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//===--- SemaAttr.cpp - Semantic Analysis for Attributes ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements semantic analysis for non-trivial attributes and
// pragmas.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/Attr.h"
#include "clang/AST/Expr.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Sema/Lookup.h"
using namespace clang;
//===----------------------------------------------------------------------===//
// Pragma 'pack' and 'options align'
//===----------------------------------------------------------------------===//
Sema::PragmaStackSentinelRAII::PragmaStackSentinelRAII(Sema &S,
StringRef SlotLabel,
bool ShouldAct)
: S(S), SlotLabel(SlotLabel), ShouldAct(ShouldAct) {
if (ShouldAct) {
S.VtorDispStack.SentinelAction(PSK_Push, SlotLabel);
S.DataSegStack.SentinelAction(PSK_Push, SlotLabel);
S.BSSSegStack.SentinelAction(PSK_Push, SlotLabel);
S.ConstSegStack.SentinelAction(PSK_Push, SlotLabel);
S.CodeSegStack.SentinelAction(PSK_Push, SlotLabel);
}
}
Sema::PragmaStackSentinelRAII::~PragmaStackSentinelRAII() {
if (ShouldAct) {
S.VtorDispStack.SentinelAction(PSK_Pop, SlotLabel);
S.DataSegStack.SentinelAction(PSK_Pop, SlotLabel);
S.BSSSegStack.SentinelAction(PSK_Pop, SlotLabel);
S.ConstSegStack.SentinelAction(PSK_Pop, SlotLabel);
S.CodeSegStack.SentinelAction(PSK_Pop, SlotLabel);
}
}
void Sema::AddAlignmentAttributesForRecord(RecordDecl *RD) {
// If there is no pack value, we don't need any attributes.
if (!PackStack.CurrentValue)
return;
// Otherwise, check to see if we need a max field alignment attribute.
if (unsigned Alignment = PackStack.CurrentValue) {
if (Alignment == Sema::kMac68kAlignmentSentinel)
RD->addAttr(AlignMac68kAttr::CreateImplicit(Context));
else
RD->addAttr(MaxFieldAlignmentAttr::CreateImplicit(Context,
Alignment * 8));
}
}
void Sema::AddMsStructLayoutForRecord(RecordDecl *RD) {
if (MSStructPragmaOn)
RD->addAttr(MSStructAttr::CreateImplicit(Context));
// FIXME: We should merge AddAlignmentAttributesForRecord with
// AddMsStructLayoutForRecord into AddPragmaAttributesForRecord, which takes
// all active pragmas and applies them as attributes to class definitions.
if (VtorDispStack.CurrentValue != getLangOpts().VtorDispMode)
RD->addAttr(
MSVtorDispAttr::CreateImplicit(Context, VtorDispStack.CurrentValue));
}
void Sema::ActOnPragmaOptionsAlign(PragmaOptionsAlignKind Kind,
SourceLocation PragmaLoc) {
PragmaMsStackAction Action = Sema::PSK_Reset;
unsigned Alignment = 0;
switch (Kind) {
// For all targets we support native and natural are the same.
//
// FIXME: This is not true on Darwin/PPC.
case POAK_Native:
case POAK_Power:
case POAK_Natural:
Action = Sema::PSK_Push_Set;
Alignment = 0;
break;
// Note that '#pragma options align=packed' is not equivalent to attribute
// packed, it has a different precedence relative to attribute aligned.
case POAK_Packed:
Action = Sema::PSK_Push_Set;
Alignment = 1;
break;
case POAK_Mac68k:
// Check if the target supports this.
if (!this->Context.getTargetInfo().hasAlignMac68kSupport()) {
Diag(PragmaLoc, diag::err_pragma_options_align_mac68k_target_unsupported);
return;
}
Action = Sema::PSK_Push_Set;
Alignment = Sema::kMac68kAlignmentSentinel;
break;
case POAK_Reset:
// Reset just pops the top of the stack, or resets the current alignment to
// default.
