forked from OSchip/llvm-project
1017 lines
37 KiB
C++
1017 lines
37 KiB
C++
//=- AnalysisBasedWarnings.cpp - Sema warnings based on libAnalysis -*- C++ -*-=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines analysis_warnings::[Policy,Executor].
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// Together they are used by Sema to issue warnings based on inexpensive
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// static analysis algorithms in libAnalysis.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/Sema/AnalysisBasedWarnings.h"
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#include "clang/Sema/SemaInternal.h"
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#include "clang/Sema/ScopeInfo.h"
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#include "clang/Basic/SourceManager.h"
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#include "clang/Basic/SourceLocation.h"
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#include "clang/Lex/Preprocessor.h"
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#include "clang/AST/DeclObjC.h"
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#include "clang/AST/DeclCXX.h"
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#include "clang/AST/ExprObjC.h"
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#include "clang/AST/ExprCXX.h"
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#include "clang/AST/StmtObjC.h"
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#include "clang/AST/StmtCXX.h"
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#include "clang/AST/EvaluatedExprVisitor.h"
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#include "clang/AST/StmtVisitor.h"
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#include "clang/Analysis/AnalysisContext.h"
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#include "clang/Analysis/CFG.h"
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#include "clang/Analysis/Analyses/ReachableCode.h"
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#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
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#include "clang/Analysis/Analyses/ThreadSafety.h"
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#include "clang/Analysis/CFGStmtMap.h"
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#include "clang/Analysis/Analyses/UninitializedValues.h"
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#include "llvm/ADT/BitVector.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/ImmutableMap.h"
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#include "llvm/ADT/PostOrderIterator.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/Casting.h"
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#include <algorithm>
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#include <vector>
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using namespace clang;
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//===----------------------------------------------------------------------===//
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// Unreachable code analysis.
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//===----------------------------------------------------------------------===//
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namespace {
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class UnreachableCodeHandler : public reachable_code::Callback {
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Sema &S;
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public:
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UnreachableCodeHandler(Sema &s) : S(s) {}
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void HandleUnreachable(SourceLocation L, SourceRange R1, SourceRange R2) {
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S.Diag(L, diag::warn_unreachable) << R1 << R2;
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}
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};
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}
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/// CheckUnreachable - Check for unreachable code.
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static void CheckUnreachable(Sema &S, AnalysisDeclContext &AC) {
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UnreachableCodeHandler UC(S);
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reachable_code::FindUnreachableCode(AC, UC);
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}
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//===----------------------------------------------------------------------===//
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// Check for missing return value.
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//===----------------------------------------------------------------------===//
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enum ControlFlowKind {
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UnknownFallThrough,
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NeverFallThrough,
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MaybeFallThrough,
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AlwaysFallThrough,
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NeverFallThroughOrReturn
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};
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/// CheckFallThrough - Check that we don't fall off the end of a
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/// Statement that should return a value.
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///
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/// \returns AlwaysFallThrough iff we always fall off the end of the statement,
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/// MaybeFallThrough iff we might or might not fall off the end,
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/// NeverFallThroughOrReturn iff we never fall off the end of the statement or
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/// return. We assume NeverFallThrough iff we never fall off the end of the
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/// statement but we may return. We assume that functions not marked noreturn
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/// will return.
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static ControlFlowKind CheckFallThrough(AnalysisDeclContext &AC) {
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CFG *cfg = AC.getCFG();
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if (cfg == 0) return UnknownFallThrough;
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// The CFG leaves in dead things, and we don't want the dead code paths to
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// confuse us, so we mark all live things first.
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llvm::BitVector live(cfg->getNumBlockIDs());
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unsigned count = reachable_code::ScanReachableFromBlock(&cfg->getEntry(),
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live);
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bool AddEHEdges = AC.getAddEHEdges();
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if (!AddEHEdges && count != cfg->getNumBlockIDs())
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// When there are things remaining dead, and we didn't add EH edges
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// from CallExprs to the catch clauses, we have to go back and
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// mark them as live.
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for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
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CFGBlock &b = **I;
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if (!live[b.getBlockID()]) {
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if (b.pred_begin() == b.pred_end()) {
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if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator()))
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// When not adding EH edges from calls, catch clauses
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// can otherwise seem dead. Avoid noting them as dead.
