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llvm-project/clang/lib/Sema/SemaStmtAsm.cpp
Matheus Izvekov 91cdd35008
[clang] Improve nested name specifier AST representation (#147835) 
This is a major change on how we represent nested name qualifications in
the AST.

* The nested name specifier itself and how it's stored is changed. The
prefixes for types are handled within the type hierarchy, which makes
canonicalization for them super cheap, no memory allocation required.
Also translating a type into nested name specifier form becomes a no-op.
An identifier is stored as a DependentNameType. The nested name
specifier gains a lightweight handle class, to be used instead of
passing around pointers, which is similar to what is implemented for
TemplateName. There is still one free bit available, and this handle can
be used within a PointerUnion and PointerIntPair, which should keep
bit-packing aficionados happy.
* The ElaboratedType node is removed, all type nodes in which it could
previously apply to can now store the elaborated keyword and name
qualifier, tail allocating when present.
* TagTypes can now point to the exact declaration found when producing
these, as opposed to the previous situation of there only existing one
TagType per entity. This increases the amount of type sugar retained,
and can have several applications, for example in tracking module
ownership, and other tools which care about source file origins, such as
IWYU. These TagTypes are lazily allocated, in order to limit the
increase in AST size.

This patch offers a great performance benefit.

It greatly improves compilation time for
[stdexec](https://github.com/NVIDIA/stdexec). For one datapoint, for
`test_on2.cpp` in that project, which is the slowest compiling test,
this patch improves `-c` compilation time by about 7.2%, with the
`-fsyntax-only` improvement being at ~12%.

This has great results on compile-time-tracker as well:

![image](https://github.com/user-attachments/assets/700dce98-2cab-4aa8-97d1-b038c0bee831)

This patch also further enables other optimziations in the future, and
will reduce the performance impact of template specialization resugaring
when that lands.

It has some other miscelaneous drive-by fixes.

About the review: Yes the patch is huge, sorry about that. Part of the
reason is that I started by the nested name specifier part, before the
ElaboratedType part, but that had a huge performance downside, as
ElaboratedType is a big performance hog. I didn't have the steam to go
back and change the patch after the fact.

There is also a lot of internal API changes, and it made sense to remove
ElaboratedType in one go, versus removing it from one type at a time, as
that would present much more churn to the users. Also, the nested name
specifier having a different API avoids missing changes related to how
prefixes work now, which could make existing code compile but not work.

How to review: The important changes are all in
`clang/include/clang/AST` and `clang/lib/AST`, with also important
changes in `clang/lib/Sema/TreeTransform.h`.

The rest and bulk of the changes are mostly consequences of the changes
in API.

PS: TagType::getDecl is renamed to `getOriginalDecl` in this patch, just
for easier to rebasing. I plan to rename it back after this lands.

Fixes #136624
Fixes https://github.com/llvm/llvm-project/issues/43179
Fixes https://github.com/llvm/llvm-project/issues/68670
Fixes https://github.com/llvm/llvm-project/issues/92757
2025-08-09 05:06:53 -03:00

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//===--- SemaStmtAsm.cpp - Semantic Analysis for Asm Statements -----------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for inline asm statements.
//
//===----------------------------------------------------------------------===//
#include "clang/AST/ExprCXX.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Initialization.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/Ownership.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/ScopeInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include <optional>
using namespace clang;
using namespace sema;
/// Remove the upper-level LValueToRValue cast from an expression.
static void removeLValueToRValueCast(Expr *E) {
Expr *Parent = E;
Expr *ExprUnderCast = nullptr;
SmallVector<Expr *, 8> ParentsToUpdate;
while (true) {
ParentsToUpdate.push_back(Parent);
if (auto *ParenE = dyn_cast<ParenExpr>(Parent)) {
Parent = ParenE->getSubExpr();
continue;
}
Expr *Child = nullptr;
CastExpr *ParentCast = dyn_cast<CastExpr>(Parent);
if (ParentCast)
Child = ParentCast->getSubExpr();
else
return;
if (auto *CastE = dyn_cast<CastExpr>(Child))
if (CastE->getCastKind() == CK_LValueToRValue) {
ExprUnderCast = CastE->getSubExpr();
// LValueToRValue cast inside GCCAsmStmt requires an explicit cast.
ParentCast->setSubExpr(ExprUnderCast);
break;
}
Parent = Child;
}
// Update parent expressions to have same ValueType as the underlying.
assert(ExprUnderCast &&
"Should be reachable only if LValueToRValue cast was found!");
auto ValueKind = ExprUnderCast->getValueKind();
for (Expr *E : ParentsToUpdate)
E->setValueKind(ValueKind);
}
/// Emit a warning about usage of "noop"-like casts for lvalues (GNU extension)
/// and fix the argument with removing LValueToRValue cast from the expression.
static void emitAndFixInvalidAsmCastLValue(const Expr *LVal, Expr *BadArgument,
Sema &S) {
S.Diag(LVal->getBeginLoc(), diag::warn_invalid_asm_cast_lvalue)
<< BadArgument->getSourceRange();
removeLValueToRValueCast(BadArgument);
}
/// CheckAsmLValue - GNU C has an extremely ugly extension whereby they silently
/// ignore "noop" casts in places where an lvalue is required by an inline asm.
