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//===--- TypeLocBuilder.h - Type Source Info collector ----------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This file defines TypeLocBuilder, a class for building TypeLocs
// bottom-up.
#include "clang/AST/ASTContext.h"
#include "clang/AST/TypeLoc.h"
namespace clang {
class TypeLocBuilder {
enum { InlineCapacity = 8 * sizeof(SourceLocation) };
/// The underlying location-data buffer. Data grows from the end
/// of the buffer backwards.
char *Buffer;
/// The capacity of the current buffer.
size_t Capacity;
/// The index of the first occupied byte in the buffer.
size_t Index;
#ifndef NDEBUG
/// The last type pushed on this builder.
QualType LastTy;
/// The inline buffer.
enum { BufferMaxAlignment = alignof(void *) };
alignas(BufferMaxAlignment) char InlineBuffer[InlineCapacity];
unsigned NumBytesAtAlign4, NumBytesAtAlign8;
: Buffer(InlineBuffer), Capacity(InlineCapacity), Index(InlineCapacity),
NumBytesAtAlign4(0), NumBytesAtAlign8(0) {}
~TypeLocBuilder() {
if (Buffer != InlineBuffer)
delete[] Buffer;
/// Ensures that this buffer has at least as much capacity as described.
void reserve(size_t Requested) {
if (Requested > Capacity)
// For now, match the request exactly.
/// Pushes a copy of the given TypeLoc onto this builder. The builder
/// must be empty for this to work.
void pushFullCopy(TypeLoc L);
/// Pushes space for a typespec TypeLoc. Invalidates any TypeLocs
/// previously retrieved from this builder.
TypeSpecTypeLoc pushTypeSpec(QualType T) {
size_t LocalSize = TypeSpecTypeLoc::LocalDataSize;
unsigned LocalAlign = TypeSpecTypeLoc::LocalDataAlignment;
return pushImpl(T, LocalSize, LocalAlign).castAs<TypeSpecTypeLoc>();
/// Resets this builder to the newly-initialized state.
void clear() {
#ifndef NDEBUG
LastTy = QualType();
Index = Capacity;
NumBytesAtAlign4 = NumBytesAtAlign8 = 0;
/// Tell the TypeLocBuilder that the type it is storing has been
/// modified in some safe way that doesn't affect type-location information.
void TypeWasModifiedSafely(QualType T) {
#ifndef NDEBUG
LastTy = T;
/// Pushes space for a new TypeLoc of the given type. Invalidates
/// any TypeLocs previously retrieved from this builder.
template <class TyLocType> TyLocType push(QualType T) {
TyLocType Loc = TypeLoc(T, nullptr).castAs<TyLocType>();
size_t LocalSize = Loc.getLocalDataSize();
unsigned LocalAlign = Loc.getLocalDataAlignment();
return pushImpl(T, LocalSize, LocalAlign).castAs<TyLocType>();
/// Creates a TypeSourceInfo for the given type.
TypeSourceInfo *getTypeSourceInfo(ASTContext& Context, QualType T) {
#ifndef NDEBUG
assert(T == LastTy && "type doesn't match last type pushed!");
size_t FullDataSize = Capacity - Index;
TypeSourceInfo *DI = Context.CreateTypeSourceInfo(T, FullDataSize);
memcpy(DI->getTypeLoc().getOpaqueData(), &Buffer[Index], FullDataSize);
return DI;
/// Copies the type-location information to the given AST context and
/// returns a \c TypeLoc referring into the AST context.
TypeLoc getTypeLocInContext(ASTContext &Context, QualType T) {
#ifndef NDEBUG
assert(T == LastTy && "type doesn't match last type pushed!");
size_t FullDataSize = Capacity - Index;
void *Mem = Context.Allocate(FullDataSize);
memcpy(Mem, &Buffer[Index], FullDataSize);
return TypeLoc(T, Mem);
TypeLoc pushImpl(QualType T, size_t LocalSize, unsigned LocalAlignment);
/// Grow to the given capacity.
void grow(size_t NewCapacity);
/// Retrieve a temporary TypeLoc that refers into this \c TypeLocBuilder
/// object.
/// The resulting \c TypeLoc should only be used so long as the
/// \c TypeLocBuilder is active and has not had more type information
/// pushed into it.
TypeLoc getTemporaryTypeLoc(QualType T) {
#ifndef NDEBUG
assert(LastTy == T && "type doesn't match last type pushed!");
return TypeLoc(T, &Buffer[Index]);