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count += reachable_code::ScanReachableFromBlock(&b, live);
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continue;
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}
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}
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}
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// Now we know what is live, we check the live precessors of the exit block
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// and look for fall through paths, being careful to ignore normal returns,
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// and exceptional paths.
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bool HasLiveReturn = false;
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bool HasFakeEdge = false;
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bool HasPlainEdge = false;
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bool HasAbnormalEdge = false;
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// Ignore default cases that aren't likely to be reachable because all
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// enums in a switch(X) have explicit case statements.
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CFGBlock::FilterOptions FO;
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FO.IgnoreDefaultsWithCoveredEnums = 1;
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for (CFGBlock::filtered_pred_iterator
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I = cfg->getExit().filtered_pred_start_end(FO); I.hasMore(); ++I) {
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const CFGBlock& B = **I;
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if (!live[B.getBlockID()])
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continue;
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// Skip blocks which contain an element marked as no-return. They don't
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// represent actually viable edges into the exit block, so mark them as
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// abnormal.
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if (B.hasNoReturnElement()) {
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HasAbnormalEdge = true;
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continue;
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}
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// Destructors can appear after the 'return' in the CFG. This is
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// normal. We need to look pass the destructors for the return
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// statement (if it exists).
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CFGBlock::const_reverse_iterator ri = B.rbegin(), re = B.rend();
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for ( ; ri != re ; ++ri)
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if (isa<CFGStmt>(*ri))
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break;
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// No more CFGElements in the block?
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if (ri == re) {
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if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
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HasAbnormalEdge = true;
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continue;
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}
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// A labeled empty statement, or the entry block...
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HasPlainEdge = true;
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continue;
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}
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CFGStmt CS = cast<CFGStmt>(*ri);
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const Stmt *S = CS.getStmt();
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if (isa<ReturnStmt>(S)) {
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HasLiveReturn = true;
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continue;
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}
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if (isa<ObjCAtThrowStmt>(S)) {
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HasFakeEdge = true;
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continue;
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}
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if (isa<CXXThrowExpr>(S)) {
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HasFakeEdge = true;
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continue;
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}
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if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) {
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if (AS->isMSAsm()) {
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HasFakeEdge = true;
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HasLiveReturn = true;
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continue;
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}
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}
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if (isa<CXXTryStmt>(S)) {
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HasAbnormalEdge = true;
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continue;
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}
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if (std::find(B.succ_begin(), B.succ_end(), &cfg->getExit())
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== B.succ_end()) {
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HasAbnormalEdge = true;
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continue;
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}
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HasPlainEdge = true;
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}
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if (!HasPlainEdge) {
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if (HasLiveReturn)
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return NeverFallThrough;
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return NeverFallThroughOrReturn;
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}
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if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn)
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return MaybeFallThrough;
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// This says AlwaysFallThrough for calls to functions that are not marked
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// noreturn, that don't return. If people would like this warning to be more
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// accurate, such functions should be marked as noreturn.
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return AlwaysFallThrough;
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}
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namespace {
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struct CheckFallThroughDiagnostics {
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unsigned diag_MaybeFallThrough_HasNoReturn;
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unsigned diag_MaybeFallThrough_ReturnsNonVoid;
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unsigned diag_AlwaysFallThrough_HasNoReturn;
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unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
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unsigned diag_NeverFallThroughOrReturn;
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enum { Function, Block, Lambda } funMode;
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SourceLocation FuncLoc;
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static CheckFallThroughDiagnostics MakeForFunction(const Decl *Func) {
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CheckFallThroughDiagnostics D;
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D.FuncLoc = Func->getLocation();
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D.diag_MaybeFallThrough_HasNoReturn =
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diag::warn_falloff_noreturn_function;
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D.diag_MaybeFallThrough_ReturnsNonVoid =
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diag::warn_maybe_falloff_nonvoid_function;
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D.diag_AlwaysFallThrough_HasNoReturn =
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diag::warn_falloff_noreturn_function;
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D.diag_AlwaysFallThrough_ReturnsNonVoid =
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diag::warn_falloff_nonvoid_function;
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// Don't suggest that virtual functions be marked "noreturn", since they
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// might be overridden by non-noreturn functions.
