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//===--- SemaStmtAttr.cpp - Statement Attribute Handling ------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements stmt-related attribute processing.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/LoopHint.h"
#include "clang/Sema/ScopeInfo.h"
#include "llvm/ADT/StringExtras.h"
using namespace clang;
using namespace sema;
static Attr *handleFallThroughAttr(Sema &S, Stmt *St, const AttributeList &A,
SourceRange Range) {
if (!isa<NullStmt>(St)) {
S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_wrong_target)
<< St->getLocStart();
if (isa<SwitchCase>(St)) {
SourceLocation L = S.getLocForEndOfToken(Range.getEnd());
S.Diag(L, diag::note_fallthrough_insert_semi_fixit)
<< FixItHint::CreateInsertion(L, ";");
}
return nullptr;
}
if (S.getCurFunction()->SwitchStack.empty()) {
S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_outside_switch);
return nullptr;
}
return ::new (S.Context) FallThroughAttr(A.getRange(), S.Context,
A.getAttributeSpellingListIndex());
}
static Attr *handleLoopHintAttr(Sema &S, Stmt *St, const AttributeList &A,
SourceRange) {
IdentifierLoc *PragmaNameLoc = A.getArgAsIdent(0);
IdentifierLoc *OptionLoc = A.getArgAsIdent(1);
IdentifierInfo *OptionInfo = OptionLoc->Ident;
IdentifierLoc *ValueLoc = A.getArgAsIdent(2);
IdentifierInfo *ValueInfo = ValueLoc ? ValueLoc->Ident : nullptr;
Expr *ValueExpr = A.getArgAsExpr(3);
assert(OptionInfo && "Attribute must have valid option info.");
if (St->getStmtClass() != Stmt::DoStmtClass &&
St->getStmtClass() != Stmt::ForStmtClass &&
St->getStmtClass() != Stmt::CXXForRangeStmtClass &&
St->getStmtClass() != Stmt::WhileStmtClass) {
const char *Pragma =
llvm::StringSwitch<const char *>(PragmaNameLoc->Ident->getName())
.Case("unroll", "#pragma unroll")
.Case("nounroll", "#pragma nounroll")
.Default("#pragma clang loop");
S.Diag(St->getLocStart(), diag::err_pragma_loop_precedes_nonloop) << Pragma;
return nullptr;
}
LoopHintAttr::OptionType Option;
LoopHintAttr::Spelling Spelling;
if (PragmaNameLoc->Ident->getName() == "unroll") {
Option = ValueLoc ? LoopHintAttr::UnrollCount : LoopHintAttr::Unroll;
Spelling = LoopHintAttr::Pragma_unroll;
} else if (PragmaNameLoc->Ident->getName() == "nounroll") {
Option = LoopHintAttr::Unroll;
Spelling = LoopHintAttr::Pragma_nounroll;
} else {
Option = llvm::StringSwitch<LoopHintAttr::OptionType>(OptionInfo->getName())
.Case("vectorize", LoopHintAttr::Vectorize)
.Case("vectorize_width", LoopHintAttr::VectorizeWidth)
.Case("interleave", LoopHintAttr::Interleave)
.Case("interleave_count", LoopHintAttr::InterleaveCount)
.Case("unroll", LoopHintAttr::Unroll)
.Case("unroll_count", LoopHintAttr::UnrollCount)
.Default(LoopHintAttr::Vectorize);
Spelling = LoopHintAttr::Pragma_clang_loop;
}
int ValueInt;
if (Option == LoopHintAttr::Unroll &&
Spelling == LoopHintAttr::Pragma_unroll) {
ValueInt = 1;
} else if (Option == LoopHintAttr::Unroll &&
Spelling == LoopHintAttr::Pragma_nounroll) {
ValueInt = 0;
} else if (Option == LoopHintAttr::Vectorize ||
Option == LoopHintAttr::Interleave ||
Option == LoopHintAttr::Unroll) {
// Unrolling uses the keyword "full" rather than "enable" to indicate full
// unrolling.
const char *TrueKeyword =
Option == LoopHintAttr::Unroll ? "full" : "enable";
if (!ValueInfo) {
S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
<< TrueKeyword;
return nullptr;
}
if (ValueInfo->isStr("disable"))
ValueInt = 0;
else if (ValueInfo->getName() == TrueKeyword)
ValueInt = 1;
else {
S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_keyword)
<< TrueKeyword;
return nullptr;
}
} else if (Option == LoopHintAttr::VectorizeWidth ||
Option == LoopHintAttr::InterleaveCount ||
Option == LoopHintAttr::UnrollCount) {
// FIXME: We should support template parameters for the loop hint value.
