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codegen_llvm.cc
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
/*!
* \file codegen_llvm.cc
*/
#ifdef TVM_LLVM_VERSION
// Part of the code are adapted from Halide's CodeGen_LLVM
#include "codegen_llvm.h"
#include <llvm/ADT/ArrayRef.h>
#include <llvm/ADT/SmallVector.h>
#include <llvm/ADT/StringRef.h>
#if LLVM_VERSION_MAJOR >= 17
#include <llvm/TargetParser/Triple.h>
#else
#include <llvm/ADT/Triple.h>
#endif
#include <llvm/Analysis/TargetTransformInfo.h>
#if TVM_LLVM_VERSION >= 50
#include <llvm/BinaryFormat/Dwarf.h>
#else
#include <llvm/Support/Dwarf.h>
#endif
#if TVM_LLVM_VERSION >= 60
#include <llvm/CodeGen/TargetSubtargetInfo.h>
#else
#include <llvm/Target/TargetSubtargetInfo.h>
#endif
#include <llvm/IR/Argument.h>
#include <llvm/IR/Attributes.h>
#include <llvm/IR/BasicBlock.h>
#include <llvm/IR/CallingConv.h>
#include <llvm/IR/Constants.h>
#include <llvm/IR/DIBuilder.h>
#include <llvm/IR/DataLayout.h>
#include <llvm/IR/DebugInfoMetadata.h>
#include <llvm/IR/DerivedTypes.h>
#if TVM_LLVM_VERSION >= 150
#include <llvm/IR/FMF.h>
#else
#include <llvm/IR/Operator.h>
#endif
#include <llvm/IR/Function.h>
#include <llvm/IR/GlobalVariable.h>
#include <llvm/IR/Instructions.h>
#include <llvm/IR/Intrinsics.h>
#include <llvm/IR/LLVMContext.h>
#include <llvm/IR/MDBuilder.h>
#include <llvm/IR/Metadata.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Type.h>
#include <llvm/IR/Verifier.h>
#include <llvm/IRReader/IRReader.h>
#include <llvm/Linker/Linker.h>
#include <llvm/Pass.h>
#if TVM_LLVM_VERSION >= 160
#include <llvm/IR/Verifier.h> // For VerifierPass
#include <llvm/Passes/PassBuilder.h>
#include <llvm/Passes/StandardInstrumentations.h>
#include <llvm/TargetParser/Host.h>
#else
#include <llvm/IR/LegacyPassManager.h>
#include <llvm/Support/Host.h>
#include <llvm/Transforms/IPO/PassManagerBuilder.h>
#endif
#if TVM_LLVM_VERSION >= 100
#include <llvm/Support/Alignment.h>
#include <llvm/Support/TypeSize.h>
#endif
#include <llvm/Support/CodeGen.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/Support/SourceMgr.h>
#include <llvm/Target/TargetMachine.h>
#include <llvm/Transforms/IPO.h>
#include <llvm/Transforms/Utils/ModuleUtils.h>
#include <tvm/runtime/c_runtime_api.h>
#include <tvm/runtime/device_api.h>
#include <tvm/tir/op.h>
#include <algorithm>
#include <functional>
#include <memory>
#include <sstream>
#include <string>
#include <utility>
#include <vector>
#include "../../arith/pattern_match.h"
#include "../build_common.h"
#include "../func_registry_generator.h"
#include "codegen_params.h"
#include "llvm_instance.h"
namespace tvm {
namespace codegen {
// CodeGenLLVM has members of type std::unique_ptr<T>. These members will be
// instantiated in the constructor, which will requre that the type T is
// complete at that point. Put the constructor (and destructor) here, since
// all types should be complete here.
