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/*========================== begin_copyright_notice ============================
Copyright (C) 2023-2024 Intel Corporation
SPDX-License-Identifier: MIT
============================= end_copyright_notice ===========================*/
#include "LowerInvokeSIMD.hpp"
#include "Compiler/CodeGenPublic.h"
#include "Compiler/CISACodeGen/OpenCLKernelCodeGen.hpp"
#include "Compiler/IGCPassSupport.h"
#include "llvmWrapper/IR/DerivedTypes.h"
#include "common/LLVMWarningsPush.hpp"
#include <llvm/IR/Function.h>
#include <llvm/IR/Instructions.h>
#include <llvm/IR/Module.h>
#include "common/LLVMWarningsPop.hpp"
#include <unordered_set>
using namespace llvm;
using namespace IGC;
// Register pass to igc-opt
#define PASS_FLAG "igc-lower-invoke-simd"
#define PASS_DESCRIPTION "Lower calls to invoke_simd DPCPP builtins"
#define PASS_CFG_ONLY false
#define PASS_ANALYSIS false
IGC_INITIALIZE_PASS_BEGIN(LowerInvokeSIMD, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
IGC_INITIALIZE_PASS_DEPENDENCY(CodeGenContextWrapper)
IGC_INITIALIZE_PASS_DEPENDENCY(MetaDataUtilsWrapper)
IGC_INITIALIZE_PASS_END(LowerInvokeSIMD, PASS_FLAG, PASS_DESCRIPTION, PASS_CFG_ONLY, PASS_ANALYSIS)
char LowerInvokeSIMD::ID = 0;
namespace {
static const char *FNATTR_REFERENCED_INDIRECTLY = "referenced-indirectly";
static const char *FNATTR_INVOKE_SIMD_TARGET = "invoke_simd_target";
} // namespace
LowerInvokeSIMD::LowerInvokeSIMD() : ModulePass(ID) { initializeLowerInvokeSIMDPass(*PassRegistry::getPassRegistry()); }
// Searches for invoke_simd calls and replaces them with calls to
// function pointer, that is the first arg of the call.
void LowerInvokeSIMD::visitCallInst(CallInst &CI) {
Function *F = CI.getCalledFunction();
if (!F)
return;
if (!F->getName().contains("__builtin_invoke_simd"))
return;
auto Ctx = getAnalysis<CodeGenContextWrapper>().getCodeGenContext();
// invoke_simd is allowed only on compute path.
auto OCLCtx = static_cast<OpenCLProgramContext *>(Ctx);
bool forceBinaryLinking = false;
// First argument is a function pointer. We need to bitcast it to lowered
// type. The type will be deducted from this invocation.
SmallVector<Type *, 8> ArgTys;
SmallVector<Value *, 8> ArgVals;
// Skip first param, as it is the function pointer to call.
for (unsigned i = 1; i < F->getFunctionType()->getNumParams(); ++i) {
ArgTys.push_back(F->getFunctionType()->getParamType(i));
ArgVals.push_back(CI.getArgOperand(i));
}
auto FTy = FunctionType::get(F->getFunctionType()->getReturnType(), ArgTys, false);
m_Builder->SetInsertPoint(&CI);
CallInst *NewCall = nullptr;
std::error_code EC;
if (Function *Callee = dyn_cast<Function>(CI.getArgOperand(0))) {
if (!Callee->isDeclaration()) {
OCLCtx->EmitError("invoke_simd has SPMD function as invoke target."
"Only ESIMD functions can be invoked by this function.",
&CI);
return;
}
if (OCLCtx->m_DirectCallFunctions.count(Callee->getName().str()) == 0) {
OCLCtx->EmitWarning("It seems that definition is not provided for invoke_simd target. "
"Link-time optimizations will not be triggered.");
forceBinaryLinking = true;
}
Function *NewFunc = nullptr;
if (m_OldFuncToNewFuncMap.find(Callee) == m_OldFuncToNewFuncMap.end()) {
std::string oldName = std::string(Callee->getName());
Callee->setName(Callee->getName() + ".old");
NewFunc = Function::Create(FTy, Callee->getLinkage(), oldName, *Callee->getParent());
NewFunc->setAttributes(Callee->getAttributes());
// If we don't have the definition in .visaasm, revert to regular binary
// linking.
