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llvm / clang / refs/heads/release_32 / . / lib / Sema / AnalysisBasedWarnings.cpp
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//=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines analysis_warnings::[Policy,Executor].
// Together they are used by Sema to issue warnings based on inexpensive
// static analysis algorithms in libAnalysis.
//
//===----------------------------------------------------------------------===//
#include "clang/Sema/AnalysisBasedWarnings.h"
#include "clang/Sema/SemaInternal.h"
#include "clang/Sema/ScopeInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/Lexer.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/ExprObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtObjC.h"
#include "clang/AST/StmtCXX.h"
#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/ParentMap.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/Analyses/ReachableCode.h"
#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
#include "clang/Analysis/Analyses/ThreadSafety.h"
#include "clang/Analysis/CFGStmtMap.h"
#include "clang/Analysis/Analyses/UninitializedValues.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableMap.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include <algorithm>
#include <iterator>
#include <vector>
#include <deque>
using namespace clang;
//===----------------------------------------------------------------------===//
// Unreachable code analysis.
//===----------------------------------------------------------------------===//
namespace {
class UnreachableCodeHandler : public reachable_code::Callback {
Sema &S;
public:
UnreachableCodeHandler(Sema &s) : S(s) {}
void HandleUnreachable(SourceLocation L, SourceRange R1, SourceRange R2) {
S.Diag(L, diag::warn_unreachable) << R1 << R2;
}
};
}
/// CheckUnreachable - Check for unreachable code.
static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC) {
UnreachableCodeHandler UC(S);
reachable_code::FindUnreachableCode(AC, UC);
}
//===----------------------------------------------------------------------===//
// Check for missing return value.
//===----------------------------------------------------------------------===//
enum ControlFlowKind {
UnknownFallThrough,
NeverFallThrough,
MaybeFallThrough,
AlwaysFallThrough,
NeverFallThroughOrReturn
};
/// CheckFallThrough - Check that we don't fall off the end of a
/// Statement that should return a value.
///
/// \returns AlwaysFallThrough iff we always fall off the end of the statement,
/// MaybeFallThrough iff we might or might not fall off the end,
/// NeverFallThroughOrReturn iff we never fall off the end of the statement or
/// return. We assume NeverFallThrough iff we never fall off the end of the
/// statement but we may return. We assume that functions not marked noreturn
/// will return.
static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
CFG *cfg = AC.getCFG();
if (cfg == 0) return UnknownFallThrough;
// The CFG leaves in dead things, and we don't want the dead code paths to
// confuse us, so we mark all live things first.
llvm::BitVector live(cfg->getNumBlockIDs());
unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
live);
bool AddEHEdges = AC.getAddEHEdges();
if (!AddEHEdges && count != cfg->getNumBlockIDs())
// When there are things remaining dead, and we didn't add EH edges
// from CallExprs to the catch clauses, we have to go back and
// mark them as live.
for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
CFGBlock &b = **I;
if (!live[b.getBlockID()]) {
if (b.pred_begin() == b.pred_end()) {
if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator()))
// When not adding EH edges from calls, catch clauses
// can otherwise seem dead. Avoid noting them as dead.
count += reachable_code::ScanReachableFromBlock(&b, live);
continue;
}
}
}
// Now we know what is live, we check the live precessors of the exit block
// and look for fall through paths, being careful to ignore normal returns,
// and exceptional paths.
bool HasLiveReturn = false;
bool HasFakeEdge = false;
bool HasPlainEdge = false;
bool HasAbnormalEdge = false;
// Ignore default cases that aren't likely to be reachable because all
// enums in a switch(X) have explicit case statements.
CFGBlock::FilterOptions FO;
FO.IgnoreDefaultsWithCoveredEnums = 1;
for (CFGBlock::filtered_pred_iterator
I = cfg->getExit().filtered_pred_start_end(FO); I.hasMore(); ++I) {
const CFGBlock& B = **I;
if (!live[B.getBlockID()])
continue;
// Skip blocks which contain an element marked as no-return. They don't
// represent actually viable edges into the exit block, so mark them as
// abnormal.
if (B.hasNoReturnElement()) {
HasAbnormalEdge = true;
continue;
}
// Destructors can appear after the 'return' in the CFG. This is
// normal. We need to look pass the destructors for the return
// statement (if it exists).
CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
for ( ; ri != re ; ++ri)
if (isa<CFGStmt>(*ri))
break;
// No more CFGElements in the block?
if (ri == re) {
if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
HasAbnormalEdge = true;
continue;
}
// A labeled empty statement, or the entry block...
HasPlainEdge = true;
continue;
}
CFGStmt CS = cast<CFGStmt>(*ri);
const Stmt *S = CS.getStmt();
if (isa<ReturnStmt>(S)) {
HasLiveReturn = true;
continue;
}
if (isa<ObjCAtThrowStmt>(S)) {
HasFakeEdge = true;
continue;
}
if (isa<CXXThrowExpr>(S)) {
HasFakeEdge = true;
continue;
}
if (isa<MSAsmStmt>(S)) {
// TODO: Verify this is correct.
HasFakeEdge = true;
HasLiveReturn = true;
continue;
}
if (isa<CXXTryStmt>(S)) {
HasAbnormalEdge = true;
continue;
}
if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
== B.succ_end()) {
HasAbnormalEdge = true;
continue;
}
HasPlainEdge = true;
}
if (!HasPlainEdge) {
if (HasLiveReturn)
return NeverFallThrough;
return NeverFallThroughOrReturn;
}
if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
return MaybeFallThrough;
// This says AlwaysFallThrough for calls to functions that are not marked
// noreturn, that don't return. If people would like this warning to be more
// accurate, such functions should be marked as noreturn.
return AlwaysFallThrough;
}
namespace {
struct CheckFallThroughDiagnostics {
unsigned diag_MaybeFallThrough_HasNoReturn;
unsigned diag_MaybeFallThrough_ReturnsNonVoid;
unsigned diag_AlwaysFallThrough_HasNoReturn;
unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
unsigned diag_NeverFallThroughOrReturn;
enum { Function, Block, Lambda } funMode;
SourceLocation FuncLoc;
static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
CheckFallThroughDiagnostics D;
D.FuncLoc = Func->getLocation();
D.diag_MaybeFallThrough_HasNoReturn =
diag::warn_falloff_noreturn_function;
D.diag_MaybeFallThrough_ReturnsNonVoid =
diag::warn_maybe_falloff_nonvoid_function;
D.diag_AlwaysFallThrough_HasNoReturn =
diag::warn_falloff_noreturn_function;
D.diag_AlwaysFallThrough_ReturnsNonVoid =
diag::warn_falloff_nonvoid_function;
// Don't suggest that virtual functions be marked "noreturn", since they
// might be overridden by non-noreturn functions.