CodeGenLLVM::CodeGenLLVM() = default;
CodeGenLLVM::~CodeGenLLVM() = default;
CodeGenLLVM::DebugInfo::~DebugInfo() = default;
std::unique_ptr<CodeGenLLVM> CodeGenLLVM::Create(LLVMTarget* llvm_target) {
std::string target = llvm_target->GetOrCreateTargetMachine()->getTarget().getName();
std::string factory_template = "tvm.codegen.llvm.target_";
void* handle = nullptr;
if (const PackedFunc* f = runtime::Registry::Get(factory_template + target)) {
handle = (*f)();
} else if (const PackedFunc* f = runtime::Registry::Get(factory_template + "cpu")) {
handle = (*f)();
} else {
LOG(FATAL) << "no factory function for codegen for target " << target;
}
if (handle) {
return std::unique_ptr<CodeGenLLVM>(static_cast<CodeGenLLVM*>(handle));
} else {
LOG(FATAL) << "unable to create codegen for target " << target;
}
}
void CodeGenLLVM::Init(const std::string& module_name, LLVMTarget* llvm_target,
Optional<String> system_lib_prefix, bool dynamic_lookup,
bool target_c_runtime) {
llvm_target_ = llvm_target;
llvm::LLVMContext* ctx = llvm_target_->GetContext();
builder_.reset(new IRBuilder(*ctx));
module_.reset(new llvm::Module(module_name, *ctx));
md_builder_.reset(new llvm::MDBuilder(*ctx));
// types
t_void_ = llvm::Type::getVoidTy(*ctx);
t_void_p_ = llvmGetPointerTo(llvm::Type::getInt8Ty(*ctx), GetGlobalAddressSpace());
t_int_ = llvm::Type::getInt32Ty(*ctx);
t_char_ = llvm::Type::getInt8Ty(*ctx);
t_int8_ = llvm::Type::getInt8Ty(*ctx);
t_int16_ = llvm::Type::getInt16Ty(*ctx);
t_int32_ = llvm::Type::getInt32Ty(*ctx);
t_int64_ = llvm::Type::getInt64Ty(*ctx);
t_float64_ = llvm::Type::getDoubleTy(*ctx);
// meta data
md_very_likely_branch_ = md_builder_->createBranchWeights(1 << 20, 1);
md_tbaa_root_ = md_builder_->createTBAARoot("tvm-tbaa");
md_tbaa_alias_set_ = md_builder_->createTBAANode("tvm-alias", md_tbaa_root_);
InitTarget();
}
void CodeGenLLVM::SetFastMathFlags(llvm::FastMathFlags fmf) { builder_->setFastMathFlags(fmf); }
void CodeGenLLVM::InitTarget() {
llvm::TargetMachine* tm = llvm_target_->GetOrCreateTargetMachine();
module_->setTargetTriple(tm->getTargetTriple().str());
module_->setDataLayout(tm->createDataLayout());
#if TVM_LLVM_VERSION >= 200
data_layout_.reset(new llvm::DataLayout(module_.get()->getDataLayout()));
#else
data_layout_.reset(new llvm::DataLayout(module_.get()));
#endif
if (native_vector_bits_ == 0) {
const auto& arch = tm->getTargetTriple().getArch();
if (arch == llvm::Triple::x86_64) {
// for avx512
native_vector_bits_ = 512;
} else if (arch == llvm::Triple::x86) {
native_vector_bits_ = 256;
} else if (arch == llvm::Triple::arm || arch == llvm::Triple::aarch64) {
native_vector_bits_ = 128;
} else {
native_vector_bits_ = 128;
std::string arch_name = std::string(tm->getTargetTriple().getArchName());
LOG(WARNING) << "Set native vector bits to be 128 for " << arch_name;
}
}
#if TVM_LLVM_VERSION >= 60
bool use_float16_abi = false;
#if TVM_LLVM_VERSION >= 150
// For conversions between _Float16 and float, LLVM uses runtime functions
// __extendhfsf2 and __truncsfhf2. On X86 up until version 14, LLVM used
// "uint16_t" for representing _Float16. Starting with LLVM 15, half-precision
// values can be passed in XMM registers (i.e. as floating-point). This happens
// when the compilation target has SSE2 enabled (either directly, or by enabling
// a feature that implies SSE2).
// Because the names of the conversion functions remain unchanged, it is impossible
// for TVM to provide them in the runtime, and have them work in both cases.
// To alleviate this issue, emit these functions directly into the target module
// after detecting whether or not to use floating-point ABI. To allow the linker
// to remove potential duplicates (or if they are unused), they are weak and
// reside in a separate section (ELF).
llvm::Triple::ArchType arch_type = tm->getTargetTriple().getArch();
if (arch_type == llvm::Triple::x86 || arch_type == llvm::Triple::x86_64) {
// Detect if SSE2 is enabled. This determines whether float16 ABI is used.
std::stringstream os;
const char fname[] = "test_sse2";
os << "target triple = \"" << llvm_target_->GetTargetTriple() << "\"\n"
<< "define void @" << fname << "() #0 { ret void } attributes #0 = { \"target-cpu\"=\""
<< llvm_target_->GetCPU() << "\" ";
if (auto&& fs = llvm_target_->GetTargetFeatureString(); !fs.empty()) {
os << "\"target-features\"=\"" << fs << "\" ";
}
os << "}\n";
auto mod = llvm_target_->GetInstance().ParseIR(os.str());
auto* test_sse2 = mod->getFunction(fname);
ICHECK(test_sse2 != nullptr) << "Module creation error";
use_float16_abi = tm->getSubtargetImpl(*test_sse2)->checkFeatures("+sse2");
}
#endif // TVM_LLVM_VERSION >= 150
// Call this function only with LLVM >= 6.0. The code it emits uses "dso_local"
// which was introduced in LLVM 6.