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bool isVirtualMethod = false;
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if (const CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Func))
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isVirtualMethod = Method->isVirtual();
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// Don't suggest that template instantiations be marked "noreturn"
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bool isTemplateInstantiation = false;
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if (const FunctionDecl *Function = dyn_cast<FunctionDecl>(Func))
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isTemplateInstantiation = Function->isTemplateInstantiation();
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if (!isVirtualMethod && !isTemplateInstantiation)
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D.diag_NeverFallThroughOrReturn =
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diag::warn_suggest_noreturn_function;
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else
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D.diag_NeverFallThroughOrReturn = 0;
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D.funMode = Function;
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return D;
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}
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static CheckFallThroughDiagnostics MakeForBlock() {
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CheckFallThroughDiagnostics D;
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D.diag_MaybeFallThrough_HasNoReturn =
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diag::err_noreturn_block_has_return_expr;
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D.diag_MaybeFallThrough_ReturnsNonVoid =
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diag::err_maybe_falloff_nonvoid_block;
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D.diag_AlwaysFallThrough_HasNoReturn =
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diag::err_noreturn_block_has_return_expr;
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D.diag_AlwaysFallThrough_ReturnsNonVoid =
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diag::err_falloff_nonvoid_block;
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D.diag_NeverFallThroughOrReturn =
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diag::warn_suggest_noreturn_block;
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D.funMode = Block;
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return D;
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}
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static CheckFallThroughDiagnostics MakeForLambda() {
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CheckFallThroughDiagnostics D;
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D.diag_MaybeFallThrough_HasNoReturn =
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diag::err_noreturn_lambda_has_return_expr;
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D.diag_MaybeFallThrough_ReturnsNonVoid =
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diag::warn_maybe_falloff_nonvoid_lambda;
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D.diag_AlwaysFallThrough_HasNoReturn =
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diag::err_noreturn_lambda_has_return_expr;
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D.diag_AlwaysFallThrough_ReturnsNonVoid =
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diag::warn_falloff_nonvoid_lambda;
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D.diag_NeverFallThroughOrReturn = 0;
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D.funMode = Lambda;
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return D;
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}
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bool checkDiagnostics(DiagnosticsEngine &D, bool ReturnsVoid,
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bool HasNoReturn) const {
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if (funMode == Function) {
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return (ReturnsVoid ||
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D.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function,
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FuncLoc) == DiagnosticsEngine::Ignored)
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&& (!HasNoReturn ||
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D.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr,
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FuncLoc) == DiagnosticsEngine::Ignored)
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&& (!ReturnsVoid ||
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D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
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== DiagnosticsEngine::Ignored);
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}
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// For blocks / lambdas.
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return ReturnsVoid && !HasNoReturn
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&& ((funMode == Lambda) ||
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D.getDiagnosticLevel(diag::warn_suggest_noreturn_block, FuncLoc)
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== DiagnosticsEngine::Ignored);
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}
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};
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}
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/// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a
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/// function that should return a value. Check that we don't fall off the end
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/// of a noreturn function. We assume that functions and blocks not marked
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/// noreturn will return.
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static void CheckFallThroughForBody(Sema &S, const Decl *D, const Stmt *Body,
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const BlockExpr *blkExpr,
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const CheckFallThroughDiagnostics& CD,
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AnalysisDeclContext &AC) {
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bool ReturnsVoid = false;
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bool HasNoReturn = false;
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if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
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ReturnsVoid = FD->getResultType()->isVoidType();
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HasNoReturn = FD->hasAttr<NoReturnAttr>() ||
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FD->getType()->getAs<FunctionType>()->getNoReturnAttr();
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}
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else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
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ReturnsVoid = MD->getResultType()->isVoidType();
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HasNoReturn = MD->hasAttr<NoReturnAttr>();
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}
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else if (isa<BlockDecl>(D)) {
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QualType BlockTy = blkExpr->getType();
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if (const FunctionType *FT =
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BlockTy->getPointeeType()->getAs<FunctionType>()) {
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if (FT->getResultType()->isVoidType())
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ReturnsVoid = true;
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if (FT->getNoReturnAttr())
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HasNoReturn = true;
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}
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}
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DiagnosticsEngine &Diags = S.getDiagnostics();
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// Short circuit for compilation speed.