bool isVirtualMethod = false;
if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
isVirtualMethod = Method->isVirtual();
// Don't suggest that template instantiations be marked "noreturn"
bool isTemplateInstantiation = false;
if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
isTemplateInstantiation = Function->isTemplateInstantiation();
if (!isVirtualMethod && !isTemplateInstantiation)
D.diag_NeverFallThroughOrReturn =
diag::warn_suggest_noreturn_function;
else
D.diag_NeverFallThroughOrReturn = 0;
D.funMode = Function;
return D;
}
static CheckFallThroughDiagnostics MakeForBlock() {
CheckFallThroughDiagnostics D;
D.diag_MaybeFallThrough_HasNoReturn =
diag::err_noreturn_block_has_return_expr;
D.diag_MaybeFallThrough_ReturnsNonVoid =
diag::err_maybe_falloff_nonvoid_block;
D.diag_AlwaysFallThrough_HasNoReturn =
diag::err_noreturn_block_has_return_expr;
D.diag_AlwaysFallThrough_ReturnsNonVoid =
diag::err_falloff_nonvoid_block;
D.diag_NeverFallThroughOrReturn =
diag::warn_suggest_noreturn_block;
D.funMode = Block;
return D;
}
static CheckFallThroughDiagnostics MakeForLambda() {
CheckFallThroughDiagnostics D;
D.diag_MaybeFallThrough_HasNoReturn =
diag::err_noreturn_lambda_has_return_expr;
D.diag_MaybeFallThrough_ReturnsNonVoid =
diag::warn_maybe_falloff_nonvoid_lambda;
D.diag_AlwaysFallThrough_HasNoReturn =
diag::err_noreturn_lambda_has_return_expr;
D.diag_AlwaysFallThrough_ReturnsNonVoid =
diag::warn_falloff_nonvoid_lambda;
D.diag_NeverFallThroughOrReturn = 0;
D.funMode = Lambda;
return D;
}
bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
bool HasNoReturn) const {
if (funMode == Function) {
return (ReturnsVoid ||
D.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function,
FuncLoc) == DiagnosticsEngine::Ignored)
&& (!HasNoReturn ||
D.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr,
FuncLoc) == DiagnosticsEngine::Ignored)
&& (!ReturnsVoid ||
D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
== DiagnosticsEngine::Ignored);
}
// For blocks / lambdas.
return ReturnsVoid && !HasNoReturn
&& ((funMode == Lambda) ||
D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
== DiagnosticsEngine::Ignored);
}
};
}
/// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a
/// function that should return a value. Check that we don't fall off the end
/// of a noreturn function. We assume that functions and blocks not marked
/// noreturn will return.
static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
const BlockExpr *blkExpr,
const CheckFallThroughDiagnostics& CD,
AnalysisDeclContext &AC) {
bool ReturnsVoid = false;
bool HasNoReturn = false;
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
ReturnsVoid = FD->getResultType()->isVoidType();
HasNoReturn = FD->hasAttr<NoReturnAttr>() ||
FD->getType()->getAs<FunctionType>()->getNoReturnAttr();
}
else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
ReturnsVoid = MD->getResultType()->isVoidType();
HasNoReturn = MD->hasAttr<NoReturnAttr>();
}
else if (isa<BlockDecl>(D)) {
QualType BlockTy = blkExpr->getType();
if (const FunctionType *FT =
BlockTy->getPointeeType()->getAs<FunctionType>()) {
if (FT->getResultType()->isVoidType())
ReturnsVoid = true;
if (FT->getNoReturnAttr())
HasNoReturn = true;
}
}
DiagnosticsEngine &Diags = S.getDiagnostics();
// Short circuit for compilation speed.
if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
return;
// FIXME: Function try block
if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
switch (CheckFallThrough(AC)) {
case UnknownFallThrough:
break;
case MaybeFallThrough:
if (HasNoReturn)
S.Diag(Compound->getRBracLoc(),
CD.diag_MaybeFallThrough_HasNoReturn);
else if (!ReturnsVoid)
S.Diag(Compound->getRBracLoc(),
CD.diag_MaybeFallThrough_ReturnsNonVoid);
break;
case AlwaysFallThrough:
if (HasNoReturn)
S.Diag(Compound->getRBracLoc(),
CD.diag_AlwaysFallThrough_HasNoReturn);
else if (!ReturnsVoid)
S.Diag(Compound->getRBracLoc(),
CD.diag_AlwaysFallThrough_ReturnsNonVoid);
break;
case NeverFallThroughOrReturn:
if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
<< 0 << FD;
} else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
<< 1 << MD;
} else {
S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn);
}
}
break;
case NeverFallThrough:
break;
}
}
}
//===----------------------------------------------------------------------===//
// -Wuninitialized
//===----------------------------------------------------------------------===//
namespace {
/// ContainsReference - A visitor class to search for references to
/// a particular declaration (the needle) within any evaluated component of an
/// expression (recursively).
class ContainsReference : public EvaluatedExprVisitor<ContainsReference> {
bool FoundReference;
const DeclRefExpr *Needle;
public:
ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
: EvaluatedExprVisitor<ContainsReference>(Context),
FoundReference(false), Needle(Needle) {}
void VisitExpr(Expr *E) {
// Stop evaluating if we already have a reference.
if (FoundReference)
return;
EvaluatedExprVisitor<ContainsReference>::VisitExpr(E);
}
void VisitDeclRefExpr(DeclRefExpr *E) {
if (E == Needle)
FoundReference = true;
else
EvaluatedExprVisitor<ContainsReference>::VisitDeclRefExpr(E);
}
bool doesContainReference() const { return FoundReference; }
};
}
static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
QualType VariableTy = VD->getType().getCanonicalType();
if (VariableTy->isBlockPointerType() &&
!VD->hasAttr<BlocksAttr>()) {
S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization) << VD->getDeclName()
<< FixItHint::CreateInsertion(VD->getLocation(), "__block ");
return true;
}
// Don't issue a fixit if there is already an initializer.
if (VD->getInit())
return false;
// Suggest possible initialization (if any).
std::string Init = S.getFixItZeroInitializerForType(VariableTy);
if (Init.empty())
return false;
// Don't suggest a fixit inside macros.
if (VD->getLocEnd().isMacroID())
return false;
SourceLocation Loc = S.PP.getLocForEndOfToken(VD->getLocEnd());
S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
<< FixItHint::CreateInsertion(Loc, Init);
return true;
}
/// Create a fixit to remove an if-like statement, on the assumption that its
/// condition is CondVal.
static void CreateIfFixit(Sema &S, const Stmt *If, const Stmt *Then,
const Stmt *Else, bool CondVal,
FixItHint &Fixit1, FixItHint &Fixit2) {
if (CondVal) {
// If condition is always true, remove all but the 'then'.