EmitFloat16ConversionBuiltins(use_float16_abi);
#endif // TVM_LLVM_VERSION >= 60
}
llvm::Function* CodeGenLLVM::DeclareFunction(const GlobalVar& gvar, const PrimFunc& f) {
return this->DeclareFunctionInternal(gvar, f);
}
void CodeGenLLVM::AddFunction(const GlobalVar& gvar, const PrimFunc& f) {
this->AddFunctionInternal(gvar, f);
}
void CodeGenLLVM::InitFuncState() {
var_map_.clear();
alias_var_set_.clear();
alloc_storage_info_.clear();
volatile_buf_.clear();
analyzer_.reset(new arith::Analyzer());
}
std::tuple<std::string, llvm::Function::LinkageTypes> CodeGenLLVM::GetLinkage(
const GlobalVar& gvar, const PrimFunc& func) {
if (auto global_symbol = func->GetAttr<String>(tvm::attr::kGlobalSymbol)) {
return {global_symbol.value(), llvm::Function::ExternalLinkage};
}
std::string symbol_name = [&]() {
std::stringstream ss;
ss << "_internal_";
ss << gvar->name_hint;
return ss.str();
}();
return {symbol_name, llvm::Function::PrivateLinkage};
}
llvm::Function* CodeGenLLVM::DeclareFunctionInternal(const GlobalVar& gvar, const PrimFunc& func) {
if (auto it = functions_.find(gvar.get()); it != functions_.end()) {
return it->second;
}
ICHECK_EQ(func->buffer_map.size(), 0U)
<< "Cannot codegen function with buffer_map, please lower them first";
std::vector<llvm::Type*> param_types;
is_restricted_ = func->HasNonzeroAttr(tir::attr::kNoAlias);
for (Var param : func->params) {
param_types.push_back(GetLLVMType(param));
if (!is_restricted_ && param.dtype().is_handle()) {
alias_var_set_.insert(param.get());
}
}
llvm::FunctionType* ftype =
llvm::FunctionType::get(GetLLVMType(func->ret_type), param_types, false);
auto [symbol_name, linkage_type] = GetLinkage(gvar, func);
auto function = module_->getFunction(MakeStringRef(symbol_name));
if (function == nullptr) {
function =
llvm::Function::Create(ftype, linkage_type, MakeStringRef(symbol_name), module_.get());
}
function->setCallingConv(llvm::CallingConv::C);
function->setDLLStorageClass(llvm::GlobalValue::DLLStorageClassTypes::DLLExportStorageClass);
SetTargetAttributes(function);
functions_[gvar.get()] = function;
return function;
}
void CodeGenLLVM::AddFunctionInternal(const GlobalVar& gvar, const PrimFunc& f) {
this->InitFuncState();
function_ = DeclareFunctionInternal(gvar, f);
// set var map and align information
auto arg_it = function_->arg_begin();
for (size_t i = 0; i < f->params.size(); ++i, ++arg_it) {
llvm::Argument* v = &(*arg_it);
const Var& var = f->params[i];
var_map_[var.get()] = v;
v->setName(std::string(var->name_hint));
if (is_restricted_) {
if (var.dtype().is_handle() && !alias_var_set_.count(var.get())) {
// set non alias.
#if TVM_LLVM_VERSION >= 50
function_->addParamAttr(i, llvm::Attribute::NoAlias);
#else
function_->setDoesNotAlias(i + 1);
#endif
}
}
}
llvm::LLVMContext* ctx = llvm_target_->GetContext();
llvm::BasicBlock* entry = llvm::BasicBlock::Create(*ctx, "entry", function_);
builder_->SetInsertPoint(entry);
this->VisitStmt(f->body);
// Add alignment attribute if needed.
#if TVM_LLVM_VERSION >= 50
for (size_t i = 0; i < f->params.size(); ++i) {
const Var& var = f->params[i];
auto f = alloc_storage_info_.find(var.get());
if (f != alloc_storage_info_.end()) {
unsigned align = f->second.alignment;
if (align > 1) {
auto attr = llvm::Attribute::get(*ctx, llvm::Attribute::Alignment, align);
function_->addParamAttr(i, attr);
}
}
}
#endif
EmitDebugLocation(f->span);
if (IsVoidType(f->ret_type)) {
// All other return types are handled when encountering
// builtin::ret().
builder_->CreateRetVoid();
} else {
builder_->CreateRet(ConstInt32(0));
}
}
void CodeGenLLVM::Verify() const {
std::string verify_errors_storage;
llvm::raw_string_ostream verify_errors(verify_errors_storage);
LOG_IF(FATAL, llvm::verifyModule(*module_, &verify_errors))
<< "LLVM module verification failed with the following errors: \n"
<< verify_errors.str();
}
std::unique_ptr<llvm::Module> CodeGenLLVM::Finish() {
this->AddStartupFunction();
for (size_t i = 0; i < link_modules_.size(); ++i) {
ICHECK(!llvm::Linker::linkModules(*module_, std::move(link_modules_[i])))
<< "Failed to link modules";
}
link_modules_.clear();
this->Verify();
this->Optimize();
this->Verify();
return std::move(module_);
}
void CodeGenLLVM::HandleImport(const std::string& code) {
llvm::StringRef code_str(code);
std::unique_ptr<llvm::Module> mlib;
#if TVM_LLVM_VERSION >= 180
if (code_str.ends_with(".ll") || code_str.ends_with(".bc")) {
#else
if (code_str.endswith(".ll") || code_str.endswith(".bc")) {
#endif
mlib = llvm_target_->GetInstance().LoadIR(code);
} else {
mlib = llvm_target_->GetInstance().ParseIR(code);
}
mlib->setTargetTriple(llvm_target_->GetTargetTriple());
mlib->setDataLayout(llvm_target_->GetOrCreateTargetMachine()->createDataLayout());
// mark all the functions as force inline
for (llvm::Function& f : mlib->functions()) {
f.removeFnAttr(llvm::Attribute::OptimizeNone);
f.removeFnAttr(llvm::Attribute::NoInline);
f.addFnAttr(llvm::Attribute::AlwaysInline);
f.setLinkage(llvm::GlobalValue::AvailableExternallyLinkage);
}
// add to linker libraries.