/// We emulate this behavior when -fheinous-gnu-extensions is specified, but
/// provide a strong guidance to not use it.
///
/// This method checks to see if the argument is an acceptable l-value and
/// returns false if it is a case we can handle.
static bool CheckAsmLValue(Expr *E, Sema &S) {
// Type dependent expressions will be checked during instantiation.
if (E->isTypeDependent())
return false;
if (E->isLValue())
return false; // Cool, this is an lvalue.
// Okay, this is not an lvalue, but perhaps it is the result of a cast that we
// are supposed to allow.
const Expr *E2 = E->IgnoreParenNoopCasts(S.Context);
if (E != E2 && E2->isLValue()) {
emitAndFixInvalidAsmCastLValue(E2, E, S);
// Accept, even if we emitted an error diagnostic.
return false;
}
// None of the above, just randomly invalid non-lvalue.
return true;
}
/// isOperandMentioned - Return true if the specified operand # is mentioned
/// anywhere in the decomposed asm string.
static bool
isOperandMentioned(unsigned OpNo,
ArrayRef<GCCAsmStmt::AsmStringPiece> AsmStrPieces) {
for (unsigned p = 0, e = AsmStrPieces.size(); p != e; ++p) {
const GCCAsmStmt::AsmStringPiece &Piece = AsmStrPieces[p];
if (!Piece.isOperand())
continue;
// If this is a reference to the input and if the input was the smaller
// one, then we have to reject this asm.
if (Piece.getOperandNo() == OpNo)
return true;
}
return false;
}
static bool CheckNakedParmReference(Expr *E, Sema &S) {
FunctionDecl *Func = dyn_cast<FunctionDecl>(S.CurContext);
if (!Func)
return false;
if (!Func->hasAttr<NakedAttr>())
return false;
SmallVector<Expr*, 4> WorkList;
WorkList.push_back(E);
while (WorkList.size()) {
Expr *E = WorkList.pop_back_val();
if (isa<CXXThisExpr>(E)) {
S.Diag(E->getBeginLoc(), diag::err_asm_naked_this_ref);
S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
return true;
}
if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
if (isa<ParmVarDecl>(DRE->getDecl())) {
S.Diag(DRE->getBeginLoc(), diag::err_asm_naked_parm_ref);
S.Diag(Func->getAttr<NakedAttr>()->getLocation(), diag::note_attribute);
return true;
}
}
for (Stmt *Child : E->children()) {
if (Expr *E = dyn_cast_or_null<Expr>(Child))
WorkList.push_back(E);
}
}
return false;
}
/// Returns true if given expression is not compatible with inline
/// assembly's memory constraint; false otherwise.
static bool checkExprMemoryConstraintCompat(Sema &S, Expr *E,
TargetInfo::ConstraintInfo &Info,
bool is_input_expr) {
enum {
ExprBitfield = 0,
ExprVectorElt,
ExprGlobalRegVar,
ExprSafeType
} EType = ExprSafeType;
// Bitfields, vector elements and global register variables are not
// compatible.
if (E->refersToBitField())
EType = ExprBitfield;
else if (E->refersToVectorElement())
EType = ExprVectorElt;
else if (E->refersToGlobalRegisterVar())
EType = ExprGlobalRegVar;
if (EType != ExprSafeType) {
S.Diag(E->getBeginLoc(), diag::err_asm_non_addr_value_in_memory_constraint)
<< EType << is_input_expr << Info.getConstraintStr()
<< E->getSourceRange();
return true;
}
return false;
}
// Extracting the register name from the Expression value,
// if there is no register name to extract, returns ""
static StringRef extractRegisterName(const Expr *Expression,
const TargetInfo &Target) {
Expression = Expression->IgnoreImpCasts();
if (const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(Expression)) {
// Handle cases where the expression is a variable
const VarDecl *Variable = dyn_cast<VarDecl>(AsmDeclRef->getDecl());
if (Variable && Variable->getStorageClass() == SC_Register) {
if (AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>())
if (Target.isValidGCCRegisterName(Attr->getLabel()))
return Target.getNormalizedGCCRegisterName(Attr->getLabel(), true);
}
}
return "";
}
// Checks if there is a conflict between the input and output lists with the
// clobbers list. If there's a conflict, returns the location of the
// conflicted clobber, else returns nullptr
static SourceLocation
getClobberConflictLocation(MultiExprArg Exprs, Expr **Constraints,
Expr **Clobbers, int NumClobbers, unsigned NumLabels,
const TargetInfo &Target, ASTContext &Cont) {
llvm::StringSet<> InOutVars;
// Collect all the input and output registers from the extended asm
// statement in order to check for conflicts with the clobber list
for (unsigned int i = 0; i < Exprs.size() - NumLabels; ++i) {
std::string Constraint =
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Constraints[i]);
StringRef InOutReg = Target.getConstraintRegister(