Fixit1 = FixItHint::CreateRemoval(
CharSourceRange::getCharRange(If->getLocStart(),
Then->getLocStart()));
if (Else) {
SourceLocation ElseKwLoc = Lexer::getLocForEndOfToken(
Then->getLocEnd(), 0, S.getSourceManager(), S.getLangOpts());
Fixit2 = FixItHint::CreateRemoval(
SourceRange(ElseKwLoc, Else->getLocEnd()));
}
} else {
// If condition is always false, remove all but the 'else'.
if (Else)
Fixit1 = FixItHint::CreateRemoval(
CharSourceRange::getCharRange(If->getLocStart(),
Else->getLocStart()));
else
Fixit1 = FixItHint::CreateRemoval(If->getSourceRange());
}
}
/// DiagUninitUse -- Helper function to produce a diagnostic for an
/// uninitialized use of a variable.
static void DiagUninitUse(Sema &S, const VarDecl *VD, const UninitUse &Use,
bool IsCapturedByBlock) {
bool Diagnosed = false;
// Diagnose each branch which leads to a sometimes-uninitialized use.
for (UninitUse::branch_iterator I = Use.branch_begin(), E = Use.branch_end();
I != E; ++I) {
assert(Use.getKind() == UninitUse::Sometimes);
const Expr *User = Use.getUser();
const Stmt *Term = I->Terminator;
// Information used when building the diagnostic.
unsigned DiagKind;
StringRef Str;
SourceRange Range;
// FixIts to suppress the diagnosic by removing the dead condition.
// For all binary terminators, branch 0 is taken if the condition is true,
// and branch 1 is taken if the condition is false.
int RemoveDiagKind = -1;
const char *FixitStr =
S.getLangOpts().CPlusPlus ? (I->Output ? "true" : "false")
: (I->Output ? "1" : "0");
FixItHint Fixit1, Fixit2;
switch (Term->getStmtClass()) {
default:
// Don't know how to report this. Just fall back to 'may be used
// uninitialized'. This happens for range-based for, which the user
// can't explicitly fix.
// FIXME: This also happens if the first use of a variable is always
// uninitialized, eg "for (int n; n < 10; ++n)". We should report that
// with the 'is uninitialized' diagnostic.
continue;
// "condition is true / condition is false".
case Stmt::IfStmtClass: {
const IfStmt *IS = cast<IfStmt>(Term);
DiagKind = 0;
Str = "if";
Range = IS->getCond()->getSourceRange();
RemoveDiagKind = 0;
CreateIfFixit(S, IS, IS->getThen(), IS->getElse(),
I->Output, Fixit1, Fixit2);
break;
}
case Stmt::ConditionalOperatorClass: {
const ConditionalOperator *CO = cast<ConditionalOperator>(Term);
DiagKind = 0;
Str = "?:";
Range = CO->getCond()->getSourceRange();
RemoveDiagKind = 0;
CreateIfFixit(S, CO, CO->getTrueExpr(), CO->getFalseExpr(),
I->Output, Fixit1, Fixit2);
break;
}
case Stmt::BinaryOperatorClass: {
const BinaryOperator *BO = cast<BinaryOperator>(Term);
if (!BO->isLogicalOp())
continue;
DiagKind = 0;
Str = BO->getOpcodeStr();
Range = BO->getLHS()->getSourceRange();
RemoveDiagKind = 0;
if ((BO->getOpcode() == BO_LAnd && I->Output) ||
(BO->getOpcode() == BO_LOr && !I->Output))
// true && y -> y, false || y -> y.
Fixit1 = FixItHint::CreateRemoval(SourceRange(BO->getLocStart(),
BO->getOperatorLoc()));
else
// false && y -> false, true || y -> true.
Fixit1 = FixItHint::CreateReplacement(BO->getSourceRange(), FixitStr);
break;
}
// "loop is entered / loop is exited".
case Stmt::WhileStmtClass:
DiagKind = 1;
Str = "while";
Range = cast<WhileStmt>(Term)->getCond()->getSourceRange();
RemoveDiagKind = 1;
Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
break;
case Stmt::ForStmtClass:
DiagKind = 1;
Str = "for";
Range = cast<ForStmt>(Term)->getCond()->getSourceRange();
RemoveDiagKind = 1;
if (I->Output)
Fixit1 = FixItHint::CreateRemoval(Range);
else
Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
break;
// "condition is true / loop is exited".
case Stmt::DoStmtClass:
DiagKind = 2;
Str = "do";
Range = cast<DoStmt>(Term)->getCond()->getSourceRange();
RemoveDiagKind = 1;
Fixit1 = FixItHint::CreateReplacement(Range, FixitStr);
break;
// "switch case is taken".
case Stmt::CaseStmtClass:
DiagKind = 3;
Str = "case";
Range = cast<CaseStmt>(Term)->getLHS()->getSourceRange();
break;
case Stmt::DefaultStmtClass:
DiagKind = 3;
Str = "default";
Range = cast<DefaultStmt>(Term)->getDefaultLoc();
break;
}
S.Diag(Range.getBegin(), diag::warn_sometimes_uninit_var)
<< VD->getDeclName() << IsCapturedByBlock << DiagKind
<< Str << I->Output << Range;
S.Diag(User->getLocStart(), diag::note_uninit_var_use)
<< IsCapturedByBlock << User->getSourceRange();
if (RemoveDiagKind != -1)
S.Diag(Fixit1.RemoveRange.getBegin(), diag::note_uninit_fixit_remove_cond)
<< RemoveDiagKind << Str << I->Output << Fixit1 << Fixit2;
Diagnosed = true;
}
if (!Diagnosed)
S.Diag(Use.getUser()->getLocStart(),
Use.getKind() == UninitUse::Always ? diag::warn_uninit_var
: diag::warn_maybe_uninit_var)
<< VD->getDeclName() << IsCapturedByBlock
<< Use.getUser()->getSourceRange();
}
/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
/// uninitialized variable. This manages the different forms of diagnostic
/// emitted for particular types of uses. Returns true if the use was diagnosed
/// as a warning. If a particular use is one we omit warnings for, returns
/// false.
static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
const UninitUse &Use,
bool alwaysReportSelfInit = false) {
if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Use.getUser())) {
// Inspect the initializer of the variable declaration which is
// being referenced prior to its initialization. We emit
// specialized diagnostics for self-initialization, and we
// specifically avoid warning about self references which take the
// form of:
//
// int x = x;
//
// This is used to indicate to GCC that 'x' is intentionally left
// uninitialized. Proven code paths which access 'x' in
// an uninitialized state after this will still warn.
if (const Expr *Initializer = VD->getInit()) {
if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
return false;
ContainsReference CR(S.Context, DRE);
CR.Visit(const_cast<Expr*>(Initializer));
if (CR.doesContainReference()) {
S.Diag(DRE->getLocStart(),
diag::warn_uninit_self_reference_in_init)
<< VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
return true;
}
}
DiagUninitUse(S, VD, Use, false);
} else {
const BlockExpr *BE = cast<BlockExpr>(Use.getUser());
if (VD->getType()->isBlockPointerType() && !VD->hasAttr<BlocksAttr>())
S.Diag(BE->getLocStart(),
diag::warn_uninit_byref_blockvar_captured_by_block)
<< VD->getDeclName();
else
DiagUninitUse(S, VD, Use, true);
}
// Report where the variable was declared when the use wasn't within
// the initializer of that declaration & we didn't already suggest
// an initialization fixit.