this->AddLinkModule(std::move(mlib));
}
void CodeGenLLVM::AddLinkModule(std::unique_ptr<llvm::Module>&& mod) {
link_modules_.emplace_back(std::move(mod));
}
void CodeGenLLVM::AddMainFunction(const std::string& entry_func_name) {
LOG(FATAL) << "not implemented";
}
llvm::Value* CodeGenLLVM::GetThreadIndex(const IterVar& iv) { LOG(FATAL) << "not implemented"; }
llvm::Value* CodeGenLLVM::CreateStorageSync(const CallNode* op) { LOG(FATAL) << "not implemented"; }
#if TVM_LLVM_VERSION >= 160
// Use new pass manager
void CodeGenLLVM::Optimize() {
llvm::TargetMachine* tm = llvm_target_->GetOrCreateTargetMachine();
bool debug_logging = false;
bool verify_each = false;
llvm::PipelineTuningOptions pto = llvm::PipelineTuningOptions();
llvm::PassInstrumentationCallbacks pic;
llvm::PassBuilder builder(tm, pto, std::nullopt, &pic);
llvm::LoopAnalysisManager lam;
llvm::FunctionAnalysisManager fam;
llvm::CGSCCAnalysisManager cgam;
llvm::ModuleAnalysisManager mam;
builder.registerLoopAnalyses(lam);
builder.registerFunctionAnalyses(fam);
builder.registerCGSCCAnalyses(cgam);
builder.registerModuleAnalyses(mam);
builder.crossRegisterProxies(lam, fam, cgam, mam);
// Construct the default pass pipeline depending on the opt level.
std::string pipeline;
#if TVM_LLVM_VERSION <= 170
switch (llvm_target_->GetOptLevel()) {
case llvm::CodeGenOpt::Level::None:
pipeline = "default<O0>";
break;
case llvm::CodeGenOpt::Level::Less:
pipeline = "default<O1>";
break;
case llvm::CodeGenOpt::Level::Default:
pipeline = "default<O2>";
break;
default:
// CodeGenOpt::Level::Aggressive
pipeline = "default<O3>";
break;
}
#else
switch (llvm_target_->GetOptLevel()) {
case llvm::CodeGenOptLevel::None:
pipeline = "default<O0>";
break;
case llvm::CodeGenOptLevel::Less:
pipeline = "default<O1>";
break;
case llvm::CodeGenOptLevel::Default:
pipeline = "default<O2>";
break;
default:
// CodeGenOptLevel::Aggressive
pipeline = "default<O3>";
break;
}
#endif
llvm::StandardInstrumentations si(*llvm_target_->GetContext(), debug_logging, verify_each);
#if LLVM_VERSION_MAJOR >= 17
si.registerCallbacks(pic, &mam);
#else
si.registerCallbacks(pic, &fam);
#endif
llvm::ModulePassManager mpass;
if (verify_each) {
mpass.addPass(llvm::VerifierPass());
}
if (auto err = builder.parsePassPipeline(mpass, pipeline)) {
LOG(FATAL) << "error parsing pass pipeline '" << pipeline
<< "':" << llvm::toString(std::move(err)) << '\n';
}
mpass.run(*module_, mam);
}
#else // TVM_LLVM_VERSION
class FPassManager : public llvm::legacy::FunctionPassManager {
public:
explicit FPassManager(llvm::Module* m) : llvm::legacy::FunctionPassManager(m) {}
// override add to allow messaging
void add(llvm::Pass* p) final { llvm::legacy::FunctionPassManager::add(p); }
};
class MPassManager : public llvm::legacy::PassManager {
public:
// override add to allow messaging
void add(llvm::Pass* p) final { llvm::legacy::PassManager::add(p); }
};
void CodeGenLLVM::InitPassManagerBuilder(llvm::PassManagerBuilder* builder) {}
void CodeGenLLVM::Optimize() {
// pass manager
FPassManager fpass(module_.get());
MPassManager mpass;
llvm::TargetMachine* tm = llvm_target_->GetOrCreateTargetMachine();
mpass.add(llvm::createTargetTransformInfoWrapperPass(tm->getTargetIRAnalysis()));
fpass.add(llvm::createTargetTransformInfoWrapperPass(tm->getTargetIRAnalysis()));
// place optimization pass
llvm::PassManagerBuilder builder;
// Use the same opt-level as specified in TargetMachine for running passes
