llvm-capstone/clang/lib/AST/Interp/Descriptor.cpp
Nandor Licker 950b70dcc7 [Clang Interpreter] Initial patch for the constexpr interpreter
Summary:
This patch introduces the skeleton of the constexpr interpreter,
capable of evaluating a simple constexpr functions consisting of
if statements. The interpreter is described in more detail in the
RFC. Further patches will add more features.

Reviewers: Bigcheese, jfb, rsmith

Subscribers: bruno, uenoku, ldionne, Tyker, thegameg, tschuett, dexonsmith, mgorny, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64146

llvm-svn: 371834
2019-09-13 09:46:16 +00:00

293 lines
10 KiB
C++

//===--- Descriptor.cpp - Types 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
//
//===----------------------------------------------------------------------===//
#include "Descriptor.h"
#include "Pointer.h"
#include "PrimType.h"
#include "Record.h"
using namespace clang;
using namespace clang::interp;
template <typename T>
static void ctorTy(Block *, char *Ptr, bool, bool, bool, Descriptor *) {
new (Ptr) T();
}
template <typename T> static void dtorTy(Block *, char *Ptr, Descriptor *) {
reinterpret_cast<T *>(Ptr)->~T();
}
template <typename T>
static void moveTy(Block *, char *Src, char *Dst, Descriptor *) {
auto *SrcPtr = reinterpret_cast<T *>(Src);
auto *DstPtr = reinterpret_cast<T *>(Dst);
new (DstPtr) T(std::move(*SrcPtr));
}
template <typename T>
static void ctorArrayTy(Block *, char *Ptr, bool, bool, bool, Descriptor *D) {
for (unsigned I = 0, NE = D->getNumElems(); I < NE; ++I) {
new (&reinterpret_cast<T *>(Ptr)[I]) T();
}
}
template <typename T>
static void dtorArrayTy(Block *, char *Ptr, Descriptor *D) {
for (unsigned I = 0, NE = D->getNumElems(); I < NE; ++I) {
reinterpret_cast<T *>(Ptr)[I].~T();
}
}
template <typename T>
static void moveArrayTy(Block *, char *Src, char *Dst, Descriptor *D) {
for (unsigned I = 0, NE = D->getNumElems(); I < NE; ++I) {
auto *SrcPtr = &reinterpret_cast<T *>(Src)[I];
auto *DstPtr = &reinterpret_cast<T *>(Dst)[I];
new (DstPtr) T(std::move(*SrcPtr));
}
}
static void ctorArrayDesc(Block *B, char *Ptr, bool IsConst, bool IsMutable,
bool IsActive, Descriptor *D) {
const unsigned NumElems = D->getNumElems();
const unsigned ElemSize =
D->ElemDesc->getAllocSize() + sizeof(InlineDescriptor);
unsigned ElemOffset = 0;
for (unsigned I = 0; I < NumElems; ++I, ElemOffset += ElemSize) {
auto *ElemPtr = Ptr + ElemOffset;
auto *Desc = reinterpret_cast<InlineDescriptor *>(ElemPtr);
auto *ElemLoc = reinterpret_cast<char *>(Desc + 1);
auto *SD = D->ElemDesc;
Desc->Offset = ElemOffset + sizeof(InlineDescriptor);
Desc->Desc = SD;
Desc->IsInitialized = true;
Desc->IsBase = false;
Desc->IsActive = IsActive;
Desc->IsConst = IsConst || D->IsConst;
Desc->IsMutable = IsMutable || D->IsMutable;
if (auto Fn = D->ElemDesc->CtorFn)
Fn(B, ElemLoc, Desc->IsConst, Desc->IsMutable, IsActive, D->ElemDesc);
}
}
static void dtorArrayDesc(Block *B, char *Ptr, Descriptor *D) {
const unsigned NumElems = D->getNumElems();
const unsigned ElemSize =
D->ElemDesc->getAllocSize() + sizeof(InlineDescriptor);
unsigned ElemOffset = 0;
for (unsigned I = 0; I < NumElems; ++I, ElemOffset += ElemSize) {
auto *ElemPtr = Ptr + ElemOffset;
auto *Desc = reinterpret_cast<InlineDescriptor *>(ElemPtr);
auto *ElemLoc = reinterpret_cast<char *>(Desc + 1);
if (auto Fn = D->ElemDesc->DtorFn)
Fn(B, ElemLoc, D->ElemDesc);
}
}