// See bug report #19610.
llvm::APSInt ValueAPS;
if (!ValueExpr || !ValueExpr->isIntegerConstantExpr(ValueAPS, S.Context) ||
(ValueInt = ValueAPS.getSExtValue()) < 1) {
S.Diag(ValueLoc->Loc, diag::err_pragma_loop_invalid_value);
return nullptr;
}
} else
llvm_unreachable("Unknown loop hint option");
return LoopHintAttr::CreateImplicit(S.Context, Spelling, Option, ValueInt,
A.getRange());
}
static void CheckForIncompatibleAttributes(
Sema &S, const SmallVectorImpl<const Attr *> &Attrs) {
// There are 3 categories of loop hints attributes: vectorize, interleave, and
// unroll. Each comes in two variants: a boolean form and a numeric form. The
// boolean hints selectively enables/disables the transformation for the loop
// (for unroll, a nonzero value indicates full unrolling rather than enabling
// the transformation). The numeric hint provides an integer hint (for
// example, unroll count) to the transformer. The following array accumulates
// the hints encountered while iterating through the attributes to check for
// compatibility.
struct {
const LoopHintAttr *EnableAttr;
const LoopHintAttr *NumericAttr;
} HintAttrs[] = {{nullptr, nullptr}, {nullptr, nullptr}, {nullptr, nullptr}};
for (const auto *I : Attrs) {
const LoopHintAttr *LH = dyn_cast<LoopHintAttr>(I);
// Skip non loop hint attributes
if (!LH)
continue;
int Option = LH->getOption();
int Category;
enum { Vectorize, Interleave, Unroll };
switch (Option) {
case LoopHintAttr::Vectorize:
case LoopHintAttr::VectorizeWidth:
Category = Vectorize;
break;
case LoopHintAttr::Interleave:
case LoopHintAttr::InterleaveCount:
Category = Interleave;
break;
case LoopHintAttr::Unroll:
case LoopHintAttr::UnrollCount:
Category = Unroll;
break;
};
auto &CategoryState = HintAttrs[Category];
SourceLocation OptionLoc = LH->getRange().getBegin();
const LoopHintAttr *PrevAttr;
if (Option == LoopHintAttr::Vectorize ||
Option == LoopHintAttr::Interleave || Option == LoopHintAttr::Unroll) {
// Enable|disable hint. For example, vectorize(enable).
PrevAttr = CategoryState.EnableAttr;
CategoryState.EnableAttr = LH;
} else {
// Numeric hint. For example, vectorize_width(8).
PrevAttr = CategoryState.NumericAttr;
CategoryState.NumericAttr = LH;
}
if (PrevAttr)
// Cannot specify same type of attribute twice.
S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
<< /*Duplicate=*/true << PrevAttr->getDiagnosticName()
<< LH->getDiagnosticName();
if (CategoryState.EnableAttr && CategoryState.NumericAttr &&
(Category == Unroll || !CategoryState.EnableAttr->getValue())) {
// Disable hints are not compatible with numeric hints of the same
// category. As a special case, numeric unroll hints are also not
// compatible with "enable" form of the unroll pragma, unroll(full).
S.Diag(OptionLoc, diag::err_pragma_loop_compatibility)
<< /*Duplicate=*/false
<< CategoryState.EnableAttr->getDiagnosticName()
<< CategoryState.NumericAttr->getDiagnosticName();
}
}
}
static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const AttributeList &A,
SourceRange Range) {
switch (A.getKind()) {
case AttributeList::UnknownAttribute:
S.Diag(A.getLoc(), A.isDeclspecAttribute() ?
diag::warn_unhandled_ms_attribute_ignored :
diag::warn_unknown_attribute_ignored) << A.getName();
return nullptr;
case AttributeList::AT_FallThrough:
return handleFallThroughAttr(S, St, A, Range);
case AttributeList::AT_LoopHint:
return handleLoopHintAttr(S, St, A, Range);
default:
// if we're here, then we parsed a known attribute, but didn't recognize
// it as a statement attribute => it is declaration attribute
S.Diag(A.getRange().getBegin(), diag::err_attribute_invalid_on_stmt)
<< A.getName() << St->getLocStart();
return nullptr;
}
}
StmtResult Sema::ProcessStmtAttributes(Stmt *S, AttributeList *AttrList,
SourceRange Range) {
SmallVector<const Attr*, 8> Attrs;
for (const AttributeList* l = AttrList; l; l = l->getNext()) {
if (Attr *a = ProcessStmtAttribute(*this, S, *l, Range))
Attrs.push_back(a);
}
CheckForIncompatibleAttributes(*this, Attrs);
if (Attrs.empty())
return S;
return ActOnAttributedStmt(Range.getBegin(), Attrs, S);
}
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