if (!SuggestInitializationFixit(S, VD))
S.Diag(VD->getLocStart(), diag::note_uninit_var_def)
<< VD->getDeclName();
return true;
}
namespace {
class FallthroughMapper : public RecursiveASTVisitor<FallthroughMapper> {
public:
FallthroughMapper(Sema &S)
: FoundSwitchStatements(false),
S(S) {
}
bool foundSwitchStatements() const { return FoundSwitchStatements; }
void markFallthroughVisited(const AttributedStmt *Stmt) {
bool Found = FallthroughStmts.erase(Stmt);
assert(Found);
(void)Found;
}
typedef llvm::SmallPtrSet<const AttributedStmt*, 8> AttrStmts;
const AttrStmts &getFallthroughStmts() const {
return FallthroughStmts;
}
bool checkFallThroughIntoBlock(const CFGBlock &B, int &AnnotatedCnt) {
int UnannotatedCnt = 0;
AnnotatedCnt = 0;
std::deque<const CFGBlock*> BlockQueue;
std::copy(B.pred_begin(), B.pred_end(), std::back_inserter(BlockQueue));
while (!BlockQueue.empty()) {
const CFGBlock *P = BlockQueue.front();
BlockQueue.pop_front();
const Stmt *Term = P->getTerminator();
if (Term && isa<SwitchStmt>(Term))
continue; // Switch statement, good.
const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(P->getLabel());
if (SW && SW->getSubStmt() == B.getLabel() && P->begin() == P->end())
continue; // Previous case label has no statements, good.
if (P->pred_begin() == P->pred_end()) { // The block is unreachable.
// This only catches trivially unreachable blocks.
for (CFGBlock::const_iterator ElIt = P->begin(), ElEnd = P->end();
ElIt != ElEnd; ++ElIt) {
if (const CFGStmt *CS = ElIt->getAs<CFGStmt>()){
if (const AttributedStmt *AS = asFallThroughAttr(CS->getStmt())) {
S.Diag(AS->getLocStart(),
diag::warn_fallthrough_attr_unreachable);
markFallthroughVisited(AS);
++AnnotatedCnt;
}
// Don't care about other unreachable statements.
}
}
// If there are no unreachable statements, this may be a special
// case in CFG:
// case X: {
// A a; // A has a destructor.
// break;
// }
// // <<<< This place is represented by a 'hanging' CFG block.
// case Y:
continue;
}
const Stmt *LastStmt = getLastStmt(*P);
if (const AttributedStmt *AS = asFallThroughAttr(LastStmt)) {
markFallthroughVisited(AS);
++AnnotatedCnt;
continue; // Fallthrough annotation, good.
}
if (!LastStmt) { // This block contains no executable statements.
// Traverse its predecessors.
std::copy(P->pred_begin(), P->pred_end(),
std::back_inserter(BlockQueue));
continue;
}
++UnannotatedCnt;
}
return !!UnannotatedCnt;
}
// RecursiveASTVisitor setup.
bool shouldWalkTypesOfTypeLocs() const { return false; }
bool VisitAttributedStmt(AttributedStmt *S) {
if (asFallThroughAttr(S))
FallthroughStmts.insert(S);
return true;
}
bool VisitSwitchStmt(SwitchStmt *S) {
FoundSwitchStatements = true;
return true;
}
private:
static const AttributedStmt *asFallThroughAttr(const Stmt *S) {
if (const AttributedStmt *AS = dyn_cast_or_null<AttributedStmt>(S)) {
if (hasSpecificAttr<FallThroughAttr>(AS->getAttrs()))
return AS;
}
return 0;
}
static const Stmt *getLastStmt(const CFGBlock &B) {
if (const Stmt *Term = B.getTerminator())
return Term;
for (CFGBlock::const_reverse_iterator ElemIt = B.rbegin(),
ElemEnd = B.rend();
ElemIt != ElemEnd; ++ElemIt) {
if (const CFGStmt *CS = ElemIt->getAs<CFGStmt>())
return CS->getStmt();
}
// Workaround to detect a statement thrown out by CFGBuilder:
// case X: {} case Y:
// case X: ; case Y:
if (const SwitchCase *SW = dyn_cast_or_null<SwitchCase>(B.getLabel()))
if (!isa<SwitchCase>(SW->getSubStmt()))
return SW->getSubStmt();
return 0;
}
bool FoundSwitchStatements;
AttrStmts FallthroughStmts;
Sema &S;
};
}
static void DiagnoseSwitchLabelsFallthrough(Sema &S, AnalysisDeclContext &AC,
bool PerFunction) {
// Only perform this analysis when using C++11. There is no good workflow
// for this warning when not using C++11. There is no good way to silence
// the warning (no attribute is available) unless we are using C++11's support
// for generalized attributes. Once could use pragmas to silence the warning,
// but as a general solution that is gross and not in the spirit of this
// warning.
//
// NOTE: This an intermediate solution. There are on-going discussions on
// how to properly support this warning outside of C++11 with an annotation.