Constraint, extractRegisterName(Exprs[i], Target));
if (InOutReg != "")
InOutVars.insert(InOutReg);
}
// Check for each item in the clobber list if it conflicts with the input
// or output
for (int i = 0; i < NumClobbers; ++i) {
std::string Clobber =
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Clobbers[i]);
// We only check registers, therefore we don't check cc and memory
// clobbers
if (Clobber == "cc" || Clobber == "memory" || Clobber == "unwind")
continue;
Clobber = Target.getNormalizedGCCRegisterName(Clobber, true);
// Go over the output's registers we collected
if (InOutVars.count(Clobber))
return Clobbers[i]->getBeginLoc();
}
return SourceLocation();
}
ExprResult Sema::ActOnGCCAsmStmtString(Expr *Expr, bool ForAsmLabel) {
if (!Expr)
return ExprError();
if (auto *SL = dyn_cast<StringLiteral>(Expr)) {
assert(SL->isOrdinary());
if (ForAsmLabel && SL->getString().empty()) {
Diag(Expr->getBeginLoc(), diag::err_asm_operand_empty_string)
<< SL->getSourceRange();
}
return SL;
}
if (DiagnoseUnexpandedParameterPack(Expr))
return ExprError();
if (Expr->getDependence() != ExprDependence::None)
return Expr;
APValue V;
if (!EvaluateAsString(Expr, V, getASTContext(), StringEvaluationContext::Asm,
/*ErrorOnInvalid=*/true))
return ExprError();
if (ForAsmLabel && V.getArrayInitializedElts() == 0) {
Diag(Expr->getBeginLoc(), diag::err_asm_operand_empty_string);
}
ConstantExpr *Res = ConstantExpr::Create(getASTContext(), Expr,
ConstantResultStorageKind::APValue);
Res->SetResult(V, getASTContext());
return Res;
}
StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
bool IsVolatile, unsigned NumOutputs,
unsigned NumInputs, IdentifierInfo **Names,
MultiExprArg constraints, MultiExprArg Exprs,
Expr *asmString, MultiExprArg clobbers,
unsigned NumLabels,
SourceLocation RParenLoc) {
unsigned NumClobbers = clobbers.size();
SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos;
FunctionDecl *FD = dyn_cast<FunctionDecl>(getCurLexicalContext());
llvm::StringMap<bool> FeatureMap;
Context.getFunctionFeatureMap(FeatureMap, FD);
auto CreateGCCAsmStmt = [&] {
return new (Context)
GCCAsmStmt(Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs,
Names, constraints.data(), Exprs.data(), asmString,
NumClobbers, clobbers.data(), NumLabels, RParenLoc);
};
if (asmString->getDependence() != ExprDependence::None ||
llvm::any_of(
constraints,
[](Expr *E) { return E->getDependence() != ExprDependence::None; }) ||
llvm::any_of(clobbers, [](Expr *E) {
return E->getDependence() != ExprDependence::None;
}))
return CreateGCCAsmStmt();
for (unsigned i = 0; i != NumOutputs; i++) {
Expr *Constraint = constraints[i];
StringRef OutputName;
if (Names[i])
OutputName = Names[i]->getName();
std::string ConstraintStr =
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Constraint);
TargetInfo::ConstraintInfo Info(ConstraintStr, OutputName);
if (!Context.getTargetInfo().validateOutputConstraint(Info) &&
!(LangOpts.HIPStdPar && LangOpts.CUDAIsDevice)) {
targetDiag(Constraint->getBeginLoc(),
diag::err_asm_invalid_output_constraint)
<< Info.getConstraintStr();
return CreateGCCAsmStmt();
}
ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
if (ER.isInvalid())
return StmtError();
Exprs[i] = ER.get();
// Check that the output exprs are valid lvalues.
Expr *OutputExpr = Exprs[i];
// Referring to parameters is not allowed in naked functions.
if (CheckNakedParmReference(OutputExpr, *this))
return StmtError();
// Check that the output expression is compatible with memory constraint.
if (Info.allowsMemory() &&
checkExprMemoryConstraintCompat(*this, OutputExpr, Info, false))
return StmtError();
// Disallow bit-precise integer types, since the backends tend to have
// difficulties with abnormal sizes.
if (OutputExpr->getType()->isBitIntType())
return StmtError(
Diag(OutputExpr->getBeginLoc(), diag::err_asm_invalid_type)
<< OutputExpr->getType() << 0 /*Input*/
<< OutputExpr->getSourceRange());
OutputConstraintInfos.push_back(Info);
// If this is dependent, just continue.
if (OutputExpr->isTypeDependent())
continue;
Expr::isModifiableLvalueResult IsLV =
OutputExpr->isModifiableLvalue(Context, /*Loc=*/nullptr);
switch (IsLV) {
case Expr::MLV_Valid:
// Cool, this is an lvalue.
break;
case Expr::MLV_ArrayType:
// This is OK too.
break;
case Expr::MLV_LValueCast: {
const Expr *LVal = OutputExpr->IgnoreParenNoopCasts(Context);
emitAndFixInvalidAsmCastLValue(LVal, OutputExpr, *this);
// Accept, even if we emitted an error diagnostic.