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if (CD.checkDiagnostics(Diags, ReturnsVoid, HasNoReturn))
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return;
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// FIXME: Function try block
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if (const CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
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switch (CheckFallThrough(AC)) {
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case UnknownFallThrough:
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break;
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case MaybeFallThrough:
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if (HasNoReturn)
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S.Diag(Compound->getRBracLoc(),
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CD.diag_MaybeFallThrough_HasNoReturn);
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else if (!ReturnsVoid)
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S.Diag(Compound->getRBracLoc(),
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CD.diag_MaybeFallThrough_ReturnsNonVoid);
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break;
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case AlwaysFallThrough:
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if (HasNoReturn)
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S.Diag(Compound->getRBracLoc(),
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CD.diag_AlwaysFallThrough_HasNoReturn);
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else if (!ReturnsVoid)
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S.Diag(Compound->getRBracLoc(),
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CD.diag_AlwaysFallThrough_ReturnsNonVoid);
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break;
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case NeverFallThroughOrReturn:
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if (ReturnsVoid && !HasNoReturn && CD.diag_NeverFallThroughOrReturn) {
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if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
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S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
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<< 0 << FD;
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} else if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
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S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn)
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<< 1 << MD;
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} else {
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S.Diag(Compound->getLBracLoc(), CD.diag_NeverFallThroughOrReturn);
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}
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}
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break;
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case NeverFallThrough:
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break;
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}
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}
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}
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//===----------------------------------------------------------------------===//
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// -Wuninitialized
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//===----------------------------------------------------------------------===//
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namespace {
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/// ContainsReference - A visitor class to search for references to
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/// a particular declaration (the needle) within any evaluated component of an
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/// expression (recursively).
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class ContainsReference : public EvaluatedExprVisitor<ContainsReference> {
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bool FoundReference;
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const DeclRefExpr *Needle;
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public:
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ContainsReference(ASTContext &Context, const DeclRefExpr *Needle)
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: EvaluatedExprVisitor<ContainsReference>(Context),
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FoundReference(false), Needle(Needle) {}
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void VisitExpr(Expr *E) {
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// Stop evaluating if we already have a reference.
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if (FoundReference)
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return;
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EvaluatedExprVisitor<ContainsReference>::VisitExpr(E);
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}
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void VisitDeclRefExpr(DeclRefExpr *E) {
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if (E == Needle)
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FoundReference = true;
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else
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EvaluatedExprVisitor<ContainsReference>::VisitDeclRefExpr(E);
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}
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bool doesContainReference() const { return FoundReference; }
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};
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}
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static bool SuggestInitializationFixit(Sema &S, const VarDecl *VD) {
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QualType VariableTy = VD->getType().getCanonicalType();
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if (VariableTy->isBlockPointerType() &&
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!VD->hasAttr<BlocksAttr>()) {
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S.Diag(VD->getLocation(), diag::note_block_var_fixit_add_initialization) << VD->getDeclName()
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<< FixItHint::CreateInsertion(VD->getLocation(), "__block ");
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return true;
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}
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// Don't issue a fixit if there is already an initializer.
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if (VD->getInit())
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return false;
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// Suggest possible initialization (if any).
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std::string Init = S.getFixItZeroInitializerForType(VariableTy);
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if (Init.empty())
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return false;
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SourceLocation Loc = S.PP.getLocForEndOfToken(VD->getLocEnd());
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S.Diag(Loc, diag::note_var_fixit_add_initialization) << VD->getDeclName()
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<< FixItHint::CreateInsertion(Loc, Init);
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return true;
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}
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/// DiagnoseUninitializedUse -- Helper function for diagnosing uses of an
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/// uninitialized variable. This manages the different forms of diagnostic
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/// emitted for particular types of uses. Returns true if the use was diagnosed
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/// as a warning. If a pariticular use is one we omit warnings for, returns
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/// false.
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static bool DiagnoseUninitializedUse(Sema &S, const VarDecl *VD,
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const Expr *E, bool isAlwaysUninit,
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bool alwaysReportSelfInit = false) {
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bool isSelfInit = false;
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if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E)) {
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if (isAlwaysUninit) {
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// Inspect the initializer of the variable declaration which is
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// being referenced prior to its initialization. We emit
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// specialized diagnostics for self-initialization, and we
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// specifically avoid warning about self references which take the
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// form of:
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//
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// int x = x;
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//
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// This is used to indicate to GCC that 'x' is intentionally left
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// uninitialized. Proven code paths which access 'x' in
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// an uninitialized state after this will still warn.