llvm::CodeGenOpt::Level opt_level = llvm_target_->GetOptLevel();
switch (opt_level) {
case llvm::CodeGenOpt::Level::None:
builder.OptLevel = 0;
break;
case llvm::CodeGenOpt::Level::Less:
builder.OptLevel = 1;
break;
case llvm::CodeGenOpt::Level::Default:
builder.OptLevel = 2;
break;
default:
// CodeGenOpt::Level::Aggressive
builder.OptLevel = 3;
}
#if TVM_LLVM_VERSION >= 50
builder.Inliner = llvm::createFunctionInliningPass(builder.OptLevel, 0, false);
#else
builder.Inliner = llvm::createFunctionInliningPass(builder.OptLevel, 0);
#endif
builder.LoopVectorize = true;
builder.SLPVectorize = true;
this->InitPassManagerBuilder(&builder);
#if TVM_LLVM_VERSION >= 50
tm->adjustPassManager(builder);
#endif
builder.populateFunctionPassManager(fpass);
builder.populateModulePassManager(mpass);
fpass.doInitialization();
for (auto it = module_->begin(); it != module_->end(); ++it) {
fpass.run(*it);
}
fpass.doFinalization();
mpass.run(*module_);
}
#endif // TVM_LLVM_VERSION
int CodeGenLLVM::NativeVectorBits(const runtime::StorageScope& storage_scope) const {
return native_vector_bits_;
}
unsigned CodeGenLLVM::GetGlobalAddressSpace() const { return 0; }
llvm::Type* CodeGenLLVM::DTypeToLLVMType(const DataType& dtype) const {
if (dtype.is_handle()) {
ICHECK_EQ(dtype.lanes(), 1);
return t_void_p_;
}
if (dtype.is_void()) {
return t_void_;
}
llvm::Type* etype = nullptr;
llvm::LLVMContext* ctx = llvm_target_->GetContext();
if (dtype.is_int() || dtype.is_uint()) {
etype = llvm::Type::getIntNTy(*ctx, dtype.bits());
} else if (dtype.is_float()) {
switch (dtype.bits()) {
case 16:
etype = llvm::Type::getHalfTy(*ctx);
break;
case 32:
etype = llvm::Type::getFloatTy(*ctx);
break;
case 64:
etype = llvm::Type::getDoubleTy(*ctx);
break;
default:
LOG(FATAL) << "do not support " << dtype;
}
} else if (dtype.code() == DataType::kE4M3Float || dtype.code() == DataType::kE5M2Float) {
etype = llvm::Type::getInt8Ty(*ctx);
}
if (!dtype.is_scalar()) {
#if TVM_LLVM_VERSION >= 110
if (dtype.is_scalable_vector()) {
return llvm::VectorType::get(etype, dtype.vscale_factor(), true);
} else {
return llvm::FixedVectorType::get(etype, dtype.lanes());
}
#else
ICHECK(!dtype.is_scalable_vector())
<< "Versions of LLVM < 11 do not support scalable vectors. Please upgrade to a later "
"version.";
return llvm::VectorType::get(etype, dtype.lanes());
#endif
} else {
return etype;
}
} // namespace codegen
llvm::Type* CodeGenLLVM::GetLLVMType(const Type& type) const {
if (auto* ptr = type.as<PrimTypeNode>()) {
return DTypeToLLVMType(ptr->dtype);
} else if (auto* ptr = type.as<PointerTypeNode>()) {
// LLVM IR doesn't allow void*, nor do we require custom datatypes
// to have LLVM equivalents, so we need to recognize these
// patterns explicitly.
if (auto* primtype = ptr->element_type.as<PrimTypeNode>()) {
if (primtype->dtype.is_void() || primtype->dtype.code() >= DataType::kCustomBegin) {
return t_void_p_;
}
}
// TODO(tvm-team) consider put storage scope into the pointer type.
return llvmGetPointerTo(GetLLVMType(ptr->element_type), GetGlobalAddressSpace());
} else if (IsVoidType(type)) {
return t_void_;
} else {
LOG(FATAL) << "Type " << type << " does not have a corresponding LLVM Type";
}
}
llvm::Type* CodeGenLLVM::GetLLVMType(const PrimExpr& expr) const {
return GetLLVMType(GetType(expr));
}
// Add tbaa alias information for load
//
// use a binary tree typed system to declare information
// and allow alias to be distinguished across nodes.