break;
}
case Expr::MLV_IncompleteType:
case Expr::MLV_IncompleteVoidType:
if (RequireCompleteType(OutputExpr->getBeginLoc(), Exprs[i]->getType(),
diag::err_dereference_incomplete_type))
return StmtError();
[[fallthrough]];
default:
return StmtError(Diag(OutputExpr->getBeginLoc(),
diag::err_asm_invalid_lvalue_in_output)
<< OutputExpr->getSourceRange());
}
unsigned Size = Context.getTypeSize(OutputExpr->getType());
if (!Context.getTargetInfo().validateOutputSize(
FeatureMap,
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Constraint),
Size)) {
targetDiag(OutputExpr->getBeginLoc(), diag::err_asm_invalid_output_size)
<< Info.getConstraintStr();
return CreateGCCAsmStmt();
}
}
SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos;
for (unsigned i = NumOutputs, e = NumOutputs + NumInputs; i != e; i++) {
Expr *Constraint = constraints[i];
StringRef InputName;
if (Names[i])
InputName = Names[i]->getName();
std::string ConstraintStr =
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Constraint);
TargetInfo::ConstraintInfo Info(ConstraintStr, InputName);
if (!Context.getTargetInfo().validateInputConstraint(OutputConstraintInfos,
Info)) {
targetDiag(Constraint->getBeginLoc(),
diag::err_asm_invalid_input_constraint)
<< Info.getConstraintStr();
return CreateGCCAsmStmt();
}
ExprResult ER = CheckPlaceholderExpr(Exprs[i]);
if (ER.isInvalid())
return StmtError();
Exprs[i] = ER.get();
Expr *InputExpr = Exprs[i];
if (InputExpr->getType()->isMemberPointerType())
return StmtError(Diag(InputExpr->getBeginLoc(),
diag::err_asm_pmf_through_constraint_not_permitted)
<< InputExpr->getSourceRange());
// Referring to parameters is not allowed in naked functions.
if (CheckNakedParmReference(InputExpr, *this))
return StmtError();
// Check that the input expression is compatible with memory constraint.
if (Info.allowsMemory() &&
checkExprMemoryConstraintCompat(*this, InputExpr, Info, true))
return StmtError();
// Only allow void types for memory constraints.
if (Info.allowsMemory() && !Info.allowsRegister()) {
if (CheckAsmLValue(InputExpr, *this))
return StmtError(Diag(InputExpr->getBeginLoc(),
diag::err_asm_invalid_lvalue_in_input)
<< Info.getConstraintStr()
<< InputExpr->getSourceRange());
} else {
ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
if (Result.isInvalid())
return StmtError();
InputExpr = Exprs[i] = Result.get();
if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
if (!InputExpr->isValueDependent()) {
Expr::EvalResult EVResult;
if (InputExpr->EvaluateAsRValue(EVResult, Context, true)) {
// For compatibility with GCC, we also allow pointers that would be
// integral constant expressions if they were cast to int.
llvm::APSInt IntResult;
if (EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
Context))
if (!Info.isValidAsmImmediate(IntResult))
return StmtError(
Diag(InputExpr->getBeginLoc(),
diag::err_invalid_asm_value_for_constraint)
<< toString(IntResult, 10) << Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
}
}
}
if (Info.allowsRegister()) {
if (InputExpr->getType()->isVoidType()) {
return StmtError(
Diag(InputExpr->getBeginLoc(), diag::err_asm_invalid_type_in_input)
<< InputExpr->getType() << Info.getConstraintStr()
<< InputExpr->getSourceRange());
}
}
if (InputExpr->getType()->isBitIntType())
return StmtError(
Diag(InputExpr->getBeginLoc(), diag::err_asm_invalid_type)
<< InputExpr->getType() << 1 /*Output*/
<< InputExpr->getSourceRange());
InputConstraintInfos.push_back(Info);
const Type *Ty = Exprs[i]->getType().getTypePtr();
if (Ty->isDependentType())
continue;
if (!Ty->isVoidType() || !Info.allowsMemory())
if (RequireCompleteType(InputExpr->getBeginLoc(), Exprs[i]->getType(),
diag::err_dereference_incomplete_type))
return StmtError();
unsigned Size = Context.getTypeSize(Ty);
if (!Context.getTargetInfo().validateInputSize(FeatureMap, ConstraintStr,
Size))
return targetDiag(InputExpr->getBeginLoc(),
diag::err_asm_invalid_input_size)
<< Info.getConstraintStr();
}
std::optional<SourceLocation> UnwindClobberLoc;
// Check that the clobbers are valid.
for (unsigned i = 0; i != NumClobbers; i++) {
Expr *ClobberExpr = clobbers[i];
std::string Clobber =
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(ClobberExpr);
if (!Context.getTargetInfo().isValidClobber(Clobber)) {
targetDiag(ClobberExpr->getBeginLoc(),
diag::err_asm_unknown_register_name)
<< Clobber;
return new (Context) GCCAsmStmt(
Context, AsmLoc, IsSimple, IsVolatile, NumOutputs, NumInputs, Names,
constraints.data(), Exprs.data(), asmString, NumClobbers,
clobbers.data(), NumLabels, RParenLoc);
}
if (Clobber == "unwind") {
UnwindClobberLoc = ClobberExpr->getBeginLoc();
}
}
// Using unwind clobber and asm-goto together is not supported right now.