static void moveArrayDesc(Block *B, char *Src, char *Dst, Descriptor *D) {
const unsigned NumElems = D->getNumElems();
const unsigned ElemSize =
D->ElemDesc->getAllocSize() + sizeof(InlineDescriptor);
unsigned ElemOffset = 0;
for (unsigned I = 0; I < NumElems; ++I, ElemOffset += ElemSize) {
auto *SrcPtr = Src + ElemOffset;
auto *DstPtr = Dst + ElemOffset;
auto *SrcDesc = reinterpret_cast<InlineDescriptor *>(SrcPtr);
auto *SrcElemLoc = reinterpret_cast<char *>(SrcDesc + 1);
auto *DstDesc = reinterpret_cast<InlineDescriptor *>(DstPtr);
auto *DstElemLoc = reinterpret_cast<char *>(DstDesc + 1);
*DstDesc = *SrcDesc;
if (auto Fn = D->ElemDesc->MoveFn)
Fn(B, SrcElemLoc, DstElemLoc, D->ElemDesc);
}
}
static void ctorRecord(Block *B, char *Ptr, bool IsConst, bool IsMutable,
bool IsActive, Descriptor *D) {
const bool IsUnion = D->ElemRecord->isUnion();
auto CtorSub = [=](unsigned SubOff, Descriptor *F, bool IsBase) {
auto *Desc = reinterpret_cast<InlineDescriptor *>(Ptr + SubOff) - 1;
Desc->Offset = SubOff;
Desc->Desc = F;
Desc->IsInitialized = (B->isStatic() || F->IsArray) && !IsBase;
Desc->IsBase = IsBase;
Desc->IsActive = IsActive && !IsUnion;
Desc->IsConst = IsConst || F->IsConst;
Desc->IsMutable = IsMutable || F->IsMutable;
if (auto Fn = F->CtorFn)
Fn(B, Ptr + SubOff, Desc->IsConst, Desc->IsMutable, Desc->IsActive, F);
};
for (const auto &B : D->ElemRecord->bases())
CtorSub(B.Offset, B.Desc, /*isBase=*/true);
for (const auto &F : D->ElemRecord->fields())
CtorSub(F.Offset, F.Desc, /*isBase=*/false);
for (const auto &V : D->ElemRecord->virtual_bases())
CtorSub(V.Offset, V.Desc, /*isBase=*/true);
}
static void dtorRecord(Block *B, char *Ptr, Descriptor *D) {
auto DtorSub = [=](unsigned SubOff, Descriptor *F) {
if (auto Fn = F->DtorFn)
Fn(B, Ptr + SubOff, F);
};
for (const auto &F : D->ElemRecord->bases())
DtorSub(F.Offset, F.Desc);
for (const auto &F : D->ElemRecord->fields())
DtorSub(F.Offset, F.Desc);
for (const auto &F : D->ElemRecord->virtual_bases())
DtorSub(F.Offset, F.Desc);
}
static void moveRecord(Block *B, char *Src, char *Dst, Descriptor *D) {
for (const auto &F : D->ElemRecord->fields()) {
auto FieldOff = F.Offset;
auto FieldDesc = F.Desc;
*(reinterpret_cast<Descriptor **>(Dst + FieldOff) - 1) = FieldDesc;
if (auto Fn = FieldDesc->MoveFn)
Fn(B, Src + FieldOff, Dst + FieldOff, FieldDesc);
}
}
static BlockCtorFn getCtorPrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return ctorTy<T>, return nullptr);
}
static BlockDtorFn getDtorPrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return dtorTy<T>, return nullptr);
}
static BlockMoveFn getMovePrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return moveTy<T>, return nullptr);
}
static BlockCtorFn getCtorArrayPrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return ctorArrayTy<T>, return nullptr);
}
static BlockDtorFn getDtorArrayPrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return dtorArrayTy<T>, return nullptr);
}
static BlockMoveFn getMoveArrayPrim(PrimType Type) {
COMPOSITE_TYPE_SWITCH(Type, return moveArrayTy<T>, return nullptr);
}
Descriptor::Descriptor(const DeclTy &D, PrimType Type, bool IsConst,
bool IsTemporary, bool IsMutable)
: Source(D), ElemSize(primSize(Type)), Size(ElemSize), AllocSize(Size),
IsConst(IsConst), IsMutable(IsMutable), IsTemporary(IsTemporary),
CtorFn(getCtorPrim(Type)), DtorFn(getDtorPrim(Type)),
MoveFn(getMovePrim(Type)) {
assert(Source && "Missing source");
