AMDGPU: Insert two S_NOP instructions for every high level source statement.

Patch by: Konstantin Zhuravlyov

Summary: Tools, such as debugger, need to pause execution based on user input (i.e. breakpoint). In order to do this, two S_NOP instructions are inserted for each high level source statement: one before first isa instruction of high level source statement, and one after last isa instruction of high level source statement. Further, debugger may replace S_NOP instructions with S_TRAP instructions based on user input.

Reviewers: tstellarAMD, arsenm

Subscribers: echristo, dblaikie, arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D17454

llvm-svn: 262579

1 files changed, 11 insertions, 0 deletions

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 32e9d8a9d19..df70b749d07 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -30,6 +30,7 @@
 #include "llvm/IR/Verifier.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/IR/LegacyPassManager.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/raw_os_ostream.h"
 #include "llvm/Transforms/IPO.h"
@@ -54,6 +55,7 @@ extern "C" void LLVMInitializeAMDGPUTarget() {
   initializeAMDGPUAnnotateUniformValuesPass(*PR);
   initializeAMDGPUPromoteAllocaPass(*PR);
   initializeSIAnnotateControlFlowPass(*PR);
+  initializeSIInsertNopsPass(*PR);
   initializeSIInsertWaitsPass(*PR);
   initializeSILowerControlFlowPass(*PR);
 }
@@ -145,6 +147,12 @@ GCNTargetMachine::GCNTargetMachine(const Target &T, const Triple &TT,
 //===----------------------------------------------------------------------===//
 
 namespace {
+
+cl::opt<bool> InsertNops(
+  "amdgpu-insert-nops",
+  cl::desc("Insert two nop instructions for each high level source statement"),
+  cl::init(false));
+
 class AMDGPUPassConfig : public TargetPassConfig {
 public:
   AMDGPUPassConfig(TargetMachine *TM, PassManagerBase &PM)
@@ -364,6 +372,9 @@ void GCNPassConfig::addPreSched2() {
 void GCNPassConfig::addPreEmitPass() {
   addPass(createSIInsertWaitsPass(), false);
   addPass(createSILowerControlFlowPass(), false);
+  if (InsertNops) {
+    addPass(createSIInsertNopsPass(), false);
+  }
 }
 
 TargetPassConfig *GCNTargetMachine::createPassConfig(PassManagerBase &PM) {