if (!AC.getASTContext().getLangOpts().CPlusPlus0x)
return;
FallthroughMapper FM(S);
FM.TraverseStmt(AC.getBody());
if (!FM.foundSwitchStatements())
return;
if (PerFunction && FM.getFallthroughStmts().empty())
return;
CFG *Cfg = AC.getCFG();
if (!Cfg)
return;
int AnnotatedCnt;
for (CFG::reverse_iterator I = Cfg->rbegin(), E = Cfg->rend(); I != E; ++I) {
const CFGBlock &B = **I;
const Stmt *Label = B.getLabel();
if (!Label || !isa<SwitchCase>(Label))
continue;
if (!FM.checkFallThroughIntoBlock(B, AnnotatedCnt))
continue;
S.Diag(Label->getLocStart(),
PerFunction ? diag::warn_unannotated_fallthrough_per_function
: diag::warn_unannotated_fallthrough);
if (!AnnotatedCnt) {
SourceLocation L = Label->getLocStart();
if (L.isMacroID())
continue;
if (S.getLangOpts().CPlusPlus0x) {
const Stmt *Term = B.getTerminator();
if (!(B.empty() && Term && isa<BreakStmt>(Term))) {
Preprocessor &PP = S.getPreprocessor();
TokenValue Tokens[] = {
tok::l_square, tok::l_square, PP.getIdentifierInfo("clang"),
tok::coloncolon, PP.getIdentifierInfo("fallthrough"),
tok::r_square, tok::r_square
};
StringRef AnnotationSpelling = "[[clang::fallthrough]]";
StringRef MacroName = PP.getLastMacroWithSpelling(L, Tokens);
if (!MacroName.empty())
AnnotationSpelling = MacroName;
SmallString<64> TextToInsert(AnnotationSpelling);
TextToInsert += "; ";
S.Diag(L, diag::note_insert_fallthrough_fixit) <<
AnnotationSpelling <<
FixItHint::CreateInsertion(L, TextToInsert);
}
}
S.Diag(L, diag::note_insert_break_fixit) <<
FixItHint::CreateInsertion(L, "break; ");
}
}
const FallthroughMapper::AttrStmts &Fallthroughs = FM.getFallthroughStmts();
for (FallthroughMapper::AttrStmts::const_iterator I = Fallthroughs.begin(),
E = Fallthroughs.end();
I != E; ++I) {
S.Diag((*I)->getLocStart(), diag::warn_fallthrough_attr_invalid_placement);
}
}
namespace {
typedef std::pair<const Stmt *,
sema::FunctionScopeInfo::WeakObjectUseMap::const_iterator>
StmtUsesPair;
class StmtUseSorter {
const SourceManager &SM;
public:
explicit StmtUseSorter(const SourceManager &SM) : SM(SM) { }
bool operator()(const StmtUsesPair &LHS, const StmtUsesPair &RHS) {
return SM.isBeforeInTranslationUnit(LHS.first->getLocStart(),
RHS.first->getLocStart());
}
};
}
static bool isInLoop(const ASTContext &Ctx, const ParentMap &PM,
const Stmt *S) {
assert(S);
do {
switch (S->getStmtClass()) {
case Stmt::ForStmtClass:
case Stmt::WhileStmtClass:
case Stmt::CXXForRangeStmtClass:
case Stmt::ObjCForCollectionStmtClass:
return true;
case Stmt::DoStmtClass: {
const Expr *Cond = cast<DoStmt>(S)->getCond();
llvm::APSInt Val;
if (!Cond->EvaluateAsInt(Val, Ctx))
return true;
return Val.getBoolValue();
}
default:
break;
}
} while ((S = PM.getParent(S)));
return false;
}
static void diagnoseRepeatedUseOfWeak(Sema &S,
const sema::FunctionScopeInfo *CurFn,
const Decl *D,
const ParentMap &PM) {
typedef sema::FunctionScopeInfo::WeakObjectProfileTy WeakObjectProfileTy;
typedef sema::FunctionScopeInfo::WeakObjectUseMap WeakObjectUseMap;
typedef sema::FunctionScopeInfo::WeakUseVector WeakUseVector;
ASTContext &Ctx = S.getASTContext();
const WeakObjectUseMap &WeakMap = CurFn->getWeakObjectUses();
// Extract all weak objects that are referenced more than once.
SmallVector<StmtUsesPair, 8> UsesByStmt;
for (WeakObjectUseMap::const_iterator I = WeakMap.begin(), E = WeakMap.end();
I != E; ++I) {
const WeakUseVector &Uses = I->second;
// Find the first read of the weak object.
WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
for ( ; UI != UE; ++UI) {
if (UI->isUnsafe())
break;
}
// If there were only writes to this object, don't warn.
if (UI == UE)
continue;
// If there was only one read, followed by any number of writes, and the
// read is not within a loop, don't warn. Additionally, don't warn in a
// loop if the base object is a local variable -- local variables are often
// changed in loops.
if (UI == Uses.begin()) {
WeakUseVector::const_iterator UI2 = UI;
for (++UI2; UI2 != UE; ++UI2)
if (UI2->isUnsafe())
break;
if (UI2 == UE) {
if (!isInLoop(Ctx, PM, UI->getUseExpr()))
continue;
const WeakObjectProfileTy &Profile = I->first;
if (!Profile.isExactProfile())
continue;
const NamedDecl *Base = Profile.getBase();
if (!Base)
Base = Profile.getProperty();
assert(Base && "A profile always has a base or property.");
if (const VarDecl *BaseVar = dyn_cast<VarDecl>(Base))
if (BaseVar->hasLocalStorage() && !isa<ParmVarDecl>(Base))
continue;
}
}
UsesByStmt.push_back(StmtUsesPair(UI->getUseExpr(), I));
}
if (UsesByStmt.empty())
return;
// Sort by first use so that we emit the warnings in a deterministic order.
std::sort(UsesByStmt.begin(), UsesByStmt.end(),
StmtUseSorter(S.getSourceManager()));
// Classify the current code body for better warning text.
// This enum should stay in sync with the cases in
// warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
// FIXME: Should we use a common classification enum and the same set of
// possibilities all throughout Sema?
enum {
Function,
Method,
Block,
Lambda
} FunctionKind;
if (isa<sema::BlockScopeInfo>(CurFn))
FunctionKind = Block;
else if (isa<sema::LambdaScopeInfo>(CurFn))
FunctionKind = Lambda;
else if (isa<ObjCMethodDecl>(D))
FunctionKind = Method;
else
FunctionKind = Function;
// Iterate through the sorted problems and emit warnings for each.
for (SmallVectorImpl<StmtUsesPair>::const_iterator I = UsesByStmt.begin(),
E = UsesByStmt.end();
I != E; ++I) {
const Stmt *FirstRead = I->first;
const WeakObjectProfileTy &Key = I->second->first;
const WeakUseVector &Uses = I->second->second;
// For complicated expressions like 'a.b.c' and 'x.b.c', WeakObjectProfileTy
// may not contain enough information to determine that these are different
// properties. We can only be 100% sure of a repeated use in certain cases,
// and we adjust the diagnostic kind accordingly so that the less certain
// case can be turned off if it is too noisy.
unsigned DiagKind;
if (Key.isExactProfile())
DiagKind = diag::warn_arc_repeated_use_of_weak;
else
DiagKind = diag::warn_arc_possible_repeated_use_of_weak;
// Classify the weak object being accessed for better warning text.
// This enum should stay in sync with the cases in
// warn_arc_repeated_use_of_weak and warn_arc_possible_repeated_use_of_weak.
enum {
Variable,
Property,
ImplicitProperty,
Ivar
} ObjectKind;
const NamedDecl *D = Key.getProperty();
if (isa<VarDecl>(D))
ObjectKind = Variable;
else if (isa<ObjCPropertyDecl>(D))
ObjectKind = Property;
else if (isa<ObjCMethodDecl>(D))
ObjectKind = ImplicitProperty;
else if (isa<ObjCIvarDecl>(D))
ObjectKind = Ivar;
else
llvm_unreachable("Unexpected weak object kind!");
// Show the first time the object was read.
