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

[Andrew Trick]

Public bots? I can’t find any.

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, ...)
>> 
>> 
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits