LLVM 17.0.0git
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1//===---------- speculation.cpp - Utilities for Speculation ----------===//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
10#include "llvm/IR/BasicBlock.h"
11#include "llvm/IR/Function.h"
12#include "llvm/IR/IRBuilder.h"
13#include "llvm/IR/Instruction.h"
15#include "llvm/IR/LLVMContext.h"
16#include "llvm/IR/Module.h"
17#include "llvm/IR/Type.h"
18#include "llvm/IR/Verifier.h"
20namespace llvm {
22namespace orc {
24// ImplSymbolMap methods
26 assert(SrcJD && "Tracking on Null Source .impl dylib");
27 std::lock_guard<std::mutex> Lockit(ConcurrentAccess);
28 for (auto &I : ImplMaps) {
29 auto It = Maps.insert({I.first, {I.second.Aliasee, SrcJD}});
30 // check rationale when independent dylibs have same symbol name?
31 assert(It.second && "ImplSymbols are already tracked for this Symbol?");
32 (void)(It);
33 }
36// Trigger Speculative Compiles.
37void Speculator::speculateForEntryPoint(Speculator *Ptr, uint64_t StubId) {
38 assert(Ptr && " Null Address Received in orc_speculate_for ");
39 Ptr->speculateFor(StubId);
43 MangleAndInterner &Mangle) {
46 JITEvaluatedSymbol SpeculateForEntryPtr(
47 pointerToJITTargetAddress(&speculateForEntryPoint),
49 return JD.define(absoluteSymbols({
50 {Mangle("__orc_speculator"), ThisPtr}, // Data Symbol
51 {Mangle("__orc_speculate_for"), SpeculateForEntryPtr} // Callable Symbol
52 }));
55// If two modules, share the same LLVMContext, different threads must
56// not access them concurrently without locking the associated LLVMContext
57// this implementation follows this contract.
58void IRSpeculationLayer::emit(std::unique_ptr<MaterializationResponsibility> R,
59 ThreadSafeModule TSM) {
61 assert(TSM && "Speculation Layer received Null Module ?");
62 assert(TSM.getContext().getContext() != nullptr &&
63 "Module with null LLVMContext?");
65 // Instrumentation of runtime calls, lock the Module
66 TSM.withModuleDo([this, &R](Module &M) {
67 auto &MContext = M.getContext();
68 auto SpeculatorVTy = StructType::create(MContext, "Class.Speculator");
69 auto RuntimeCallTy = FunctionType::get(
70 Type::getVoidTy(MContext),
71 {SpeculatorVTy->getPointerTo(), Type::getInt64Ty(MContext)}, false);
72 auto RuntimeCall =
74 "__orc_speculate_for", &M);
75 auto SpeclAddr = new GlobalVariable(
76 M, SpeculatorVTy, false, GlobalValue::LinkageTypes::ExternalLinkage,
77 nullptr, "__orc_speculator");
79 IRBuilder<> Mutator(MContext);
81 // QueryAnalysis allowed to transform the IR source, one such example is
82 // Simplify CFG helps the static branch prediction heuristics!
83 for (auto &Fn : M.getFunctionList()) {
84 if (!Fn.isDeclaration()) {
86 auto IRNames = QueryAnalysis(Fn);
87 // Instrument and register if Query has result
88 if (IRNames) {
90 // Emit globals for each function.
