSetFPREG(ParentFrameNumBytes);
     if (SEHFrameOffset)
       addRegOffset(BuildMI(MBB, MBBI, DL, TII.get(X86::LEA64r), FramePtr),
-                   SPOrRDX, false, SEHFrameOffset);
+                   SPOrEstablisher, false, SEHFrameOffset);
     else
       BuildMI(MBB, MBBI, DL, TII.get(X86::MOV64rr), FramePtr)
-          .addReg(SPOrRDX);
+          .addReg(SPOrEstablisher);
 
     // If this is not a funclet, emit the CFI describing our frame pointer.
     if (NeedsWinCFI && !IsFunclet)
diff --git a/test/CodeGen/WinEH/wineh-coreclr.ll b/test/CodeGen/WinEH/wineh-coreclr.ll
index 56675fefae7..f5e046aa01c 100644
--- a/test/CodeGen/WinEH/wineh-coreclr.ll
+++ b/test/CodeGen/WinEH/wineh-coreclr.ll
@@ -50,6 +50,8 @@ catch1.pad:
   %catch1 = catchpad [i32 1]
     to label %catch1.body unwind label %catch2.pad
 catch1.body:
+; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
+;                     ^ establisher frame pointer passed in rcx
 ; CHECK: .seh_endprologue
 ; CHECK: [[L_before_f3:.+]]:
 ; CHECK-NEXT: movl $3, %ecx
@@ -64,6 +66,8 @@ catch2.pad:
   %catch2 = catchpad [i32 2]
     to label %catch2.body unwind label %catch.end
 catch2.body:
+; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
+;                     ^ establisher frame pointer passed in rcx
 ; CHECK: .seh_endprologue
 ; CHECK: [[L_before_f4:.+]]:
 ; CHECK-NEXT: movl $4, %ecx
@@ -82,6 +86,8 @@ try_in_catch:
 fault.pad:
 ; CHECK: .seh_proc [[L_fault:[^ ]+]]
   %fault = cleanuppad [i32 undef]
+; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
+;                     ^ establisher frame pointer passed in rcx
 ; CHECK: .seh_endprologue
 ; CHECK: [[L_before_f6:.+]]:
 ; CHECK-NEXT: movl $6, %ecx
@@ -103,6 +109,8 @@ finally.clone:
 finally.pad:
 ; CHECK: .seh_proc [[L_finally:[^ ]+]]
   %finally = cleanuppad []
+; CHECK: leaq {{[0-9]+}}(%rcx), %rbp
+;                     ^ establisher frame pointer passed in rcx
 ; CHECK: .seh_endprologue
 ; CHECK: [[L_before_f7:.+]]:
 ; CHECK-NEXT: movl $7, %ecx
-- 
2.34.1