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//===--- Program.h - Bytecode for the constexpr VM --------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Defines a program which organises and links multiple bytecode functions.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_INTERP_PROGRAM_H
#define LLVM_CLANG_AST_INTERP_PROGRAM_H
#include <map>
#include <vector>
#include "Function.h"
#include "Pointer.h"
#include "PrimType.h"
#include "Record.h"
#include "Source.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
namespace clang {
class RecordDecl;
class Expr;
class FunctionDecl;
class StringLiteral;
class VarDecl;
namespace interp {
class Context;
class Record;
/// The program contains and links the bytecode for all functions.
class Program final {
public:
Program(Context &Ctx) : Ctx(Ctx) {}
~Program() {
// Manually destroy all the blocks. They are almost all harmless,
// but primitive arrays might have an InitMap* heap allocated and
// that needs to be freed.
for (Global *G : Globals)
G->block()->invokeDtor();
// Records might actually allocate memory themselves, but they
// are allocated using a BumpPtrAllocator. Call their desctructors
// here manually so they are properly freeing their resources.
for (auto RecordPair : Records) {
if (Record *R = RecordPair.second)
R->~Record();
}
}
/// Marshals a native pointer to an ID for embedding in bytecode.
unsigned getOrCreateNativePointer(const void *Ptr);
/// Returns the value of a marshalled native pointer.
const void *getNativePointer(unsigned Idx);
/// Emits a string literal among global data.
unsigned createGlobalString(const StringLiteral *S);
/// Returns a pointer to a global.
Pointer getPtrGlobal(unsigned Idx) const;
/// Returns the value of a global.
Block *getGlobal(unsigned Idx) {
assert(Idx < Globals.size());
return Globals[Idx]->block();
}
/// Finds a global's index.
std::optional<unsigned> getGlobal(const ValueDecl *VD);
/// Returns or creates a global an creates an index to it.
std::optional<unsigned> getOrCreateGlobal(const ValueDecl *VD,
const Expr *Init = nullptr);
/// Returns or creates a dummy value for unknown declarations.
std::optional<unsigned> getOrCreateDummy(const ValueDecl *VD);
/// Creates a global and returns its index.
std::optional<unsigned> createGlobal(const ValueDecl *VD, const Expr *Init);
/// Creates a global from a lifetime-extended temporary.
std::optional<unsigned> createGlobal(const Expr *E);
/// Creates a new function from a code range.
template <typename... Ts>
Function *createFunction(const FunctionDecl *Def, Ts &&... Args) {
Def = Def->getCanonicalDecl();
auto *Func = new Function(*this, Def, std::forward<Ts>(Args)...);
Funcs.insert({Def, std::unique_ptr<Function>(Func)});
return Func;
}
/// Creates an anonymous function.
template <typename... Ts>
Function *createFunction(Ts &&... Args) {
auto *Func = new Function(*this, std::forward<Ts>(Args)...);
AnonFuncs.emplace_back(Func);
return Func;
}
/// Returns a function.
Function *getFunction(const FunctionDecl *F);
/// Returns a record or creates one if it does not exist.
Record *getOrCreateRecord(const RecordDecl *RD);
/// Creates a descriptor for a primitive type.
Descriptor *createDescriptor(const DeclTy &D, PrimType Type,
Descriptor::MetadataSize MDSize = std::nullopt,
bool IsConst = false, bool IsTemporary = false,
bool IsMutable = false) {
return allocateDescriptor(D, Type, MDSize, IsConst, IsTemporary, IsMutable);
}
/// Creates a descriptor for a composite type.
Descriptor *createDescriptor(const DeclTy &D, const Type *Ty,
Descriptor::MetadataSize MDSize = std::nullopt,
bool IsConst = false, bool IsTemporary = false,
bool IsMutable = false,
const Expr *Init = nullptr);
/// Context to manage declaration lifetimes.
class DeclScope {
public:
DeclScope(Program &P, const ValueDecl *VD) : P(P) {
P.startDeclaration(VD);
}
~DeclScope() { P.endDeclaration(); }
private:
Program &P;
};
/// Returns the current declaration ID.
std::optional<unsigned> getCurrentDecl() const {
if (CurrentDeclaration == NoDeclaration)
return std::optional<unsigned>{};
return LastDeclaration;
}
private:
friend class DeclScope;
std::optional<unsigned> createGlobal(const DeclTy &D, QualType Ty,
bool IsStatic, bool IsExtern,
const Expr *Init = nullptr);
/// Reference to the VM context.
Context &Ctx;
/// Mapping from decls to cached bytecode functions.
llvm::DenseMap<const FunctionDecl *, std::unique_ptr<Function>> Funcs;
/// List of anonymous functions.
std::vector<std::unique_ptr<Function>> AnonFuncs;
/// Function relocation locations.
llvm::DenseMap<const FunctionDecl *, std::vector<unsigned>> Relocs;
/// Native pointers referenced by bytecode.
std::vector<const void *> NativePointers;
/// Cached native pointer indices.
llvm::DenseMap<const void *, unsigned> NativePointerIndices;
/// Custom allocator for global storage.
using PoolAllocTy = llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator>;
/// Descriptor + storage for a global object.
///
/// Global objects never go out of scope, thus they do not track pointers.
class Global {
public:
/// Create a global descriptor for string literals.
template <typename... Tys>
Global(Tys... Args) : B(std::forward<Tys>(Args)...) {}
/// Allocates the global in the pool, reserving storate for data.
void *operator new(size_t Meta, PoolAllocTy &Alloc, size_t Data) {
return Alloc.Allocate(Meta + Data, alignof(void *));
}
/// Return a pointer to the data.
std::byte *data() { return B.data(); }
/// Return a pointer to the block.
Block *block() { return &B; }
const Block *block() const { return &B; }
private:
/// Required metadata - does not actually track pointers.
Block B;
};
/// Allocator for globals.
PoolAllocTy Allocator;
/// Global objects.
std::vector<Global *> Globals;
/// Cached global indices.
llvm::DenseMap<const void *, unsigned> GlobalIndices;
/// Mapping from decls to record metadata.
llvm::DenseMap<const RecordDecl *, Record *> Records;
/// Dummy parameter to generate pointers from.
llvm::DenseMap<const ValueDecl *, unsigned> DummyParams;
/// Creates a new descriptor.
template <typename... Ts>
Descriptor *allocateDescriptor(Ts &&... Args) {
return new (Allocator) Descriptor(std::forward<Ts>(Args)...);
}
/// No declaration ID.
static constexpr unsigned NoDeclaration = (unsigned)-1;
/// Last declaration ID.
unsigned LastDeclaration = 0;
/// Current declaration ID.
unsigned CurrentDeclaration = NoDeclaration;
/// Starts evaluating a declaration.
void startDeclaration(const ValueDecl *Decl) {
LastDeclaration += 1;
CurrentDeclaration = LastDeclaration;
}
/// Ends a global declaration.
void endDeclaration() {
CurrentDeclaration = NoDeclaration;
}
public:
/// Dumps the disassembled bytecode to \c llvm::errs().
void dump() const;
void dump(llvm::raw_ostream &OS) const;
};
} // namespace interp
} // namespace clang
#endif
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