91 auto LoadValueTy = Type::getInt8Ty(MContext);
92 auto SpeculatorGuard = new GlobalVariable(
93 M, LoadValueTy, false, GlobalValue::LinkageTypes::InternalLinkage,
94 ConstantInt::get(LoadValueTy, 0),
95 "__orc_speculate.guard.for." + Fn.getName());
96 SpeculatorGuard->setAlignment(Align(1));
97 SpeculatorGuard->setUnnamedAddr(GlobalValue::UnnamedAddr::Local);
99 BasicBlock &ProgramEntry = Fn.getEntryBlock();
100 // Create BasicBlocks before the program's entry basicblock
101 BasicBlock *SpeculateBlock = BasicBlock::Create(
102 MContext, "__orc_speculate.block", &Fn, &ProgramEntry);
103 BasicBlock *SpeculateDecisionBlock = BasicBlock::Create(
104 MContext, "__orc_speculate.decision.block", &Fn, SpeculateBlock);
106 assert(SpeculateDecisionBlock == &Fn.getEntryBlock() &&
107 "SpeculateDecisionBlock not updated?");
108 Mutator.SetInsertPoint(SpeculateDecisionBlock);
110 auto LoadGuard =
111 Mutator.CreateLoad(LoadValueTy, SpeculatorGuard, "guard.value");
112 // if just loaded value equal to 0,return true.
113 auto CanSpeculate =
114 Mutator.CreateICmpEQ(LoadGuard, ConstantInt::get(LoadValueTy, 0),
115 "compare.to.speculate");
116 Mutator.CreateCondBr(CanSpeculate, SpeculateBlock, &ProgramEntry);
118 Mutator.SetInsertPoint(SpeculateBlock);
119 auto ImplAddrToUint =
120 Mutator.CreatePtrToInt(&Fn, Type::getInt64Ty(MContext));
121 Mutator.CreateCall(RuntimeCallTy, RuntimeCall,
122 {SpeclAddr, ImplAddrToUint});
123 Mutator.CreateStore(ConstantInt::get(LoadValueTy, 1),
124 SpeculatorGuard);
125 Mutator.CreateBr(&ProgramEntry);
127 assert(Mutator.GetInsertBlock()->getParent() == &Fn &&
128 "IR builder association mismatch?");
129 S.registerSymbols(internToJITSymbols(*IRNames),
130 &R->getTargetJITDylib());
131 }
132 }
133 }
134 });
136 assert(!TSM.withModuleDo([](const Module &M) { return verifyModule(M); }) &&
137 "Speculation Instrumentation breaks IR?");
139 NextLayer.emit(std::move(R), std::move(TSM));
142} // namespace orc
143} // namespace llvm
#define I(x, y, z)
Definition: MD5.cpp:58
Module.h This file contains the declarations for the Module class.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Basic Block Representation.
Definition: BasicBlock.h:56
static BasicBlock * Create(LLVMContext &Context, const Twine &Name="", Function *Parent=nullptr, BasicBlock *InsertBefore=nullptr)
Creates a new BasicBlock.
Definition: BasicBlock.h:105
const Function * getParent() const
Return the enclosing method, or null if none.
Definition: BasicBlock.h:112
static Constant * get(Type *Ty, uint64_t V, bool IsSigned=false)
If Ty is a vector type, return a Constant with a splat of the given value.
Definition: Constants.cpp:888
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:220
Lightweight error class with error context and mandatory checking.
Definition: Error.h:156
static FunctionType * get(Type *Result, ArrayRef< Type * > Params, bool isVarArg)
This static method is the primary way of constructing a FunctionType.
static Function * Create(FunctionType *Ty, LinkageTypes Linkage, unsigned AddrSpace, const Twine &N="", Module *M=nullptr)
Definition: Function.h:136
@ InternalLinkage
Rename collisions when linking (static functions).
Definition: GlobalValue.h:55
@ ExternalLinkage
Externally visible function.
Definition: GlobalValue.h:48
BasicBlock * GetInsertBlock() const
Definition: IRBuilder.h:174
Value * CreateICmpEQ(Value *LHS, Value *RHS, const Twine &Name="")
Definition: IRBuilder.h:2130
BranchInst * CreateCondBr(Value *Cond, BasicBlock *True, BasicBlock *False, MDNode *BranchWeights=nullptr, MDNode *Unpredictable=nullptr)
Create a conditional 'br Cond, TrueDest, FalseDest' instruction.
