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ef0719f36b
Implement -femit-local-var-lifetime which adds local (stack) variable lifetime annotation to LLVM IR, which enables sharing stack space for variables whose lifetimes do not overlap. Resolves issue #2227 This is not enabled by default yet, to prevent miscompilation due to bugs (should be enabled in future for optimization levels > 0, and when sanitizers are enabled).
56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
//===-- gen/variable_lifetime.h - -------------------------------*- C++ -*-===//
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//
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// LDC – the LLVM D compiler
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//
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// This file is distributed under the BSD-style LDC license. See the LICENSE
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// file for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Codegen for local variable lifetime: llvm.lifetime.start abd
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// llvm.lifetime.end.
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//
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//===----------------------------------------------------------------------===//
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#pragma once
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#include <vector>
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#include <utility>
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namespace llvm {
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class Function;
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class Type;
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class Value;
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}
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struct IRState;
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struct LocalVariableLifetimeAnnotator {
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struct LocalVariableScope {
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std::vector<std::pair<llvm::Value *, llvm::Value *>> variables;
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};
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/// Stack of scopes, each scope can have multiple variables.
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std::vector<LocalVariableScope> scopes;
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/// Cache the llvm types and intrinsics used for codegen.
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llvm::Function *lifetimeStartFunction = nullptr;
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llvm::Function *lifetimeEndFunction = nullptr;
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llvm::Type *allocaType = nullptr;
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llvm::Function *getLLVMLifetimeStartFn();
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llvm::Function *getLLVMLifetimeEndFn();
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IRState &irs;
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public:
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LocalVariableLifetimeAnnotator(IRState &irs);
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/// Opens a new scope.
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void pushScope();
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/// Closes current scope and emits end-of-lifetime annotation for all
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/// variables in current scope.
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void popScope();
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/// Register a new local variable for lifetime annotation.
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void addLocalVariable(llvm::Value *address, llvm::Value *size);
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};
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