S.Diag(FirstRead->getLocStart(), DiagKind)
<< ObjectKind << D << FunctionKind
<< FirstRead->getSourceRange();
// Print all the other accesses as notes.
for (WeakUseVector::const_iterator UI = Uses.begin(), UE = Uses.end();
UI != UE; ++UI) {
if (UI->getUseExpr() == FirstRead)
continue;
S.Diag(UI->getUseExpr()->getLocStart(),
diag::note_arc_weak_also_accessed_here)
<< UI->getUseExpr()->getSourceRange();
}
}
}
namespace {
struct SLocSort {
bool operator()(const UninitUse &a, const UninitUse &b) {
// Prefer a more confident report over a less confident one.
if (a.getKind() != b.getKind())
return a.getKind() > b.getKind();
SourceLocation aLoc = a.getUser()->getLocStart();
SourceLocation bLoc = b.getUser()->getLocStart();
return aLoc.getRawEncoding() < bLoc.getRawEncoding();
}
};
class UninitValsDiagReporter : public UninitVariablesHandler {
Sema &S;
typedef SmallVector<UninitUse, 2> UsesVec;
typedef llvm::DenseMap<const VarDecl *, std::pair<UsesVec*, bool> > UsesMap;
UsesMap *uses;
public:
UninitValsDiagReporter(Sema &S) : S(S), uses(0) {}
~UninitValsDiagReporter() {
flushDiagnostics();
}
std::pair<UsesVec*, bool> &getUses(const VarDecl *vd) {
if (!uses)
uses = new UsesMap();
UsesMap::mapped_type &V = (*uses)[vd];
UsesVec *&vec = V.first;
if (!vec)
vec = new UsesVec();
return V;
}
void handleUseOfUninitVariable(const VarDecl *vd, const UninitUse &use) {
getUses(vd).first->push_back(use);
}
void handleSelfInit(const VarDecl *vd) {
getUses(vd).second = true;
}
void flushDiagnostics() {
if (!uses)
return;
// FIXME: This iteration order, and thus the resulting diagnostic order,
// is nondeterministic.
for (UsesMap::iterator i = uses->begin(), e = uses->end(); i != e; ++i) {
const VarDecl *vd = i->first;
const UsesMap::mapped_type &V = i->second;
UsesVec *vec = V.first;
bool hasSelfInit = V.second;
// Specially handle the case where we have uses of an uninitialized
// variable, but the root cause is an idiomatic self-init. We want
// to report the diagnostic at the self-init since that is the root cause.
if (!vec->empty() && hasSelfInit && hasAlwaysUninitializedUse(vec))
DiagnoseUninitializedUse(S, vd,
UninitUse(vd->getInit()->IgnoreParenCasts(),
/* isAlwaysUninit */ true),
/* alwaysReportSelfInit */ true);
else {
// Sort the uses by their SourceLocations. While not strictly
// guaranteed to produce them in line/column order, this will provide
// a stable ordering.
std::sort(vec->begin(), vec->end(), SLocSort());
for (UsesVec::iterator vi = vec->begin(), ve = vec->end(); vi != ve;
++vi) {
// If we have self-init, downgrade all uses to 'may be uninitialized'.
UninitUse Use = hasSelfInit ? UninitUse(vi->getUser(), false) : *vi;
if (DiagnoseUninitializedUse(S, vd, Use))
// Skip further diagnostics for this variable. We try to warn only
// on the first point at which a variable is used uninitialized.
break;
}
}
// Release the uses vector.
delete vec;
}
delete uses;
}
private:
static bool hasAlwaysUninitializedUse(const UsesVec* vec) {
for (UsesVec::const_iterator i = vec->begin(), e = vec->end(); i != e; ++i) {
if (i->getKind() == UninitUse::Always) {
return true;
}
}
return false;
}
};
}
//===----------------------------------------------------------------------===//
// -Wthread-safety
//===----------------------------------------------------------------------===//
namespace clang {
namespace thread_safety {
typedef llvm::SmallVector<PartialDiagnosticAt, 1> OptionalNotes;
typedef std::pair<PartialDiagnosticAt, OptionalNotes> DelayedDiag;
typedef std::list<DelayedDiag> DiagList;
struct SortDiagBySourceLocation {
SourceManager &SM;
SortDiagBySourceLocation(SourceManager &SM) : SM(SM) {}
bool operator()(const DelayedDiag &left, const DelayedDiag &right) {
// Although this call will be slow, this is only called when outputting
// multiple warnings.
return SM.isBeforeInTranslationUnit(left.first.first, right.first.first);
}
};
namespace {
class ThreadSafetyReporter : public clang::thread_safety::ThreadSafetyHandler {
Sema &S;
DiagList Warnings;
SourceLocation FunLocation, FunEndLocation;
// Helper functions
void warnLockMismatch(unsigned DiagID, Name LockName, SourceLocation Loc) {
// Gracefully handle rare cases when the analysis can't get a more
// precise source location.
if (!Loc.isValid())
Loc = FunLocation;
PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID) << LockName);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
}
public:
ThreadSafetyReporter(Sema &S, SourceLocation FL, SourceLocation FEL)
: S(S), FunLocation(FL), FunEndLocation(FEL) {}
/// \brief Emit all buffered diagnostics in order of sourcelocation.
/// We need to output diagnostics produced while iterating through
/// the lockset in deterministic order, so this function orders diagnostics
/// and outputs them.
void emitDiagnostics() {
Warnings.sort(SortDiagBySourceLocation(S.getSourceManager()));
for (DiagList::iterator I = Warnings.begin(), E = Warnings.end();
I != E; ++I) {
S.Diag(I->first.first, I->first.second);
const OptionalNotes &Notes = I->second;
for (unsigned NoteI = 0, NoteN = Notes.size(); NoteI != NoteN; ++NoteI)
S.Diag(Notes[NoteI].first, Notes[NoteI].second);
}
}
void handleInvalidLockExp(SourceLocation Loc) {
PartialDiagnosticAt Warning(Loc,
S.PDiag(diag::warn_cannot_resolve_lock) << Loc);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
}
void handleUnmatchedUnlock(Name LockName, SourceLocation Loc) {
warnLockMismatch(diag::warn_unlock_but_no_lock, LockName, Loc);
}
void handleDoubleLock(Name LockName, SourceLocation Loc) {
warnLockMismatch(diag::warn_double_lock, LockName, Loc);
}
void handleMutexHeldEndOfScope(Name LockName, SourceLocation LocLocked,
SourceLocation LocEndOfScope,
LockErrorKind LEK){
unsigned DiagID = 0;
switch (LEK) {
case LEK_LockedSomePredecessors:
DiagID = diag::warn_lock_some_predecessors;
break;
case LEK_LockedSomeLoopIterations:
DiagID = diag::warn_expecting_lock_held_on_loop;
break;
case LEK_LockedAtEndOfFunction:
DiagID = diag::warn_no_unlock;
break;
case LEK_NotLockedAtEndOfFunction:
DiagID = diag::warn_expecting_locked;
break;
}
if (LocEndOfScope.isInvalid())
LocEndOfScope = FunEndLocation;
PartialDiagnosticAt Warning(LocEndOfScope, S.PDiag(DiagID) << LockName);
PartialDiagnosticAt Note(LocLocked, S.PDiag(diag::note_locked_here));
Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
}
void handleExclusiveAndShared(Name LockName, SourceLocation Loc1,
SourceLocation Loc2) {
PartialDiagnosticAt Warning(
Loc1, S.PDiag(diag::warn_lock_exclusive_and_shared) << LockName);
PartialDiagnosticAt Note(
Loc2, S.PDiag(diag::note_lock_exclusive_and_shared) << LockName);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
}
void handleNoMutexHeld(const NamedDecl *D, ProtectedOperationKind POK,
AccessKind AK, SourceLocation Loc) {
assert((POK == POK_VarAccess || POK == POK_VarDereference)
&& "Only works for variables");
unsigned DiagID = POK == POK_VarAccess?