Definition: IRBuilder.h:1043
LoadInst * CreateLoad(Type *Ty, Value *Ptr, const char *Name)
Provided to resolve 'CreateLoad(Ty, Ptr, "...")' correctly, instead of converting the string to 'bool...
Definition: IRBuilder.h:1713
StoreInst * CreateStore(Value *Val, Value *Ptr, bool isVolatile=false)
Definition: IRBuilder.h:1726
Value * CreatePtrToInt(Value *V, Type *DestTy, const Twine &Name="")
Definition: IRBuilder.h:2006
BranchInst * CreateBr(BasicBlock *Dest)
Create an unconditional 'br label X' instruction.
Definition: IRBuilder.h:1037
void SetInsertPoint(BasicBlock *TheBB)
This specifies that created instructions should be appended to the end of the specified block.
Definition: IRBuilder.h:180
CallInst * CreateCall(FunctionType *FTy, Value *Callee, ArrayRef< Value * > Args=std::nullopt, const Twine &Name="", MDNode *FPMathTag=nullptr)
Definition: IRBuilder.h:2301
This provides a uniform API for creating instructions and inserting them into a basic block: either a...
Definition: IRBuilder.h:2558
Represents a symbol that has been evaluated to an address already.
Definition: JITSymbol.h:229
A Module instance is used to store all the information related to an LLVM module.
Definition: Module.h:65
static StructType * create(LLVMContext &Context, StringRef Name)
This creates an identified struct.
Definition: Type.cpp:533
PointerType * getPointerTo(unsigned AddrSpace=0) const
Return a pointer to the current type.
static Type * getVoidTy(LLVMContext &C)
static IntegerType * getInt8Ty(LLVMContext &C)
static IntegerType * getInt64Ty(LLVMContext &C)
StringRef getName() const
Return a constant reference to the value's name.
Definition: Value.cpp:308
virtual void emit(std::unique_ptr< MaterializationResponsibility > R, ThreadSafeModule TSM)=0
Emit should materialize the given IR.
void emit(std::unique_ptr< MaterializationResponsibility > R, ThreadSafeModule TSM) override
Emit should materialize the given IR.
Definition: Speculation.cpp:58
void trackImpls(SymbolAliasMap ImplMaps, JITDylib *SrcJD)
Definition: Speculation.cpp:25
Represents a JIT'd dynamic library.
Definition: Core.h:962
Error define(std::unique_ptr< MaterializationUnitType > &&MU, ResourceTrackerSP RT=nullptr)
Define all symbols provided by the materialization unit to be part of this JITDylib.
Definition: Core.h:1816
Mangles symbol names then uniques them in the context of an ExecutionSession.
Definition: Mangling.h:26
Error addSpeculationRuntime(JITDylib &JD, MangleAndInterner &Mangle)
Define symbols for this Speculator object (__orc_speculator) and the speculation runtime entry point ...
Definition: Speculation.cpp:42
void registerSymbols(FunctionCandidatesMap Candidates, JITDylib *JD)
Definition: Speculation.h:139
LLVMContext * getContext()
Returns a pointer to the LLVMContext that was used to construct this instance, or null if the instanc...
An LLVM Module together with a shared ThreadSafeContext.
ThreadSafeContext getContext() const
Returns the context for this ThreadSafeModule.
decltype(auto) withModuleDo(Func &&F)
Locks the associated ThreadSafeContext and calls the given function on the contained Module.
std::unique_ptr< AbsoluteSymbolsMaterializationUnit > absoluteSymbols(SymbolMap Symbols)
Create an AbsoluteSymbolsMaterializationUnit with the given symbols.
Definition: Core.h:771
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
JITTargetAddress pointerToJITTargetAddress(T *Ptr)
Convert a pointer to a JITTargetAddress.
Definition: JITSymbol.h:69
This struct is a compact representation of a valid (non-zero power of two) alignment.
Definition: Alignment.h:39