Action = Sema::PSK_Pop;
if (PackStack.Stack.empty()) {
if (PackStack.CurrentValue) {
Action = Sema::PSK_Reset;
} else {
Diag(PragmaLoc, diag::warn_pragma_options_align_reset_failed)
<< "stack empty";
return;
}
}
break;
}
PackStack.Act(PragmaLoc, Action, StringRef(), Alignment);
}
void Sema::ActOnPragmaPack(SourceLocation PragmaLoc, PragmaMsStackAction Action,
StringRef SlotLabel, Expr *alignment) {
Expr *Alignment = static_cast<Expr *>(alignment);
// If specified then alignment must be a "small" power of two.
unsigned AlignmentVal = 0;
if (Alignment) {
llvm::APSInt Val;
// pack(0) is like pack(), which just works out since that is what
// we use 0 for in PackAttr.
if (Alignment->isTypeDependent() ||
Alignment->isValueDependent() ||
!Alignment->isIntegerConstantExpr(Val, Context) ||
!(Val == 0 || Val.isPowerOf2()) ||
Val.getZExtValue() > 16) {
Diag(PragmaLoc, diag::warn_pragma_pack_invalid_alignment);
return; // Ignore
}
AlignmentVal = (unsigned) Val.getZExtValue();
}
if (Action == Sema::PSK_Show) {
// Show the current alignment, making sure to show the right value
// for the default.
// FIXME: This should come from the target.
AlignmentVal = PackStack.CurrentValue;
if (AlignmentVal == 0)
AlignmentVal = 8;
if (AlignmentVal == Sema::kMac68kAlignmentSentinel)
Diag(PragmaLoc, diag::warn_pragma_pack_show) << "mac68k";
else
Diag(PragmaLoc, diag::warn_pragma_pack_show) << AlignmentVal;
}
// MSDN, C/C++ Preprocessor Reference > Pragma Directives > pack:
// "#pragma pack(pop, identifier, n) is undefined"
if (Action & Sema::PSK_Pop) {
if (Alignment && !SlotLabel.empty())
Diag(PragmaLoc, diag::warn_pragma_pack_pop_identifer_and_alignment);
if (PackStack.Stack.empty())
Diag(PragmaLoc, diag::warn_pragma_pop_failed) << "pack" << "stack empty";
}
PackStack.Act(PragmaLoc, Action, SlotLabel, AlignmentVal);
}
void Sema::ActOnPragmaMSStruct(PragmaMSStructKind Kind) {
MSStructPragmaOn = (Kind == PMSST_ON);
}
void Sema::ActOnPragmaMSComment(SourceLocation CommentLoc,
PragmaMSCommentKind Kind, StringRef Arg) {
auto *PCD = PragmaCommentDecl::Create(
Context, Context.getTranslationUnitDecl(), CommentLoc, Kind, Arg);
Context.getTranslationUnitDecl()->addDecl(PCD);
Consumer.HandleTopLevelDecl(DeclGroupRef(PCD));
}
void Sema::ActOnPragmaDetectMismatch(SourceLocation Loc, StringRef Name,
StringRef Value) {
auto *PDMD = PragmaDetectMismatchDecl::Create(
Context, Context.getTranslationUnitDecl(), Loc, Name, Value);
Context.getTranslationUnitDecl()->addDecl(PDMD);
Consumer.HandleTopLevelDecl(DeclGroupRef(PDMD));
}
void Sema::ActOnPragmaMSPointersToMembers(
LangOptions::PragmaMSPointersToMembersKind RepresentationMethod,
SourceLocation PragmaLoc) {
MSPointerToMemberRepresentationMethod = RepresentationMethod;
ImplicitMSInheritanceAttrLoc = PragmaLoc;
}
void Sema::ActOnPragmaMSVtorDisp(PragmaMsStackAction Action,
SourceLocation PragmaLoc,
MSVtorDispAttr::Mode Mode) {
if (Action & PSK_Pop && VtorDispStack.Stack.empty())
Diag(PragmaLoc, diag::warn_pragma_pop_failed) << "vtordisp"
<< "stack empty";
VtorDispStack.Act(PragmaLoc, Action, StringRef(), Mode);
}
template<typename ValueType>
void Sema::PragmaStack<ValueType>::Act(SourceLocation PragmaLocation,
PragmaMsStackAction Action,
llvm::StringRef StackSlotLabel,
ValueType Value) {
if (Action == PSK_Reset) {
CurrentValue = DefaultValue;
return;
}
if (Action & PSK_Push)
Stack.push_back(Slot(StackSlotLabel, CurrentValue, CurrentPragmaLocation));
else if (Action & PSK_Pop) {
if (!StackSlotLabel.empty()) {
// If we've got a label, try to find it and jump there.