diag::warn_variable_requires_any_lock:
diag::warn_var_deref_requires_any_lock;
PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
<< D->getNameAsString() << getLockKindFromAccessKind(AK));
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
}
void handleMutexNotHeld(const NamedDecl *D, ProtectedOperationKind POK,
Name LockName, LockKind LK, SourceLocation Loc,
Name *PossibleMatch) {
unsigned DiagID = 0;
if (PossibleMatch) {
switch (POK) {
case POK_VarAccess:
DiagID = diag::warn_variable_requires_lock_precise;
break;
case POK_VarDereference:
DiagID = diag::warn_var_deref_requires_lock_precise;
break;
case POK_FunctionCall:
DiagID = diag::warn_fun_requires_lock_precise;
break;
}
PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
<< D->getNameAsString() << LockName << LK);
PartialDiagnosticAt Note(Loc, S.PDiag(diag::note_found_mutex_near_match)
<< *PossibleMatch);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes(1, Note)));
} else {
switch (POK) {
case POK_VarAccess:
DiagID = diag::warn_variable_requires_lock;
break;
case POK_VarDereference:
DiagID = diag::warn_var_deref_requires_lock;
break;
case POK_FunctionCall:
DiagID = diag::warn_fun_requires_lock;
break;
}
PartialDiagnosticAt Warning(Loc, S.PDiag(DiagID)
<< D->getNameAsString() << LockName << LK);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
}
}
void handleFunExcludesLock(Name FunName, Name LockName, SourceLocation Loc) {
PartialDiagnosticAt Warning(Loc,
S.PDiag(diag::warn_fun_excludes_mutex) << FunName << LockName);
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
}
};
}
}
}
//===----------------------------------------------------------------------===//
// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
// warnings on a function, method, or block.
//===----------------------------------------------------------------------===//
clang::sema::AnalysisBasedWarnings::Policy::Policy() {
enableCheckFallThrough = 1;
enableCheckUnreachable = 0;
enableThreadSafetyAnalysis = 0;
}
clang::sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
: S(s),
NumFunctionsAnalyzed(0),
NumFunctionsWithBadCFGs(0),
NumCFGBlocks(0),
MaxCFGBlocksPerFunction(0),
NumUninitAnalysisFunctions(0),
NumUninitAnalysisVariables(0),
MaxUninitAnalysisVariablesPerFunction(0),
NumUninitAnalysisBlockVisits(0),
MaxUninitAnalysisBlockVisitsPerFunction(0) {
DiagnosticsEngine &D = S.getDiagnostics();
DefaultPolicy.enableCheckUnreachable = (unsigned)
(D.getDiagnosticLevel(diag::warn_unreachable, SourceLocation()) !=
DiagnosticsEngine::Ignored);
DefaultPolicy.enableThreadSafetyAnalysis = (unsigned)
(D.getDiagnosticLevel(diag::warn_double_lock, SourceLocation()) !=
DiagnosticsEngine::Ignored);
}
static void flushDiagnostics(Sema &S, sema::FunctionScopeInfo *fscope) {
for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
i = fscope->PossiblyUnreachableDiags.begin(),
e = fscope->PossiblyUnreachableDiags.end();
i != e; ++i) {
const sema::PossiblyUnreachableDiag &D = *i;
S.Diag(D.Loc, D.PD);
}
}
void clang::sema::
AnalysisBasedWarnings::IssueWarnings(sema::AnalysisBasedWarnings::Policy P,
sema::FunctionScopeInfo *fscope,
const Decl *D, const BlockExpr *blkExpr) {
// We avoid doing analysis-based warnings when there are errors for
// two reasons:
// (1) The CFGs often can't be constructed (if the body is invalid), so
// don't bother trying.
// (2) The code already has problems; running the analysis just takes more
// time.
DiagnosticsEngine &Diags = S.getDiagnostics();
// Do not do any analysis for declarations in system headers if we are
// going to just ignore them.
if (Diags.getSuppressSystemWarnings() &&
S.SourceMgr.isInSystemHeader(D->getLocation()))
return;
// For code in dependent contexts, we'll do this at instantiation time.
if (cast<DeclContext>(D)->isDependentContext())
return;
if (Diags.hasErrorOccurred() || Diags.hasFatalErrorOccurred()) {
// Flush out any possibly unreachable diagnostics.
flushDiagnostics(S, fscope);
return;
}
const Stmt *Body = D->getBody();
assert(Body);
AnalysisDeclContext AC(/* AnalysisDeclContextManager */ 0, D);
// Don't generate EH edges for CallExprs as we'd like to avoid the n^2
// explosion for destrutors that can result and the compile time hit.
AC.getCFGBuildOptions().PruneTriviallyFalseEdges = true;
AC.getCFGBuildOptions().AddEHEdges = false;
AC.getCFGBuildOptions().AddInitializers = true;
AC.getCFGBuildOptions().AddImplicitDtors = true;
AC.getCFGBuildOptions().AddTemporaryDtors = true;
// Force that certain expressions appear as CFGElements in the CFG. This
// is used to speed up various analyses.
// FIXME: This isn't the right factoring. This is here for initial
// prototyping, but we need a way for analyses to say what expressions they
// expect to always be CFGElements and then fill in the BuildOptions
// appropriately. This is essentially a layering violation.
if (P.enableCheckUnreachable || P.enableThreadSafetyAnalysis) {
// Unreachable code analysis and thread safety require a linearized CFG.
AC.getCFGBuildOptions().setAllAlwaysAdd();
}
else {
AC.getCFGBuildOptions()
.setAlwaysAdd(Stmt::BinaryOperatorClass)
.setAlwaysAdd(Stmt::CompoundAssignOperatorClass)
.setAlwaysAdd(Stmt::BlockExprClass)
.setAlwaysAdd(Stmt::CStyleCastExprClass)
.setAlwaysAdd(Stmt::DeclRefExprClass)
.setAlwaysAdd(Stmt::ImplicitCastExprClass)
.setAlwaysAdd(Stmt::UnaryOperatorClass)
.setAlwaysAdd(Stmt::AttributedStmtClass);
}
// Construct the analysis context with the specified CFG build options.