//
// This trick comes from Halide's CodeGen_LLVM
//
void CodeGenLLVM::AddAliasInfo(llvm::Instruction* inst, const VarNode* buffer_var, PrimExpr index,
DataType access_dtype) {
if (alias_var_set_.count(buffer_var) != 0) {
// Mark all possibly aliased pointer as same type.
llvm::MDNode* meta = md_tbaa_alias_set_;
inst->setMetadata("tbaa", md_builder_->createTBAAStructTagNode(meta, meta, 0));
return;
}
int64_t base = 0, width = 0;
arith::PVar<IntImm> pbase, pstride;
arith::PVar<IntImm> planes;
// create meta-data for alias analysis
// Use a group of binary tree ranges of memory banks.
int64_t xwith = 0;
if (arith::ramp(pbase, pstride, planes).Match(index)) {
base = pbase.Eval()->value;
xwith = planes.Eval()->value * pstride.Eval()->value;
} else if (auto* ptr = index.as<tir::IntImmNode>()) {
base = ptr->value;
xwith = 1;
}
// adjust address index unit to byte
const int64_t unit_bit_width = 8;
const int64_t access_elem_bits = access_dtype.bits() * access_dtype.lanes();
base = base * access_elem_bits / unit_bit_width;
xwith = (xwith * access_elem_bits + unit_bit_width - 1) / unit_bit_width;
if (xwith > 0) {
width = 1;
while (width < xwith) {
width *= 2;
}
while (base % width) {
base -= base % width;
width *= 2;
}
}
llvm::MDNode* meta = md_tbaa_root_;
std::ostringstream buffer_addr;
buffer_addr << buffer_var;
meta = md_builder_->createTBAAScalarTypeNode(buffer_addr.str(), meta);
// create a tree-shape access structure.
if (width != 0) {
for (int64_t w = 1024; w >= width; w /= 2) {
int64_t b = (base / w) * w;
std::stringstream os;
os << buffer_var << ".w" << w << ".b" << b;
meta = md_builder_->createTBAAScalarTypeNode(os.str(), meta);
}
}
inst->setMetadata("tbaa", md_builder_->createTBAAStructTagNode(meta, meta, 0));
}
void CodeGenLLVM::GetAlignment(DataType t, const VarNode* buf_var, const PrimExpr& index,
int* p_alignment, int* p_native_bits) {
int max_align_bits = t.bits();
auto it = alloc_storage_info_.find(buf_var);
if (it != alloc_storage_info_.end()) {
const StorageInfo& info = it->second;
*p_native_bits =
NativeVectorBits(runtime::StorageScope::Create(GetPtrStorageScope(GetRef<Var>(buf_var))));
max_align_bits = info.alignment * 8;
} else {
*p_native_bits = native_vector_bits_;
}
arith::ModularSet me = analyzer_->modular_set(index);
int64_t base = me->base;
int64_t coeff = me->coeff;
int align_bits = t.bits();
while (align_bits < max_align_bits && base % 2 == 0 && coeff % 2 == 0) {
base = base / 2;
coeff = coeff / 2;
align_bits *= 2;
}
if (align_bits < 8) {
align_bits = 8;
}
*p_alignment = align_bits / 8;
}
llvm::GlobalVariable* CodeGenLLVM::AllocateSharedMemory(DataType dtype, size_t size,
unsigned int shared_address_space,
int alignment,
llvm::GlobalValue::LinkageTypes linkage) {
llvm::Type* type = llvm::ArrayType::get(DTypeToLLVMType(dtype), size);
llvm::GlobalVariable* global =
new llvm::GlobalVariable(*module_, type, false, linkage, llvm::UndefValue::get(type), "shmem",
nullptr, llvm::GlobalValue::NotThreadLocal, shared_address_space);
#if TVM_LLVM_VERSION >= 100
global->setAlignment(llvm::Align(alignment));
#else
global->setAlignment(alignment);
#endif
return global;
}
std::unique_ptr<CodeGenLLVM::DebugInfo> CodeGenLLVM::CreateDebugInfo(llvm::Module* module) {
#if TVM_LLVM_VERSION >= 100
auto debug_info = std::make_unique<CodeGenLLVM::DebugInfo>();
debug_info->di_builder_ = std::make_unique<llvm::DIBuilder>(*module);
#else
auto debug_info = llvm::make_unique<CodeGenLLVM::DebugInfo>();
debug_info->di_builder_ = llvm::make_unique<llvm::DIBuilder>(*module);
#endif
// TODO(tulloch): pass this information through relay::Span classes to the IRModule instance?
