[llvm-commits] [llvm] r141859 - in /llvm/trunk: lib/Target/X86/X86FrameLowering.cpp test/CodeGen/X86/segmented-stacks.ll

[Bill Wendling]

Should have mentioned that the patch was by Sanjoy Das!

-bw

On Oct 13, 2011, at 1:24 AM, Bill Wendling wrote:

> Author: void
> Date: Thu Oct 13 03:24:19 2011
> New Revision: 141859
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=141859&view=rev
> Log:
> More closely follow libgcc, which has code after the `ret' instruction to
> release the stack segment and reset the stack pointer. Place the code in its own
> MBB to make the verifier happy.
> 
> Modified:
>    llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
>    llvm/trunk/test/CodeGen/X86/segmented-stacks.ll
> 
> Modified: llvm/trunk/lib/Target/X86/X86FrameLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FrameLowering.cpp?rev=141859&r1=141858&r2=141859&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86FrameLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86FrameLowering.cpp Thu Oct 13 03:24:19 2011
> @@ -1336,15 +1336,28 @@
>   if (Is64Bit)
>     IsNested = HasNestArgument(&MF);
> 
> +  // The MOV R10, RAX needs to be in a different block, since the RET we emit in
> +  // allocMBB needs to be last (terminating) instruction.
> +  MachineBasicBlock *restoreR10MBB = NULL;
> +  if (IsNested)
> +    restoreR10MBB = MF.CreateMachineBasicBlock();
> +
>   for (MachineBasicBlock::livein_iterator i = prologueMBB.livein_begin(),
>          e = prologueMBB.livein_end(); i != e; i++) {
>     allocMBB->addLiveIn(*i);
>     checkMBB->addLiveIn(*i);
> +
> +    if (IsNested)
> +      restoreR10MBB->addLiveIn(*i);
>   }
> 
> -  if (IsNested)
> +  if (IsNested) {
>     allocMBB->addLiveIn(X86::R10);
> +    restoreR10MBB->addLiveIn(X86::RAX);
> +  }
> 
> +  if (IsNested)
> +    MF.push_front(restoreR10MBB);
>   MF.push_front(allocMBB);
>   MF.push_front(checkMBB);
> 
> @@ -1414,13 +1427,19 @@
>   if (!Is64Bit)
>     BuildMI(allocMBB, DL, TII.get(X86::ADD32ri), X86::ESP).addReg(X86::ESP)
>       .addImm(8);
> +  BuildMI(allocMBB, DL, TII.get(X86::RET));
> 
> -  if (Is64Bit && IsNested)
> -    BuildMI(allocMBB, DL, TII.get(X86::MOV64rr), X86::R10).addReg(X86::RAX);
> +  if (IsNested)
> +    BuildMI(restoreR10MBB, DL, TII.get(X86::MOV64rr), X86::R10)
> +      .addReg(X86::RAX);
> 
> -  BuildMI(allocMBB, DL, TII.get(X86::RET));
> +  if (IsNested) {
> +    allocMBB->addSuccessor(restoreR10MBB);
> +    restoreR10MBB->addSuccessor(&prologueMBB);
> +  } else {
> +    allocMBB->addSuccessor(&prologueMBB);
> +  }
> 
> -  allocMBB->addSuccessor(&prologueMBB);
>   checkMBB->addSuccessor(allocMBB);
>   checkMBB->addSuccessor(&prologueMBB);
> 
> 
> Modified: llvm/trunk/test/CodeGen/X86/segmented-stacks.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/segmented-stacks.ll?rev=141859&r1=141858&r2=141859&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/segmented-stacks.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/segmented-stacks.ll Thu Oct 13 03:24:19 2011
> @@ -81,7 +81,7 @@
> ; X64-NEXT: movabsq $0, %r10
> ; X64-NEXT: movabsq $0, %r11
> ; X64-NEXT: callq __morestack
> -; X64-NEXT: movq %rax, %r10
> ; X64-NEXT: ret
> +; X64:      movq %rax, %r10
> 
> }
> 
> 
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