auto I = llvm::find_if(llvm::reverse(Stack), [&](const Slot &x) {
return x.StackSlotLabel == StackSlotLabel;
});
// If we found the label so pop from there.
if (I != Stack.rend()) {
CurrentValue = I->Value;
CurrentPragmaLocation = I->PragmaLocation;
Stack.erase(std::prev(I.base()), Stack.end());
}
} else if (!Stack.empty()) {
// We don't have a label, just pop the last entry.
CurrentValue = Stack.back().Value;
CurrentPragmaLocation = Stack.back().PragmaLocation;
Stack.pop_back();
}
}
if (Action & PSK_Set) {
CurrentValue = Value;
CurrentPragmaLocation = PragmaLocation;
}
}
bool Sema::UnifySection(StringRef SectionName,
int SectionFlags,
DeclaratorDecl *Decl) {
auto Section = Context.SectionInfos.find(SectionName);
if (Section == Context.SectionInfos.end()) {
Context.SectionInfos[SectionName] =
ASTContext::SectionInfo(Decl, SourceLocation(), SectionFlags);
return false;
}
// A pre-declared section takes precedence w/o diagnostic.
if (Section->second.SectionFlags == SectionFlags ||
!(Section->second.SectionFlags & ASTContext::PSF_Implicit))
return false;
auto OtherDecl = Section->second.Decl;
Diag(Decl->getLocation(), diag::err_section_conflict)
<< Decl << OtherDecl;
Diag(OtherDecl->getLocation(), diag::note_declared_at)
<< OtherDecl->getName();
if (auto A = Decl->getAttr<SectionAttr>())
if (A->isImplicit())
Diag(A->getLocation(), diag::note_pragma_entered_here);
if (auto A = OtherDecl->getAttr<SectionAttr>())
if (A->isImplicit())
Diag(A->getLocation(), diag::note_pragma_entered_here);
return true;
}
bool Sema::UnifySection(StringRef SectionName,
int SectionFlags,
SourceLocation PragmaSectionLocation) {
auto Section = Context.SectionInfos.find(SectionName);
if (Section != Context.SectionInfos.end()) {
if (Section->second.SectionFlags == SectionFlags)
return false;
if (!(Section->second.SectionFlags & ASTContext::PSF_Implicit)) {
Diag(PragmaSectionLocation, diag::err_section_conflict)
<< "this" << "a prior #pragma section";
Diag(Section->second.PragmaSectionLocation,
diag::note_pragma_entered_here);
return true;
}
}
Context.SectionInfos[SectionName] =
ASTContext::SectionInfo(nullptr, PragmaSectionLocation, SectionFlags);
return false;
}
/// \brief Called on well formed \#pragma bss_seg().