// Emit delayed diagnostics.
if (!fscope->PossiblyUnreachableDiags.empty()) {
bool analyzed = false;
// Register the expressions with the CFGBuilder.
for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
i = fscope->PossiblyUnreachableDiags.begin(),
e = fscope->PossiblyUnreachableDiags.end();
i != e; ++i) {
if (const Stmt *stmt = i->stmt)
AC.registerForcedBlockExpression(stmt);
}
if (AC.getCFG()) {
analyzed = true;
for (SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
i = fscope->PossiblyUnreachableDiags.begin(),
e = fscope->PossiblyUnreachableDiags.end();
i != e; ++i)
{
const sema::PossiblyUnreachableDiag &D = *i;
bool processed = false;
if (const Stmt *stmt = i->stmt) {
const CFGBlock *block = AC.getBlockForRegisteredExpression(stmt);
CFGReverseBlockReachabilityAnalysis *cra =
AC.getCFGReachablityAnalysis();
// FIXME: We should be able to assert that block is non-null, but
// the CFG analysis can skip potentially-evaluated expressions in
// edge cases; see test/Sema/vla-2.c.
if (block && cra) {
// Can this block be reached from the entrance?
if (cra->isReachable(&AC.getCFG()->getEntry(), block))
S.Diag(D.Loc, D.PD);
processed = true;
}
}
if (!processed) {
// Emit the warning anyway if we cannot map to a basic block.
S.Diag(D.Loc, D.PD);
}
}
}
if (!analyzed)
flushDiagnostics(S, fscope);
}
// Warning: check missing 'return'
if (P.enableCheckFallThrough) {
const CheckFallThroughDiagnostics &CD =
(isa<BlockDecl>(D) ? CheckFallThroughDiagnostics::MakeForBlock()
: (isa<CXXMethodDecl>(D) &&
cast<CXXMethodDecl>(D)->getOverloadedOperator() == OO_Call &&
cast<CXXMethodDecl>(D)->getParent()->isLambda())
? CheckFallThroughDiagnostics::MakeForLambda()
: CheckFallThroughDiagnostics::MakeForFunction(D));
CheckFallThroughForBody(S, D, Body, blkExpr, CD, AC);
}
// Warning: check for unreachable code
if (P.enableCheckUnreachable) {
// Only check for unreachable code on non-template instantiations.
// Different template instantiations can effectively change the control-flow
// and it is very difficult to prove that a snippet of code in a template
// is unreachable for all instantiations.
bool isTemplateInstantiation = false;
if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
isTemplateInstantiation = Function->isTemplateInstantiation();
if (!isTemplateInstantiation)
CheckUnreachable(S, AC);
}
// Check for thread safety violations
if (P.enableThreadSafetyAnalysis) {
SourceLocation FL = AC.getDecl()->getLocation();
SourceLocation FEL = AC.getDecl()->getLocEnd();
thread_safety::ThreadSafetyReporter Reporter(S, FL, FEL);
thread_safety::runThreadSafetyAnalysis(AC, Reporter);
Reporter.emitDiagnostics();
}
if (Diags.getDiagnosticLevel(diag::warn_uninit_var, D->getLocStart())
!= DiagnosticsEngine::Ignored ||
Diags.getDiagnosticLevel(diag::warn_sometimes_uninit_var,D->getLocStart())
!= DiagnosticsEngine::Ignored ||
Diags.getDiagnosticLevel(diag::warn_maybe_uninit_var, D->getLocStart())
!= DiagnosticsEngine::Ignored) {
if (CFG *cfg = AC.getCFG()) {
UninitValsDiagReporter reporter(S);
UninitVariablesAnalysisStats stats;
std::memset(&stats, 0, sizeof(UninitVariablesAnalysisStats));
runUninitializedVariablesAnalysis(*cast<DeclContext>(D), *cfg, AC,
reporter, stats);
if (S.CollectStats && stats.NumVariablesAnalyzed > 0) {
++NumUninitAnalysisFunctions;
NumUninitAnalysisVariables += stats.NumVariablesAnalyzed;
NumUninitAnalysisBlockVisits += stats.NumBlockVisits;
MaxUninitAnalysisVariablesPerFunction =
std::max(MaxUninitAnalysisVariablesPerFunction,
stats.NumVariablesAnalyzed);
MaxUninitAnalysisBlockVisitsPerFunction =
std::max(MaxUninitAnalysisBlockVisitsPerFunction,
stats.NumBlockVisits);
}
}
}
bool FallThroughDiagFull =
Diags.getDiagnosticLevel(diag::warn_unannotated_fallthrough,
D->getLocStart()) != DiagnosticsEngine::Ignored;
bool FallThroughDiagPerFunction =
Diags.getDiagnosticLevel(diag::warn_unannotated_fallthrough_per_function,
D->getLocStart()) != DiagnosticsEngine::Ignored;
if (FallThroughDiagFull || FallThroughDiagPerFunction) {
DiagnoseSwitchLabelsFallthrough(S, AC, !FallThroughDiagFull);
}
if (S.getLangOpts().ObjCARCWeak &&
Diags.getDiagnosticLevel(diag::warn_arc_repeated_use_of_weak,
D->getLocStart()) != DiagnosticsEngine::Ignored)
diagnoseRepeatedUseOfWeak(S, fscope, D, AC.getParentMap());
// Collect statistics about the CFG if it was built.
if (S.CollectStats && AC.isCFGBuilt()) {
++NumFunctionsAnalyzed;
if (CFG *cfg = AC.getCFG()) {
// If we successfully built a CFG for this context, record some more
// detail information about it.
NumCFGBlocks += cfg->getNumBlockIDs();
MaxCFGBlocksPerFunction = std::max(MaxCFGBlocksPerFunction,
cfg->getNumBlockIDs());
} else {
++NumFunctionsWithBadCFGs;
}
}
}
void clang::sema::AnalysisBasedWarnings::PrintStats() const {
llvm::errs() << "\n*** Analysis Based Warnings Stats:\n";
unsigned NumCFGsBuilt = NumFunctionsAnalyzed - NumFunctionsWithBadCFGs;
unsigned AvgCFGBlocksPerFunction =
!NumCFGsBuilt ? 0 : NumCFGBlocks/NumCFGsBuilt;
llvm::errs() << NumFunctionsAnalyzed << " functions analyzed ("
<< NumFunctionsWithBadCFGs << " w/o CFGs).\n"
<< " " << NumCFGBlocks << " CFG blocks built.\n"
<< " " << AvgCFGBlocksPerFunction
<< " average CFG blocks per function.\n"
<< " " << MaxCFGBlocksPerFunction
<< " max CFG blocks per function.\n";
unsigned AvgUninitVariablesPerFunction = !NumUninitAnalysisFunctions ? 0
: NumUninitAnalysisVariables/NumUninitAnalysisFunctions;
unsigned AvgUninitBlockVisitsPerFunction = !NumUninitAnalysisFunctions ? 0
: NumUninitAnalysisBlockVisits/NumUninitAnalysisFunctions;
llvm::errs() << NumUninitAnalysisFunctions
<< " functions analyzed for uninitialiazed variables\n"
<< " " << NumUninitAnalysisVariables << " variables analyzed.\n"
<< " " << AvgUninitVariablesPerFunction
<< " average variables per function.\n"
<< " " << MaxUninitAnalysisVariablesPerFunction
<< " max variables per function.\n"
<< " " << NumUninitAnalysisBlockVisits << " block visits.\n"
<< " " << AvgUninitBlockVisitsPerFunction
<< " average block visits per function.\n"
<< " " << MaxUninitAnalysisBlockVisitsPerFunction
<< " max block visits per function.\n";
}