}
Descriptor::Descriptor(const DeclTy &D, PrimType Type, size_t NumElems,
bool IsConst, bool IsTemporary, bool IsMutable)
: Source(D), ElemSize(primSize(Type)), Size(ElemSize * NumElems),
AllocSize(align(Size) + sizeof(InitMap *)), IsConst(IsConst),
IsMutable(IsMutable), IsTemporary(IsTemporary), IsArray(true),
CtorFn(getCtorArrayPrim(Type)), DtorFn(getDtorArrayPrim(Type)),
MoveFn(getMoveArrayPrim(Type)) {
assert(Source && "Missing source");
}
Descriptor::Descriptor(const DeclTy &D, PrimType Type, bool IsTemporary,
UnknownSize)
: Source(D), ElemSize(primSize(Type)), Size(UnknownSizeMark),
AllocSize(alignof(void *)), IsConst(true), IsMutable(false),
IsTemporary(IsTemporary), IsArray(true), CtorFn(getCtorArrayPrim(Type)),
DtorFn(getDtorArrayPrim(Type)), MoveFn(getMoveArrayPrim(Type)) {
assert(Source && "Missing source");
}
Descriptor::Descriptor(const DeclTy &D, Descriptor *Elem, unsigned NumElems,
bool IsConst, bool IsTemporary, bool IsMutable)
: Source(D), ElemSize(Elem->getAllocSize() + sizeof(InlineDescriptor)),
Size(ElemSize * NumElems),
AllocSize(std::max<size_t>(alignof(void *), Size)), ElemDesc(Elem),
IsConst(IsConst), IsMutable(IsMutable), IsTemporary(IsTemporary),
IsArray(true), CtorFn(ctorArrayDesc), DtorFn(dtorArrayDesc),
MoveFn(moveArrayDesc) {
assert(Source && "Missing source");
}
Descriptor::Descriptor(const DeclTy &D, Descriptor *Elem, bool IsTemporary,
UnknownSize)
: Source(D), ElemSize(Elem->getAllocSize() + sizeof(InlineDescriptor)),
Size(UnknownSizeMark), AllocSize(alignof(void *)), ElemDesc(Elem),
IsConst(true), IsMutable(false), IsTemporary(IsTemporary), IsArray(true),
CtorFn(ctorArrayDesc), DtorFn(dtorArrayDesc), MoveFn(moveArrayDesc) {
assert(Source && "Missing source");
}
Descriptor::Descriptor(const DeclTy &D, Record *R, bool IsConst,
bool IsTemporary, bool IsMutable)
: Source(D), ElemSize(std::max<size_t>(alignof(void *), R->getFullSize())),
Size(ElemSize), AllocSize(Size), ElemRecord(R), IsConst(IsConst),
IsMutable(IsMutable), IsTemporary(IsTemporary), CtorFn(ctorRecord),
DtorFn(dtorRecord), MoveFn(moveRecord) {
assert(Source && "Missing source");
}
QualType Descriptor::getType() const {
if (auto *E = asExpr())
return E->getType();
if (auto *D = asValueDecl())
return D->getType();
llvm_unreachable("Invalid descriptor type");
}
SourceLocation Descriptor::getLocation() const {
if (auto *D = Source.dyn_cast<const Decl *>())
return D->getLocation();
if (auto *E = Source.dyn_cast<const Expr *>())
return E->getExprLoc();
llvm_unreachable("Invalid descriptor type");
}
InitMap::InitMap(unsigned N) : UninitFields(N) {
for (unsigned I = 0; I < N / PER_FIELD; ++I) {
data()[I] = 0;
}
}
InitMap::T *InitMap::data() {
auto *Start = reinterpret_cast<char *>(this) + align(sizeof(InitMap));
return reinterpret_cast<T *>(Start);
}
bool InitMap::initialize(unsigned I) {
unsigned Bucket = I / PER_FIELD;
unsigned Mask = 1ull << static_cast<uint64_t>(I % PER_FIELD);
if (!(data()[Bucket] & Mask)) {
data()[Bucket] |= Mask;
UninitFields -= 1;
}
return UninitFields == 0;
}
bool InitMap::isInitialized(unsigned I) {
unsigned Bucket = I / PER_FIELD;
unsigned Mask = 1ull << static_cast<uint64_t>(I % PER_FIELD);
return data()[Bucket] & Mask;
}
InitMap *InitMap::allocate(unsigned N) {
const size_t NumFields = ((N + PER_FIELD - 1) / PER_FIELD);
const size_t Size = align(sizeof(InitMap)) + NumFields * PER_FIELD;
return new (malloc(Size)) InitMap(N);
}