void Sema::ActOnPragmaMSSeg(SourceLocation PragmaLocation,
PragmaMsStackAction Action,
llvm::StringRef StackSlotLabel,
StringLiteral *SegmentName,
llvm::StringRef PragmaName) {
PragmaStack<StringLiteral *> *Stack =
llvm::StringSwitch<PragmaStack<StringLiteral *> *>(PragmaName)
.Case("data_seg", &DataSegStack)
.Case("bss_seg", &BSSSegStack)
.Case("const_seg", &ConstSegStack)
.Case("code_seg", &CodeSegStack);
if (Action & PSK_Pop && Stack->Stack.empty())
Diag(PragmaLocation, diag::warn_pragma_pop_failed) << PragmaName
<< "stack empty";
if (SegmentName &&
!checkSectionName(SegmentName->getLocStart(), SegmentName->getString()))
return;
Stack->Act(PragmaLocation, Action, StackSlotLabel, SegmentName);
}
/// \brief Called on well formed \#pragma bss_seg().
void Sema::ActOnPragmaMSSection(SourceLocation PragmaLocation,
int SectionFlags, StringLiteral *SegmentName) {
UnifySection(SegmentName->getString(), SectionFlags, PragmaLocation);
}
void Sema::ActOnPragmaMSInitSeg(SourceLocation PragmaLocation,
StringLiteral *SegmentName) {
// There's no stack to maintain, so we just have a current section. When we
// see the default section, reset our current section back to null so we stop
// tacking on unnecessary attributes.
CurInitSeg = SegmentName->getString() == ".CRT$XCU" ? nullptr : SegmentName;
CurInitSegLoc = PragmaLocation;
}
void Sema::ActOnPragmaUnused(const Token &IdTok, Scope *curScope,
SourceLocation PragmaLoc) {
IdentifierInfo *Name = IdTok.getIdentifierInfo();
LookupResult Lookup(*this, Name, IdTok.getLocation(), LookupOrdinaryName);
LookupParsedName(Lookup, curScope, nullptr, true);
if (Lookup.empty()) {
Diag(PragmaLoc, diag::warn_pragma_unused_undeclared_var)
<< Name << SourceRange(IdTok.getLocation());
return;
}
VarDecl *VD = Lookup.getAsSingle<VarDecl>();
if (!VD) {
Diag(PragmaLoc, diag::warn_pragma_unused_expected_var_arg)
<< Name << SourceRange(IdTok.getLocation());
return;
}
// Warn if this was used before being marked unused.
if (VD->isUsed())
Diag(PragmaLoc, diag::warn_used_but_marked_unused) << Name;
VD->addAttr(UnusedAttr::CreateImplicit(Context, UnusedAttr::GNU_unused,
IdTok.getLocation()));
}
void Sema::AddCFAuditedAttribute(Decl *D) {
SourceLocation Loc = PP.getPragmaARCCFCodeAuditedLoc();
if (!Loc.isValid()) return;
// Don't add a redundant or conflicting attribute.
if (D->hasAttr<CFAuditedTransferAttr>() ||
D->hasAttr<CFUnknownTransferAttr>())
return;
D->addAttr(CFAuditedTransferAttr::CreateImplicit(Context, Loc));
}
void Sema::ActOnPragmaOptimize(bool On, SourceLocation PragmaLoc) {
if(On)
OptimizeOffPragmaLocation = SourceLocation();
else
OptimizeOffPragmaLocation = PragmaLoc;
}
void Sema::AddRangeBasedOptnone(FunctionDecl *FD) {
// In the future, check other pragmas if they're implemented (e.g. pragma
// optimize 0 will probably map to this functionality too).
if(OptimizeOffPragmaLocation.isValid())
AddOptnoneAttributeIfNoConflicts(FD, OptimizeOffPragmaLocation);
}
void Sema::AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD,
SourceLocation Loc) {
// Don't add a conflicting attribute. No diagnostic is needed.
if (FD->hasAttr<MinSizeAttr>() || FD->hasAttr<AlwaysInlineAttr>())
return;
// Add attributes only if required. Optnone requires noinline as well, but if
// either is already present then don't bother adding them.