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//
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// TODO: Should we suppress maybe-uninitialized warnings for
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// variables initialized in this way?
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if (const Expr *Initializer = VD->getInit()) {
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if (!alwaysReportSelfInit && DRE == Initializer->IgnoreParenImpCasts())
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return false;
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ContainsReference CR(S.Context, DRE);
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CR.Visit(const_cast<Expr*>(Initializer));
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isSelfInit = CR.doesContainReference();
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}
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if (isSelfInit) {
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S.Diag(DRE->getLocStart(),
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diag::warn_uninit_self_reference_in_init)
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<< VD->getDeclName() << VD->getLocation() << DRE->getSourceRange();
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} else {
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|
S.Diag(DRE->getLocStart(), diag::warn_uninit_var)
|
|
<< VD->getDeclName() << DRE->getSourceRange();
|
|
}
|
|
} else {
|
|
S.Diag(DRE->getLocStart(), diag::warn_maybe_uninit_var)
|
|
<< VD->getDeclName() << DRE->getSourceRange();
|
|
}
|
|
} else {
|
|
const BlockExpr *BE = cast<BlockExpr>(E);
|
|
if (VD->getType()->isBlockPointerType() &&
|
|
!VD->hasAttr<BlocksAttr>())
|
|
S.Diag(BE->getLocStart(), diag::warn_uninit_byref_blockvar_captured_by_block)
|
|
<< VD->getDeclName();
|
|
else
|
|
S.Diag(BE->getLocStart(),
|
|
isAlwaysUninit ? diag::warn_uninit_var_captured_by_block
|
|
: diag::warn_maybe_uninit_var_captured_by_block)
|
|
<< VD->getDeclName();
|
|
}
|
|
|
|
// 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 (!isSelfInit && !SuggestInitializationFixit(S, VD))
|
|
S.Diag(VD->getLocStart(), diag::note_uninit_var_def)
|
|
<< VD->getDeclName();
|
|
|
|
return true;
|
|
}
|
|
|
|
typedef std::pair<const Expr*, bool> UninitUse;
|
|
|
|
namespace {
|
|
struct SLocSort {
|
|
bool operator()(const UninitUse &a, const UninitUse &b) {
|
|
SourceLocation aLoc = a.first->getLocStart();
|
|
SourceLocation bLoc = b.first->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 Expr *ex, const VarDecl *vd,
|
|
bool isAlwaysUninit) {
|
|
getUses(vd).first->push_back(std::make_pair(ex, isAlwaysUninit));
|
|
}
|
|
|
|
void handleSelfInit(const VarDecl *vd) {
|
|
getUses(vd).second = true;
|
|
}
|
|
|
|
void flushDiagnostics() {
|
|
if (!uses)
|
|
return;
|
|
|
|
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, 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 (DiagnoseUninitializedUse(S, vd, vi->first,
|
|
/*isAlwaysUninit=*/vi->second))
|
|
// 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->second) {
|
|
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;
|
|
}
|
|
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->getName() << getLockKindFromAccessKind(AK));
|
|
Warnings.push_back(DelayedDiag(Warning, OptionalNotes()));
|
|
}
|
|
|
|
void handleMutexNotHeld(const NamedDecl *D, ProtectedOperationKind POK,
|
|
Name LockName, LockKind LK, SourceLocation Loc) {
|
|
unsigned DiagID = 0;
|
|
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->getName() << 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;
|
|
|
|
// 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::BlockExprClass)
|
|
.setAlwaysAdd(Stmt::CStyleCastExprClass)
|
|
.setAlwaysAdd(Stmt::DeclRefExprClass)
|
|
.setAlwaysAdd(Stmt::ImplicitCastExprClass)
|
|
.setAlwaysAdd(Stmt::UnaryOperatorClass);
|
|
}
|
|
|
|
// 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_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);
|
|
}
|
|
}
|
|
}
|
|
|
|
// 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";
|
|
}
|