debug_info->file_ = debug_info->di_builder_->createFile("IRModule.CodeGenLLVM", ".");
const int runtime_version = 0;
const bool is_optimized = false;
const char* compiler_flags = "";
debug_info->compilation_unit_ = debug_info->di_builder_->createCompileUnit(
/*Lang=*/llvm::dwarf::DW_LANG_C, /*File=*/debug_info->file_, /*Producer=*/"TVM", is_optimized,
compiler_flags, runtime_version);
return debug_info;
}
llvm::Value* CodeGenLLVM::CreateVecSlice(llvm::Value* vec, int begin, int extent) {
int num_elems = GetVectorNumElements(vec);
if (extent == num_elems && begin == 0) return vec;
ICHECK(begin >= 0 && extent <= num_elems) << "Slicing out of bound!\n";
std::vector<llvm::Constant*> indices;
indices.reserve(extent);
for (int i = 0; i < extent; ++i) {
if (begin + i >= 0 && begin + i < num_elems) {
indices.push_back(llvm::ConstantInt::get(t_int32_, begin + i));
} else {
indices.push_back(llvm::UndefValue::get(t_int32_));
}
}
return builder_->CreateShuffleVector(vec, vec, llvm::ConstantVector::get(indices));
}
llvm::Value* CodeGenLLVM::CreateVecFlip(llvm::Value* vec) {
int num_elems = GetVectorNumElements(vec);
#if TVM_LLVM_VERSION >= 110
std::vector<int> indices;
#else
std::vector<unsigned> indices;
#endif
for (int i = 0; i < num_elems; ++i) {
indices.push_back(num_elems - i - 1);
}
return builder_->CreateShuffleVector(vec, vec, indices);
}
llvm::Value* CodeGenLLVM::CreateVecPad(llvm::Value* vec, int target_lanes) {
llvm::Value* mask = llvm::UndefValue::get(DTypeToLLVMType(DataType::Int(32, target_lanes)));
int num_elems = GetVectorNumElements(vec);
if (num_elems == target_lanes) return vec;
ICHECK_LT(num_elems, target_lanes);
for (int i = 0; i < num_elems; ++i) {
mask = builder_->CreateInsertElement(mask, ConstInt32(i), ConstInt32(i));
}
return builder_->CreateShuffleVector(vec, vec, mask);
}
llvm::Value* CodeGenLLVM::CreateVecConcat(std::vector<llvm::Value*> vecs) {
// To allow creating vectors from scalars, convert any scalars in "vecs" to single-lane
// LLVM vector types.
for (size_t i = 0, e = vecs.size(); i != e; ++i) {
llvm::Value* v = vecs[i];
if (!v->getType()->isVectorTy()) {
#if TVM_LLVM_VERSION >= 110
llvm::Type* vec_ty = llvm::FixedVectorType::get(v->getType(), 1);
#else
llvm::Type* vec_ty = llvm::VectorType::get(v->getType(), 1);
#endif
vecs[i] = builder_->CreateInsertElement(llvm::UndefValue::get(vec_ty), v, ConstInt32(0));
}
}
// concat vector, tree shape reduction
int total_lanes = 0;
for (llvm::Value* v : vecs) {
total_lanes += GetVectorNumElements(v);
}
while (vecs.size() > 1) {
std::vector<llvm::Value*> new_vecs;
for (size_t i = 0; i < vecs.size() - 1; i += 2) {
llvm::Value* lhs = vecs[i];
llvm::Value* rhs = vecs[i + 1];
const size_t lhs_lanes = GetVectorNumElements(lhs);
const size_t rhs_lanes = GetVectorNumElements(rhs);
if (lhs_lanes < rhs_lanes) {
lhs = CreateVecPad(lhs, rhs_lanes);
} else if (rhs_lanes < lhs_lanes) {
rhs = CreateVecPad(rhs, lhs_lanes);
}
const size_t shared_lanes = std::max(lhs_lanes, rhs_lanes);
#if TVM_LLVM_VERSION >= 110
std::vector<int> mask;
#else
std::vector<unsigned> mask;
#endif
for (size_t i = 0; i < lhs_lanes; ++i) {
mask.push_back(i);
}
for (size_t i = 0; i < rhs_lanes; ++i) {
mask.push_back(shared_lanes + i);
}
new_vecs.push_back(builder_->CreateShuffleVector(lhs, rhs, mask));
}
if (vecs.size() % 2 != 0) {
new_vecs.push_back(vecs.back());
}
vecs.swap(new_vecs);
}
return CreateVecSlice(vecs[0], 0, total_lanes);
}
void CodeGenLLVM::CreateSerialFor(llvm::Value* begin, llvm::Value* end, llvm::Value* stride,
const Var& loop_var, const Stmt& body) {
llvm::BasicBlock* pre_block = builder_->GetInsertBlock();
std::string loop_var_name = loop_var->name_hint;
llvm::LLVMContext* ctx = llvm_target_->GetContext();
auto* for_begin = llvm::BasicBlock::Create(*ctx, "for_begin_" + loop_var_name, function_);
auto* for_body = llvm::BasicBlock::Create(*ctx, "for_body_" + loop_var_name, function_);
auto* for_end = llvm::BasicBlock::Create(*ctx, "for_end_" + loop_var_name, function_);
builder_->CreateBr(for_begin);
builder_->SetInsertPoint(for_begin);
llvm::PHINode* loop_value = builder_->CreatePHI(begin->getType(), 2);
AddDebugInformation(loop_value, loop_var);
loop_value->addIncoming(begin, pre_block);
ICHECK(!var_map_.count(loop_var.get()));
var_map_[loop_var.get()] = loop_value;
auto lt = CreateLT(loop_var.dtype(), loop_value, end);
builder_->CreateCondBr(lt, for_body, for_end, md_very_likely_branch_);
