[llvm] r194676 - Minor extension to llvm.experimental.patchpoint: don't require a call.

[Andrew Trick]

On Nov 14, 2013, at 11:35 PM, Eric Christopher <echristo at gmail.com> wrote:

> On Thu, Nov 14, 2013 at 10:09 PM, Andrew Trick <atrick at apple.com> wrote:
>> Public bots? I can’t find any.
>> 
> 
> http://lab.llvm.org:8011/builders/clang-atom-d525-fedora-rel/builds/37
> 
> as an example.

I think that was caused by a different checkin. It was a cpu dependency (lea vs sub). Fixed in r194788.
-Andy

> 
> -eric
> 
>> Private bots? In what way are they breaking?
>> 
>> -Andy
>> 
>> On Nov 14, 2013, at 9:59 PM, Eric Christopher <echristo at gmail.com> wrote:
>> 
>>> Hi Andy,
>>> 
>>> This appears to be breaking a lot of bots...
>>> 
>>> -eric
>>> 
>>> On Wed, Nov 13, 2013 at 10:54 PM, Andrew Trick <atrick at apple.com> wrote:
>>>> Author: atrick
>>>> Date: Thu Nov 14 00:54:10 2013
>>>> New Revision: 194676
>>>> 
>>>> URL: http://llvm.org/viewvc/llvm-project?rev=194676&view=rev
>>>> Log:
>>>> Minor extension to llvm.experimental.patchpoint: don't require a call.
>>>> 
>>>> If a null call target is provided, don't emit a dummy call. This
>>>> allows the runtime to reserve as little nop space as it needs without
>>>> the requirement of emitting a call.
>>>> 
>>>> Modified:
>>>>   llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>>>>   llvm/trunk/lib/Target/X86/X86MCInstLower.cpp
>>>>   llvm/trunk/test/CodeGen/X86/patchpoint.ll
>>>> 
>>>> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=194676&r1=194675&r2=194676&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
>>>> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Thu Nov 14 00:54:10 2013
>>>> @@ -6826,7 +6826,7 @@ void SelectionDAGBuilder::visitStackmap(
>>>> /// \brief Lower llvm.experimental.patchpoint directly to its target opcode.
>>>> void SelectionDAGBuilder::visitPatchpoint(const CallInst &CI) {
>>>>  // void|i64 @llvm.experimental.patchpoint.void|i64(i32 <id>,
>>>> -  //                                                 i32 <numNopBytes>,
>>>> +  //                                                 i32 <numBytes>,
>>>>  //                                                 i8* <target>,
>>>>  //                                                 i32 <numArgs>,
>>>>  //                                                 [Args...],
>>>> 
>>>> Modified: llvm/trunk/lib/Target/X86/X86MCInstLower.cpp
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86MCInstLower.cpp?rev=194676&r1=194675&r2=194676&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/lib/Target/X86/X86MCInstLower.cpp (original)
>>>> +++ llvm/trunk/lib/Target/X86/X86MCInstLower.cpp Thu Nov 14 00:54:10 2013
>>>> @@ -765,6 +765,8 @@ static void LowerSTACKMAP(MCStreamer &Ou
>>>>    OutStreamer.EmitInstruction(MCInstBuilder(X86::NOOP));
>>>> }
>>>> 
>>>> +// Lower a patchpoint of the form:
>>>> +// [<def>], <id>, <numBytes>, <target>, <numArgs>
>>>> static void LowerPATCHPOINT(MCStreamer &OutStreamer,
>>>>                            X86MCInstLower &MCInstLowering,
>>>>                            StackMaps &SM,
>>>> @@ -813,17 +815,20 @@ static void LowerPATCHPOINT(MCStreamer &
>>>>                    getStackMapEndMOP(MI.operands_begin(), MI.operands_end()),
>>>>                    isAnyRegCC && hasDef);
>>>> 
>>>> -  // Emit MOV to materialize the target address and the CALL to target.
>>>> -  // This is encoded with 12-13 bytes, depending on which register is used.
>>>> -  // We conservatively assume that it is 12 bytes and emit in worst case one
>>>> -  // extra NOP byte.
>>>> -  unsigned EncodedBytes = 12;
>>>> -  OutStreamer.EmitInstruction(MCInstBuilder(X86::MOV64ri)
>>>> -                              .addReg(MI.getOperand(ScratchIdx).getReg())
>>>> -                              .addImm(MI.getOperand(StartIdx + 2).getImm()));
>>>> -  OutStreamer.EmitInstruction(MCInstBuilder(X86::CALL64r)
>>>> -                              .addReg(MI.getOperand(ScratchIdx).getReg()));
>>>> -
>>>> +  unsigned EncodedBytes = 0;
>>>> +  int64_t CallTarget = MI.getOperand(StartIdx + 2).getImm();
>>>> +  if (CallTarget) {
>>>> +    // Emit MOV to materialize the target address and the CALL to target.
>>>> +    // This is encoded with 12-13 bytes, depending on which register is used.
>>>> +    // We conservatively assume that it is 12 bytes and emit in worst case one
>>>> +    // extra NOP byte.
>>>> +    EncodedBytes = 12;
>>>> +    OutStreamer.EmitInstruction(MCInstBuilder(X86::MOV64ri)
>>>> +                                .addReg(MI.getOperand(ScratchIdx).getReg())
>>>> +                                .addImm(CallTarget));
>>>> +    OutStreamer.EmitInstruction(MCInstBuilder(X86::CALL64r)
>>>> +                                .addReg(MI.getOperand(ScratchIdx).getReg()));
>>>> +  }
>>>>  // Emit padding.
>>>>  unsigned NumNOPBytes = MI.getOperand(StartIdx + 1).getImm();
>>>>  assert(NumNOPBytes >= EncodedBytes &&
>>>> 
>>>> Modified: llvm/trunk/test/CodeGen/X86/patchpoint.ll
>>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/patchpoint.ll?rev=194676&r1=194675&r2=194676&view=diff
>>>> ==============================================================================
>>>> --- llvm/trunk/test/CodeGen/X86/patchpoint.ll (original)
>>>> +++ llvm/trunk/test/CodeGen/X86/patchpoint.ll Thu Nov 14 00:54:10 2013
>>>> @@ -79,6 +79,22 @@ entry:
>>>>  ret i64 10
>>>> }
>>>> 
>>>> +; Test small patchpoints that don't emit calls.
>>>> +define void @small_patchpoint_codegen(i64 %p1, i64 %p2, i64 %p3, i64 %p4) {
>>>> +entry:
>>>> +; CHECK-LABEL: small_patchpoint_codegen:
>>>> +; CHECK:      Ltmp
>>>> +; CHECK:      nop
>>>> +; CHECK-NEXT: nop
>>>> +; CHECK-NEXT: nop
>>>> +; CHECK-NEXT: nop
>>>> +; CHECK-NEXT: nop
>>>> +; CHECK-NEXT: popq
>>>> +; CHECK-NEXT: ret
>>>> +  %result = tail call i64 (i32, i32, i8*, i32, ...)* @llvm.experimental.patchpoint.i64(i32 5, i32 5, i8* null, i32 2, i64 %p1, i64 %p2)
>>>> +  ret void
>>>> +}
>>>> +
>>>> declare void @llvm.experimental.stackmap(i32, i32, ...)
>>>> declare void @llvm.experimental.patchpoint.void(i32, i32, i8*, i32, ...)
>>>> declare i64 @llvm.experimental.patchpoint.i64(i32, i32, i8*, i32, ...)
>>>> 
>>>> 
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>>