if (!FD->hasAttr<OptimizeNoneAttr>())
FD->addAttr(OptimizeNoneAttr::CreateImplicit(Context, Loc));
if (!FD->hasAttr<NoInlineAttr>())
FD->addAttr(NoInlineAttr::CreateImplicit(Context, Loc));
}
typedef std::vector<std::pair<unsigned, SourceLocation> > VisStack;
enum : unsigned { NoVisibility = ~0U };
void Sema::AddPushedVisibilityAttribute(Decl *D) {
if (!VisContext)
return;
NamedDecl *ND = dyn_cast<NamedDecl>(D);
if (ND && ND->getExplicitVisibility(NamedDecl::VisibilityForValue))
return;
VisStack *Stack = static_cast<VisStack*>(VisContext);
unsigned rawType = Stack->back().first;
if (rawType == NoVisibility) return;
VisibilityAttr::VisibilityType type
= (VisibilityAttr::VisibilityType) rawType;
SourceLocation loc = Stack->back().second;
D->addAttr(VisibilityAttr::CreateImplicit(Context, type, loc));
}
/// FreeVisContext - Deallocate and null out VisContext.
void Sema::FreeVisContext() {
delete static_cast<VisStack*>(VisContext);
VisContext = nullptr;
}
static void PushPragmaVisibility(Sema &S, unsigned type, SourceLocation loc) {
// Put visibility on stack.
if (!S.VisContext)
S.VisContext = new VisStack;
VisStack *Stack = static_cast<VisStack*>(S.VisContext);
Stack->push_back(std::make_pair(type, loc));
}
void Sema::ActOnPragmaVisibility(const IdentifierInfo* VisType,
SourceLocation PragmaLoc) {
if (VisType) {
// Compute visibility to use.
VisibilityAttr::VisibilityType T;
if (!VisibilityAttr::ConvertStrToVisibilityType(VisType->getName(), T)) {
Diag(PragmaLoc, diag::warn_attribute_unknown_visibility) << VisType;
return;
}
PushPragmaVisibility(*this, T, PragmaLoc);
} else {
PopPragmaVisibility(false, PragmaLoc);
}
}
void Sema::ActOnPragmaFPContract(tok::OnOffSwitch OOS) {
switch (OOS) {
case tok::OOS_ON:
FPFeatures.fp_contract = 1;
break;
case tok::OOS_OFF:
FPFeatures.fp_contract = 0;
break;
case tok::OOS_DEFAULT:
FPFeatures.fp_contract = getLangOpts().DefaultFPContract;
break;
}
}
void Sema::PushNamespaceVisibilityAttr(const VisibilityAttr *Attr,
SourceLocation Loc) {
// Visibility calculations will consider the namespace's visibility.
// Here we just want to note that we're in a visibility context
// which overrides any enclosing #pragma context, but doesn't itself
// contribute visibility.
PushPragmaVisibility(*this, NoVisibility, Loc);
}
void Sema::PopPragmaVisibility(bool IsNamespaceEnd, SourceLocation EndLoc) {
if (!VisContext) {
Diag(EndLoc, diag::err_pragma_pop_visibility_mismatch);
return;
}
// Pop visibility from stack
VisStack *Stack = static_cast<VisStack*>(VisContext);
const std::pair<unsigned, SourceLocation> *Back = &Stack->back();
bool StartsWithPragma = Back->first != NoVisibility;
if (StartsWithPragma && IsNamespaceEnd) {
Diag(Back->second, diag::err_pragma_push_visibility_mismatch);
Diag(EndLoc, diag::note_surrounding_namespace_ends_here);
// For better error recovery, eat all pushes inside the namespace.
do {
Stack->pop_back();
Back = &Stack->back();
StartsWithPragma = Back->first != NoVisibility;
} while (StartsWithPragma);
} else if (!StartsWithPragma && !IsNamespaceEnd) {
Diag(EndLoc, diag::err_pragma_pop_visibility_mismatch);
Diag(Back->second, diag::note_surrounding_namespace_starts_here);
return;
}
Stack->pop_back();
// To simplify the implementation, never keep around an empty stack.
if (Stack->empty())
FreeVisContext();
}