builder_->SetInsertPoint(for_body);
EmitDebugLocation(body->span);
this->VisitStmt(body);
var_map_.erase(loop_var.get());
llvm::Value* loop_next = CreateAdd(loop_var.dtype(), loop_value, stride);
loop_value->addIncoming(loop_next, builder_->GetInsertBlock());
builder_->CreateBr(for_begin);
builder_->SetInsertPoint(for_end);
}
// cast operatpr
llvm::Value* CodeGenLLVM::CreateCast(DataType from, DataType to, llvm::Value* value) {
llvm::Type* target = DTypeToLLVMType(to);
if (value->getType() == target) return value;
// TODO(tvm-team): consider add native support
ICHECK(!from.is_bfloat16()) << "BF16 needs to be storaged lowered first";
ICHECK(!to.is_bfloat16()) << "BF16 needs to be storaged lowered first";
if (to.is_handle()) {
return builder_->CreateBitCast(value, target);
} else if (to.is_uint() && to.bits() == 1) {
if (from.is_float()) {
llvm::Constant* zero = llvm::ConstantFP::get(DTypeToLLVMType(from), 0.);
return builder_->CreateFCmpONE(value, zero);
} else {
llvm::Constant* zero = llvm::ConstantInt::get(DTypeToLLVMType(from), 0);
return builder_->CreateICmpNE(value, zero);
}
} else if (!from.is_float() && !to.is_float()) {
return builder_->CreateIntCast(value, target, from.is_int());
} else if (from.is_float() && to.is_int()) {
return builder_->CreateFPToSI(value, target);
} else if (from.is_float() && to.is_uint()) {
if (to.bits() < 8) {
value = builder_->CreateFPToUI(value, DTypeToLLVMType(to.with_bits(8)));
return builder_->CreateIntCast(value, target, false);
} else {
return builder_->CreateFPToUI(value, target);
}
} else if (from.is_int() && to.is_float()) {
return builder_->CreateSIToFP(value, target);
} else if (from.is_uint() && to.is_float()) {
return builder_->CreateUIToFP(value, target);
} else {
ICHECK(from.is_float() && to.is_float());
return builder_->CreateFPCast(value, target);
}
}
llvm::Constant* CodeGenLLVM::GetGlobalConstant(llvm::Constant* const_data, const std::string& name,
llvm::GlobalValue::LinkageTypes linkage_type) {
llvm::Type* ty = const_data->getType();
llvm::GlobalVariable* global =
new llvm::GlobalVariable(*module_, ty, true, linkage_type, const_data, name);
#if TVM_LLVM_VERSION >= 100
global->setAlignment(llvm::Align(1));
#else
global->setAlignment(1);
#endif
llvm::Constant* zero = ConstInt32(0);
llvm::Constant* indices[] = {zero, zero};
llvm::Constant* ptr = llvm::ConstantExpr::getGetElementPtr(ty, global, indices);
return ptr;
}
llvm::Constant* CodeGenLLVM::GetConstString(const std::string& str) {
if (auto it = str_map_.find(str); it != str_map_.end()) {
return it->second;
}
auto llvm_str = llvm::ConstantDataArray::getString(*llvm_target_->GetContext(), str);
auto ptr = GetGlobalConstant(llvm_str, ".str", llvm::GlobalValue::PrivateLinkage);
str_map_[str] = ptr;
return ptr;
}
CodeGenLLVM::TypedPointer CodeGenLLVM::CreateBufferPtr(llvm::Value* buffer_ptr,
DataType buffer_element_dtype,
llvm::ArrayRef<llvm::Value*> indices,
DataType value_dtype) {
ICHECK_EQ(indices.size(), 1) << "CodeGenLLVM requires all buffers to be flat 1-d buffers.";
llvm::Value* index = indices[0];
llvm::PointerType* buffer_ptr_type = llvm::dyn_cast<llvm::PointerType>(buffer_ptr->getType());
ICHECK(buffer_ptr_type != nullptr);
auto address_space = buffer_ptr_type->getAddressSpace();
llvm::Type* element_type = DTypeToLLVMType(buffer_element_dtype);
llvm::PointerType* element_ptr_type =
llvmGetPointerTo(DTypeToLLVMType(buffer_element_dtype), address_space);
llvm::Type* value_type = DTypeToLLVMType(value_dtype);
llvm::PointerType* value_ptr_type = llvmGetPointerTo(value_type, address_space);
ICHECK(index->getType()->isIntegerTy()) << "Expected buffer index to be an integer";
if (buffer_ptr_type != element_ptr_type) {
buffer_ptr = builder_->CreatePointerCast(buffer_ptr, element_ptr_type);
}
ICHECK(!HasAlignmentPadding(buffer_element_dtype))
<< "DType " << buffer_element_dtype
<< " has padding for alignment. TVM data arrays are expected to be densely packed, with no "
"padding for alignment.";
llvm::Value* value_ptr = builder_->CreateInBoundsGEP(element_type, buffer_ptr, index);
if (element_ptr_type != value_ptr_type) {
value_ptr = builder_->CreatePointerCast(value_ptr, value_ptr_type);
}
return TypedPointer(value_type, value_ptr);
}
llvm::Value* CodeGenLLVM::GetVarValue(const VarNode* v) const {
auto it = var_map_.find(v);
ICHECK(it != var_map_.end()) << "cannot find variable " << v->name_hint;
return it->second;
}