if (UnwindClobberLoc && NumLabels > 0) {
targetDiag(*UnwindClobberLoc, diag::err_asm_unwind_and_goto);
return CreateGCCAsmStmt();
}
GCCAsmStmt *NS = CreateGCCAsmStmt();
// Validate the asm string, ensuring it makes sense given the operands we
// have.
auto GetLocation = [this](const Expr *Str, unsigned Offset) {
if (auto *SL = dyn_cast<StringLiteral>(Str))
return getLocationOfStringLiteralByte(SL, Offset);
return Str->getBeginLoc();
};
SmallVector<GCCAsmStmt::AsmStringPiece, 8> Pieces;
unsigned DiagOffs;
if (unsigned DiagID = NS->AnalyzeAsmString(Pieces, Context, DiagOffs)) {
targetDiag(GetLocation(asmString, DiagOffs), DiagID)
<< asmString->getSourceRange();
return NS;
}
// Validate constraints and modifiers.
for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
if (!Piece.isOperand()) continue;
// Look for the correct constraint index.
unsigned ConstraintIdx = Piece.getOperandNo();
unsigned NumOperands = NS->getNumOutputs() + NS->getNumInputs();
// Labels are the last in the Exprs list.
if (NS->isAsmGoto() && ConstraintIdx >= NumOperands)
continue;
// Look for the (ConstraintIdx - NumOperands + 1)th constraint with
// modifier '+'.
if (ConstraintIdx >= NumOperands) {
unsigned I = 0, E = NS->getNumOutputs();
for (unsigned Cnt = ConstraintIdx - NumOperands; I != E; ++I)
if (OutputConstraintInfos[I].isReadWrite() && Cnt-- == 0) {
ConstraintIdx = I;
break;
}
assert(I != E && "Invalid operand number should have been caught in "
" AnalyzeAsmString");
}
// Now that we have the right indexes go ahead and check.
Expr *Constraint = constraints[ConstraintIdx];
const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
if (Ty->isDependentType() || Ty->isIncompleteType())
continue;
unsigned Size = Context.getTypeSize(Ty);
std::string SuggestedModifier;
if (!Context.getTargetInfo().validateConstraintModifier(
GCCAsmStmt::ExtractStringFromGCCAsmStmtComponent(Constraint),
Piece.getModifier(), Size, SuggestedModifier)) {
targetDiag(Exprs[ConstraintIdx]->getBeginLoc(),
diag::warn_asm_mismatched_size_modifier);
if (!SuggestedModifier.empty()) {
auto B = targetDiag(Piece.getRange().getBegin(),
diag::note_asm_missing_constraint_modifier)
<< SuggestedModifier;
if (isa<StringLiteral>(Constraint)) {
SuggestedModifier = "%" + SuggestedModifier + Piece.getString();
B << FixItHint::CreateReplacement(Piece.getRange(),
SuggestedModifier);
}
}
}
}
// Validate tied input operands for type mismatches.
unsigned NumAlternatives = ~0U;
for (unsigned i = 0, e = OutputConstraintInfos.size(); i != e; ++i) {
TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
StringRef ConstraintStr = Info.getConstraintStr();
unsigned AltCount = ConstraintStr.count(',') + 1;
if (NumAlternatives == ~0U) {
NumAlternatives = AltCount;
} else if (NumAlternatives != AltCount) {
targetDiag(NS->getOutputExpr(i)->getBeginLoc(),
diag::err_asm_unexpected_constraint_alternatives)
<< NumAlternatives << AltCount;
return NS;
}
}
SmallVector<size_t, 4> InputMatchedToOutput(OutputConstraintInfos.size(),
~0U);
for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
StringRef ConstraintStr = Info.getConstraintStr();
unsigned AltCount = ConstraintStr.count(',') + 1;
if (NumAlternatives == ~0U) {
NumAlternatives = AltCount;
} else if (NumAlternatives != AltCount) {
targetDiag(NS->getInputExpr(i)->getBeginLoc(),
diag::err_asm_unexpected_constraint_alternatives)
<< NumAlternatives << AltCount;
return NS;
}
// If this is a tied constraint, verify that the output and input have
// either exactly the same type, or that they are int/ptr operands with the
// same size (int/long, int*/long, are ok etc).
if (!Info.hasTiedOperand()) continue;
unsigned TiedTo = Info.getTiedOperand();
unsigned InputOpNo = i+NumOutputs;
Expr *OutputExpr = Exprs[TiedTo];
Expr *InputExpr = Exprs[InputOpNo];
// Make sure no more than one input constraint matches each output.
assert(TiedTo < InputMatchedToOutput.size() && "TiedTo value out of range");
if (InputMatchedToOutput[TiedTo] != ~0U) {
targetDiag(NS->getInputExpr(i)->getBeginLoc(),
diag::err_asm_input_duplicate_match)
<< TiedTo;
targetDiag(NS->getInputExpr(InputMatchedToOutput[TiedTo])->getBeginLoc(),
diag::note_asm_input_duplicate_first)
<< TiedTo;
return NS;
}
InputMatchedToOutput[TiedTo] = i;
if (OutputExpr->isTypeDependent() || InputExpr->isTypeDependent())
continue;
QualType InTy = InputExpr->getType();
QualType OutTy = OutputExpr->getType();
if (Context.hasSameType(InTy, OutTy))
continue; // All types can be tied to themselves.
