[WinEH] Insert the catchpad return before CSR restoration

x64 catchpads use rax to inform the unwinder where control should go
next.  However, we must initialize rax before the epilogue sequence so
as to not perturb the unwinder.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249910 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86FrameLowering.cpp b/lib/Target/X86/X86FrameLowering.cpp
index f63be63efed7656e19a99abb988bbd4e00b3c1a4..9d20fd7c2a97243333871dc937822e1a7dcdbf2c 100644 (file)
--- a/lib/Target/X86/X86FrameLowering.cpp
+++ b/lib/Target/X86/X86FrameLowering.cpp
@@ -1058,6 +1058,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
   bool NeedsWinCFI =
       IsWin64Prologue && MF.getFunction()->needsUnwindTableEntry();
   bool IsFunclet = isFuncletReturnInstr(MBBI);
+  MachineBasicBlock *RestoreMBB = nullptr;
 
   // Get the number of bytes to allocate from the FrameInfo.
   uint64_t StackSize = MFI->getStackSize();
@@ -1082,7 +1083,7 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
     }
 
     // For 32-bit, create a new block for the restore code.
-    MachineBasicBlock *RestoreMBB = TargetMBB;
+    RestoreMBB = TargetMBB;
     if (STI.is32Bit()) {
       RestoreMBB = MF.CreateMachineBasicBlock(MBB.getBasicBlock());
       MF.insert(TargetMBB, RestoreMBB);
@@ -1092,23 +1093,6 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
       MBBI->getOperand(0).setMBB(RestoreMBB);
     }
 
-    // Fill EAX/RAX with the address of the target block.
-    unsigned ReturnReg = STI.is64Bit() ? X86::RAX : X86::EAX;
-    if (STI.is64Bit()) {
-      // LEA64r RestoreMBB(%rip), %rax
-      BuildMI(MBB, MBBI, DL, TII.get(X86::LEA64r), ReturnReg)
-          .addReg(X86::RIP)
-          .addImm(0)
-          .addReg(0)
-          .addMBB(RestoreMBB)
-          .addReg(0);
-    } else {
-      // MOV32ri $RestoreMBB, %eax
-      BuildMI(MBB, MBBI, DL, TII.get(X86::MOV32ri))
-          .addReg(ReturnReg)
-          .addMBB(RestoreMBB);
-    }
-
     // Pop EBP.
     BuildMI(MBB, MBBI, DL, TII.get(Is64Bit ? X86::POP64r : X86::POP32r),
             MachineFramePtr)
@@ -1161,6 +1145,25 @@ void X86FrameLowering::emitEpilogue(MachineFunction &MF,
   }
   MachineBasicBlock::iterator FirstCSPop = MBBI;
 
+  if (RestoreMBB) {
+    // Fill EAX/RAX with the address of the target block.
+    unsigned ReturnReg = STI.is64Bit() ? X86::RAX : X86::EAX;
+    if (STI.is64Bit()) {
+      // LEA64r RestoreMBB(%rip), %rax
+      BuildMI(MBB, FirstCSPop, DL, TII.get(X86::LEA64r), ReturnReg)
+          .addReg(X86::RIP)
+          .addImm(0)
+          .addReg(0)
+          .addMBB(RestoreMBB)
+          .addReg(0);
+    } else {
+      // MOV32ri $RestoreMBB, %eax
+      BuildMI(MBB, FirstCSPop, DL, TII.get(X86::MOV32ri))
+          .addReg(ReturnReg)
+          .addMBB(RestoreMBB);
+    }
+  }
+
   if (MBBI != MBB.end())
     DL = MBBI->getDebugLoc();
 

diff --git a/test/CodeGen/X86/win-catchpad-csrs.ll b/test/CodeGen/X86/win-catchpad-csrs.ll
index 05a59ac9b6234480296f6a58ea3e8330e5dae35a..5e8c3350bca67ac1839b15859114da25272889d4 100644 (file)
--- a/test/CodeGen/X86/win-catchpad-csrs.ll
+++ b/test/CodeGen/X86/win-catchpad-csrs.ll
@@ -123,6 +123,8 @@ catchendblock:                                    ; preds = %catch,
 ; X64: movq %rdx, 16(%rsp)
 ; X64: pushq %rbp
 ; X64: .seh_pushreg 5
+; X64: pushq %rsi
+; X64: .seh_pushreg 6
 ; X64: subq $32, %rsp
 ; X64: .seh_stackalloc 32
 ; X64: leaq 32(%rdx), %rbp
@@ -131,6 +133,7 @@ catchendblock:                                    ; preds = %catch,
 ; X64: callq f
 ; X64: leaq [[contbb]](%rip), %rax
 ; X64: addq $32, %rsp
+; X64: popq %rsi
 ; X64: popq %rbp
 ; X64: retq