if (!forceBinaryLinking) {
NewFunc->addFnAttr(FNATTR_INVOKE_SIMD_TARGET);
if (NewFunc->hasFnAttribute(FNATTR_REFERENCED_INDIRECTLY)) {
NewFunc->removeFnAttr(FNATTR_REFERENCED_INDIRECTLY);
}
}
NewFunc->setCallingConv(Callee->getCallingConv());
m_OldFuncToNewFuncMap[Callee] = NewFunc;
} else {
NewFunc = m_OldFuncToNewFuncMap[Callee];
}
NewCall = m_Builder->CreateCall(NewFunc, ArgVals);
fixUniformParamsAndSIMDSize(Callee, *NewCall);
} else {
auto PTy = PointerType::get(FTy, cast<PointerType>(CI.getArgOperand(0)->getType())->getAddressSpace());
auto CastedPointer = m_Builder->CreateBitCast(CI.getArgOperand(0), PTy);
NewCall = m_Builder->CreateCall(FTy, CastedPointer, ArgVals);
}
NewCall->setCallingConv(CI.getCallingConv());
NewCall->setDebugLoc(CI.getDebugLoc());
CI.replaceAllUsesWith(NewCall);
CI.eraseFromParent();
m_changed = true;
}
// Compare arguments of the original ESIMD function with argument types deduced
// from invoke_simd builtin and used in the NewCall. If an argument is same in
// both, it is treated as scalar on ESIMD path.
void LowerInvokeSIMD::fixUniformParamsAndSIMDSize(const llvm::Function *ESIMDFunction, llvm::CallInst &NewCall) {
auto ESIMDFuncType = ESIMDFunction->getFunctionType();
auto SPMDFuncType = NewCall.getCalledFunction()->getFunctionType();
int ParamNumber = 0;
for (auto ESIMDParamType = ESIMDFuncType->param_begin(), SPMDParamType = SPMDFuncType->param_begin();
ESIMDParamType != ESIMDFuncType->param_end() && SPMDParamType != SPMDFuncType->param_end();
++ESIMDParamType, ++SPMDParamType, ++ParamNumber) {
if (*ESIMDParamType == *SPMDParamType) {
Value *args[3];
args[0] = NewCall.getArgOperand(ParamNumber);
args[1] = m_Builder->getInt32(0);
args[2] = m_Builder->getInt32(0);
// Get the first SIMD channel, as the spec says that all work items in the
// group must execute it.
Function *simdShuffleFunc = GenISAIntrinsic::getDeclaration(
NewCall.getModule(), GenISAIntrinsic::GenISA_WaveShuffleIndex, args[0]->getType());
m_Builder->SetInsertPoint(&NewCall);
auto ShuffleCall = m_Builder->CreateCall(simdShuffleFunc, args);
NewCall.setArgOperand(ParamNumber, ShuffleCall);
} else {
IGC_ASSERT((*ESIMDParamType)->isVectorTy());
int DeducedSIMDSize = (int)llvm::cast<IGCLLVM::FixedVectorType>(*ESIMDParamType)->getNumElements();
IGC_ASSERT(DeducedSIMDSize == 8 || DeducedSIMDSize == 16 || DeducedSIMDSize == 32);
auto MdUtils = getAnalysis<MetaDataUtilsWrapper>().getMetaDataUtils();
if (MdUtils->findFunctionsInfoItem(NewCall.getFunction()) == MdUtils->end_FunctionsInfo())
continue;
auto FuncInfoMD = MdUtils->getFunctionsInfoItem(NewCall.getFunction());
int CurrentSIMDSize = FuncInfoMD->getSubGroupSize()->getSIMDSize();
if (CurrentSIMDSize != 0 && CurrentSIMDSize != DeducedSIMDSize) {
auto Ctx = static_cast<OpenCLProgramContext *>(getAnalysis<CodeGenContextWrapper>().getCodeGenContext());
Ctx->EmitError("SIMD size does not match for invoke_simd calls!", &NewCall);
return;
}
FuncInfoMD->getSubGroupSize()->setSIMDSize(DeducedSIMDSize);
}
}
}
bool LowerInvokeSIMD::runOnModule(Module &M) {
IGCLLVM::IRBuilder<> builder(M.getContext());
m_Builder = &builder;
m_changed = false;
m_OldFuncToNewFuncMap.clear();
visit(M);
// If there are uses of vc functions outside invoke_simd calls (e.g. function
// pointer is taken), replace the old functions with new.
for (const auto &it : m_OldFuncToNewFuncMap) {
Function *OldFunc = it.first;
Function *NewFunc = it.second;
for (auto &use : OldFunc->uses()) {
if (!isa<Instruction>(use.getUser()))
continue;
Instruction *User = cast<Instruction>(use.getUser());
m_Builder->SetInsertPoint(cast<Instruction>(User));
auto CastedPointer = m_Builder->CreateBitCast(NewFunc, OldFunc->getType());
use.set(CastedPointer);
}
}
return m_changed;
}
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