// Decide if the input and output are in the same domain (integer/ptr or
// floating point.
enum AsmDomain {
AD_Int, AD_FP, AD_Other
} InputDomain, OutputDomain;
if (InTy->isIntegerType() || InTy->isPointerType())
InputDomain = AD_Int;
else if (InTy->isRealFloatingType())
InputDomain = AD_FP;
else
InputDomain = AD_Other;
if (OutTy->isIntegerType() || OutTy->isPointerType())
OutputDomain = AD_Int;
else if (OutTy->isRealFloatingType())
OutputDomain = AD_FP;
else
OutputDomain = AD_Other;
// They are ok if they are the same size and in the same domain. This
// allows tying things like:
// void* to int*
// void* to int if they are the same size.
// double to long double if they are the same size.
//
uint64_t OutSize = Context.getTypeSize(OutTy);
uint64_t InSize = Context.getTypeSize(InTy);
if (OutSize == InSize && InputDomain == OutputDomain &&
InputDomain != AD_Other)
continue;
// If the smaller input/output operand is not mentioned in the asm string,
// then we can promote the smaller one to a larger input and the asm string
// won't notice.
bool SmallerValueMentioned = false;
// If this is a reference to the input and if the input was the smaller
// one, then we have to reject this asm.
if (isOperandMentioned(InputOpNo, Pieces)) {
// This is a use in the asm string of the smaller operand. Since we
// codegen this by promoting to a wider value, the asm will get printed
// "wrong".
SmallerValueMentioned |= InSize < OutSize;
}
if (isOperandMentioned(TiedTo, Pieces)) {
// If this is a reference to the output, and if the output is the larger
// value, then it's ok because we'll promote the input to the larger type.
SmallerValueMentioned |= OutSize < InSize;
}
// If the input is an integer register while the output is floating point,
// or vice-versa, there is no way they can work together.
bool FPTiedToInt = (InputDomain == AD_FP) ^ (OutputDomain == AD_FP);
// If the smaller value wasn't mentioned in the asm string, and if the
// output was a register, just extend the shorter one to the size of the
// larger one.
if (!SmallerValueMentioned && !FPTiedToInt && InputDomain != AD_Other &&
OutputConstraintInfos[TiedTo].allowsRegister()) {
// FIXME: GCC supports the OutSize to be 128 at maximum. Currently codegen
// crash when the size larger than the register size. So we limit it here.
if (OutTy->isStructureType() &&
Context.getIntTypeForBitwidth(OutSize, /*Signed*/ false).isNull()) {
targetDiag(OutputExpr->getExprLoc(), diag::err_store_value_to_reg);
return NS;
}
continue;
}
// Either both of the operands were mentioned or the smaller one was
// mentioned. One more special case that we'll allow: if the tied input is
// integer, unmentioned, and is a constant, then we'll allow truncating it
// down to the size of the destination.
if (InputDomain == AD_Int && OutputDomain == AD_Int &&
!isOperandMentioned(InputOpNo, Pieces) &&
InputExpr->isEvaluatable(Context)) {
CastKind castKind =
(OutTy->isBooleanType() ? CK_IntegralToBoolean : CK_IntegralCast);
InputExpr = ImpCastExprToType(InputExpr, OutTy, castKind).get();
Exprs[InputOpNo] = InputExpr;
NS->setInputExpr(i, InputExpr);
continue;
}
targetDiag(InputExpr->getBeginLoc(), diag::err_asm_tying_incompatible_types)
<< InTy << OutTy << OutputExpr->getSourceRange()
<< InputExpr->getSourceRange();
return NS;
}
// Check for conflicts between clobber list and input or output lists
SourceLocation ConstraintLoc = getClobberConflictLocation(
Exprs, constraints.data(), clobbers.data(), NumClobbers, NumLabels,
Context.getTargetInfo(), Context);
if (ConstraintLoc.isValid())
targetDiag(ConstraintLoc, diag::error_inoutput_conflict_with_clobber);
// Check for duplicate asm operand name between input, output and label lists.
typedef std::pair<StringRef , Expr *> NamedOperand;
SmallVector<NamedOperand, 4> NamedOperandList;
for (unsigned i = 0, e = NumOutputs + NumInputs + NumLabels; i != e; ++i)
if (Names[i])
NamedOperandList.emplace_back(
std::make_pair(Names[i]->getName(), Exprs[i]));
// Sort NamedOperandList.
llvm::stable_sort(NamedOperandList, llvm::less_first());
// Find adjacent duplicate operand.
SmallVector<NamedOperand, 4>::iterator Found =
std::adjacent_find(begin(NamedOperandList), end(NamedOperandList),
[](const NamedOperand &LHS, const NamedOperand &RHS) {
return LHS.first == RHS.first;
});
if (Found != NamedOperandList.end()) {
Diag((Found + 1)->second->getBeginLoc(),
diag::error_duplicate_asm_operand_name)
<< (Found + 1)->first;
Diag(Found->second->getBeginLoc(), diag::note_duplicate_asm_operand_name)
<< Found->first;
return StmtError();
}
if (NS->isAsmGoto())
setFunctionHasBranchIntoScope();
CleanupVarDeclMarking();
DiscardCleanupsInEvaluationContext();
return NS;
}
void Sema::FillInlineAsmIdentifierInfo(Expr *Res,
llvm::InlineAsmIdentifierInfo &Info) {
QualType T = Res->getType();
Expr::EvalResult Eval;
if (T->isFunctionType() || T->isDependentType())
return Info.setLabel(Res);
if (Res->isPRValue()) {
bool IsEnum = isa<clang::EnumType>(T);
if (DeclRefExpr *DRE = dyn_cast<clang::DeclRefExpr>(Res))
if (DRE->getDecl()->getKind() == Decl::EnumConstant)
IsEnum = true;
if (IsEnum && Res->EvaluateAsRValue(Eval, Context))
return Info.setEnum(Eval.Val.getInt().getSExtValue());
return Info.setLabel(Res);
}
unsigned Size = Context.getTypeSizeInChars(T).getQuantity();
unsigned Type = Size;
if (const auto *ATy = Context.getAsArrayType(T))
Type = Context.getTypeSizeInChars(ATy->getElementType()).getQuantity();
bool IsGlobalLV = false;
if (Res->EvaluateAsLValue(Eval, Context))
IsGlobalLV = Eval.isGlobalLValue();
Info.setVar(Res, IsGlobalLV, Size, Type);
}
ExprResult Sema::LookupInlineAsmIdentifier(CXXScopeSpec &SS,
SourceLocation TemplateKWLoc,
UnqualifiedId &Id,
bool IsUnevaluatedContext) {
if (IsUnevaluatedContext)
PushExpressionEvaluationContext(
ExpressionEvaluationContext::UnevaluatedAbstract,
ReuseLambdaContextDecl);
ExprResult Result = ActOnIdExpression(getCurScope(), SS, TemplateKWLoc, Id,
/*trailing lparen*/ false,
/*is & operand*/ false,
/*CorrectionCandidateCallback=*/nullptr,
/*IsInlineAsmIdentifier=*/ true);
if (IsUnevaluatedContext)
PopExpressionEvaluationContext();
if (!Result.isUsable()) return Result;
Result = CheckPlaceholderExpr(Result.get());
if (!Result.isUsable()) return Result;
// Referring to parameters is not allowed in naked functions.
if (CheckNakedParmReference(Result.get(), *this))
return ExprError();
QualType T = Result.get()->getType();
if (T->isDependentType()) {
return Result;
}
// Any sort of function type is fine.
if (T->isFunctionType()) {
return Result;
}
// Otherwise, it needs to be a complete type.
if (RequireCompleteExprType(Result.get(), diag::err_asm_incomplete_type)) {
return ExprError();
}
return Result;
}
bool Sema::LookupInlineAsmField(StringRef Base, StringRef Member,
unsigned &Offset, SourceLocation AsmLoc) {
Offset = 0;
SmallVector<StringRef, 2> Members;
Member.split(Members, ".");
NamedDecl *FoundDecl = nullptr;
// MS InlineAsm uses 'this' as a base
if (getLangOpts().CPlusPlus && Base == "this") {
if (const Type *PT = getCurrentThisType().getTypePtrOrNull())
FoundDecl = PT->getPointeeType()->getAsTagDecl();
} else {
LookupResult BaseResult(*this, &Context.Idents.get(Base), SourceLocation(),
LookupOrdinaryName);
if (LookupName(BaseResult, getCurScope()) && BaseResult.isSingleResult())
FoundDecl = BaseResult.getFoundDecl();
}
if (!FoundDecl)
return true;
for (StringRef NextMember : Members) {
const RecordType *RT = nullptr;
if (VarDecl *VD = dyn_cast<VarDecl>(FoundDecl))
RT = VD->getType()->getAs<RecordType>();
else if (TypedefNameDecl *TD = dyn_cast<TypedefNameDecl>(FoundDecl)) {
MarkAnyDeclReferenced(TD->getLocation(), TD, /*OdrUse=*/false);
// MS InlineAsm often uses struct pointer aliases as a base
QualType QT = TD->getUnderlyingType();
if (const auto *PT = QT->getAs<PointerType>())
QT = PT->getPointeeType();
RT = QT->getAs<RecordType>();
} else if (TypeDecl *TD = dyn_cast<TypeDecl>(FoundDecl))
RT = Context.getTypeDeclType(TD)->getAs<RecordType>();
else if (FieldDecl *TD = dyn_cast<FieldDecl>(FoundDecl))
RT = TD->getType()->getAs<RecordType>();
if (!RT)
return true;
if (RequireCompleteType(AsmLoc, QualType(RT, 0),
diag::err_asm_incomplete_type))
return true;
LookupResult FieldResult(*this, &Context.Idents.get(NextMember),
SourceLocation(), LookupMemberName);
RecordDecl *RD = RT->getOriginalDecl()->getDefinitionOrSelf();
if (!LookupQualifiedName(FieldResult, RD))
return true;
if (!FieldResult.isSingleResult())
return true;
FoundDecl = FieldResult.getFoundDecl();
// FIXME: Handle IndirectFieldDecl?
FieldDecl *FD = dyn_cast<FieldDecl>(FoundDecl);
if (!FD)
return true;
const ASTRecordLayout &RL = Context.getASTRecordLayout(RD);
unsigned i = FD->getFieldIndex();
CharUnits Result = Context.toCharUnitsFromBits(RL.getFieldOffset(i));
Offset += (unsigned)Result.getQuantity();
}
return false;
}
ExprResult
Sema::LookupInlineAsmVarDeclField(Expr *E, StringRef Member,
SourceLocation AsmLoc) {
QualType T = E->getType();
if (T->isDependentType()) {
DeclarationNameInfo NameInfo;
NameInfo.setLoc(AsmLoc);
NameInfo.setName(&Context.Idents.get(Member));
return CXXDependentScopeMemberExpr::Create(
Context, E, T, /*IsArrow=*/false, AsmLoc, NestedNameSpecifierLoc(),
SourceLocation(),
/*FirstQualifierFoundInScope=*/nullptr, NameInfo, /*TemplateArgs=*/nullptr);
}
const RecordType *RT = T->getAs<RecordType>();
// FIXME: Diagnose this as field access into a scalar type.
if (!RT)
return ExprResult();
LookupResult FieldResult(*this, &Context.Idents.get(Member), AsmLoc,
LookupMemberName);
if (!LookupQualifiedName(FieldResult,
RT->getOriginalDecl()->getDefinitionOrSelf()))
return ExprResult();
// Only normal and indirect field results will work.
ValueDecl *FD = dyn_cast<FieldDecl>(FieldResult.getFoundDecl());
if (!FD)
FD = dyn_cast<IndirectFieldDecl>(FieldResult.getFoundDecl());
if (!FD)
return ExprResult();
// Make an Expr to thread through OpDecl.
ExprResult Result = BuildMemberReferenceExpr(
E, E->getType(), AsmLoc, /*IsArrow=*/false, CXXScopeSpec(),
SourceLocation(), nullptr, FieldResult, nullptr, nullptr);
return Result;
}
StmtResult Sema::ActOnMSAsmStmt(SourceLocation AsmLoc, SourceLocation LBraceLoc,
ArrayRef<Token> AsmToks,
StringRef AsmString,
unsigned NumOutputs, unsigned NumInputs,
ArrayRef<StringRef> Constraints,
ArrayRef<StringRef> Clobbers,
ArrayRef<Expr*> Exprs,
SourceLocation EndLoc) {
bool IsSimple = (NumOutputs != 0 || NumInputs != 0);
setFunctionHasBranchProtectedScope();
bool InvalidOperand = false;
for (uint64_t I = 0; I < NumOutputs + NumInputs; ++I) {
Expr *E = Exprs[I];
if (E->getType()->isBitIntType()) {
InvalidOperand = true;
Diag(E->getBeginLoc(), diag::err_asm_invalid_type)
<< E->getType() << (I < NumOutputs)
<< E->getSourceRange();
} else if (E->refersToBitField()) {
InvalidOperand = true;
FieldDecl *BitField = E->getSourceBitField();
Diag(E->getBeginLoc(), diag::err_ms_asm_bitfield_unsupported)
<< E->getSourceRange();
Diag(BitField->getLocation(), diag::note_bitfield_decl);
}
}
if (InvalidOperand)
return StmtError();
MSAsmStmt *NS =
new (Context) MSAsmStmt(Context, AsmLoc, LBraceLoc, IsSimple,
/*IsVolatile*/ true, AsmToks, NumOutputs, NumInputs,
Constraints, Exprs, AsmString,
Clobbers, EndLoc);
return NS;
}
LabelDecl *Sema::GetOrCreateMSAsmLabel(StringRef ExternalLabelName,
SourceLocation Location,
bool AlwaysCreate) {
LabelDecl* Label = LookupOrCreateLabel(PP.getIdentifierInfo(ExternalLabelName),
Location);
if (Label->isMSAsmLabel()) {
// If we have previously created this label implicitly, mark it as used.
Label->markUsed(Context);
} else {
// Otherwise, insert it, but only resolve it if we have seen the label itself.
std::string InternalName;
llvm::raw_string_ostream OS(InternalName);
// Create an internal name for the label. The name should not be a valid
// mangled name, and should be unique. We use a dot to make the name an
// invalid mangled name. We use LLVM's inline asm ${:uid} escape so that a
// unique label is generated each time this blob is emitted, even after
// inlining or LTO.
OS << "__MSASMLABEL_.${:uid}__";
for (char C : ExternalLabelName) {
OS << C;
// We escape '$' in asm strings by replacing it with "$$"
if (C == '$')
OS << '$';
}
Label->setMSAsmLabel(OS.str());
}
if (AlwaysCreate) {
// The label might have been created implicitly from a previously encountered
// goto statement. So, for both newly created and looked up labels, we mark
// them as resolved.
Label->setMSAsmLabelResolved();
}
// Adjust their location for being able to generate accurate diagnostics.
Label->setLocation(Location);
return Label;
}
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