[cfe-commits] r99085 - in /cfe/trunk/lib/Sema: AnalysisBasedWarnings.cpp AnalysisBasedWarnings.h CMakeLists.txt Sema.h SemaChecking.cpp SemaDecl.cpp SemaExpr.cpp
Ted Kremenek
kremenek at apple.com
Sat Mar 20 14:06:03 PDT 2010
Author: kremenek
Date: Sat Mar 20 16:06:02 2010
New Revision: 99085
URL: http://llvm.org/viewvc/llvm-project?rev=99085&view=rev
Log:
Refactor CFG-based warnings in Sema to be run by a worked object called AnalysisBasedWarnings.
This object controls when the warnings are executed, allowing the client code
in Sema to selectively disable warnings as needed.
Centralizing the logic for analysis-based warnings allows us to optimize
when and how they are run.
Along the way, remove the redundant logic for the 'check fall-through' warning
for blocks; now the same logic is used for both blocks and functions.
Added:
cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
cfe/trunk/lib/Sema/AnalysisBasedWarnings.h
Modified:
cfe/trunk/lib/Sema/CMakeLists.txt
cfe/trunk/lib/Sema/Sema.h
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/lib/Sema/SemaExpr.cpp
Added: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp?rev=99085&view=auto
==============================================================================
--- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp (added)
+++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp Sat Mar 20 16:06:02 2010
@@ -0,0 +1,362 @@
+//=- 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 "Sema.h"
+#include "AnalysisBasedWarnings.h"
+#include "clang/AST/ExprObjC.h"
+#include "clang/AST/ExprCXX.h"
+#include "clang/AST/StmtObjC.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/Analysis/AnalysisContext.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Analysis/Analyses/ReachableCode.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/Support/Casting.h"
+#include <queue>
+
+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, AnalysisContext &AC) {
+ UnreachableCodeHandler UC(S);
+ reachable_code::FindUnreachableCode(AC, UC);
+}
+
+//===----------------------------------------------------------------------===//
+// Check for missing return value.
+//===----------------------------------------------------------------------===//
+
+enum ControlFlowKind { NeverFallThrough = 0, MaybeFallThrough = 1,
+ AlwaysFallThrough = 2, NeverFallThroughOrReturn = 3 };
+
+/// 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(AnalysisContext &AC) {
+ CFG *cfg = AC.getCFG();
+ if (cfg == 0)
+ // FIXME: This should be NeverFallThrough
+ return NeverFallThroughOrReturn;
+
+ // 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.
+ std::queue<CFGBlock*> workq;
+ 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;
+ for (CFGBlock::pred_iterator I=cfg->getExit().pred_begin(),
+ E = cfg->getExit().pred_end();
+ I != E;
+ ++I) {
+ CFGBlock& B = **I;
+ if (!live[B.getBlockID()])
+ continue;
+ if (B.size() == 0) {
+ if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
+ HasAbnormalEdge = true;
+ continue;
+ }
+
+ // A labeled empty statement, or the entry block...
+ HasPlainEdge = true;
+ continue;
+ }
+ Stmt *S = B[B.size()-1];
+ if (isa<ReturnStmt>(S)) {
+ HasLiveReturn = true;
+ continue;
+ }
+ if (isa<ObjCAtThrowStmt>(S)) {
+ HasFakeEdge = true;
+ continue;
+ }
+ if (isa<CXXThrowExpr>(S)) {
+ HasFakeEdge = true;
+ continue;
+ }
+ if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) {
+ if (AS->isMSAsm()) {
+ HasFakeEdge = true;
+ HasLiveReturn = true;
+ continue;
+ }
+ }
+ if (isa<CXXTryStmt>(S)) {
+ HasAbnormalEdge = true;
+ continue;
+ }
+
+ bool NoReturnEdge = false;
+ if (CallExpr *C = dyn_cast<CallExpr>(S)) {
+ if (B.succ_begin()[0] != &cfg->getExit()) {
+ HasAbnormalEdge = true;
+ continue;
+ }
+ Expr *CEE = C->getCallee()->IgnoreParenCasts();
+ if (CEE->getType().getNoReturnAttr()) {
+ NoReturnEdge = true;
+ HasFakeEdge = true;
+ } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE)) {
+ ValueDecl *VD = DRE->getDecl();
+ if (VD->hasAttr<NoReturnAttr>()) {
+ NoReturnEdge = true;
+ HasFakeEdge = true;
+ }
+ }
+ }
+ // FIXME: Add noreturn message sends.
+ if (NoReturnEdge == false)
+ 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;
+}
+
+struct CheckFallThroughDiagnostics {
+ unsigned diag_MaybeFallThrough_HasNoReturn;
+ unsigned diag_MaybeFallThrough_ReturnsNonVoid;
+ unsigned diag_AlwaysFallThrough_HasNoReturn;
+ unsigned diag_AlwaysFallThrough_ReturnsNonVoid;
+ unsigned diag_NeverFallThroughOrReturn;
+ bool funMode;
+
+ static CheckFallThroughDiagnostics MakeForFunction() {
+ CheckFallThroughDiagnostics D;
+ 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;
+ D.diag_NeverFallThroughOrReturn =
+ diag::warn_suggest_noreturn_function;
+ D.funMode = true;
+ 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 = false;
+ return D;
+ }
+
+ bool checkDiagnostics(Diagnostic &D, bool ReturnsVoid,
+ bool HasNoReturn) const {
+ if (funMode) {
+ return (D.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function)
+ == Diagnostic::Ignored || ReturnsVoid)
+ && (D.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr)
+ == Diagnostic::Ignored || !HasNoReturn)
+ && (D.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
+ == Diagnostic::Ignored || !ReturnsVoid);
+ }
+
+ // For blocks.
+ return ReturnsVoid && !HasNoReturn
+ && (D.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
+ == Diagnostic::Ignored || !ReturnsVoid);
+ }
+};
+
+/// 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,
+ QualType BlockTy,
+ const CheckFallThroughDiagnostics& CD,
+ AnalysisContext &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)) {
+ if (const FunctionType *FT =
+ BlockTy->getPointeeType()->getAs<FunctionType>()) {
+ if (FT->getResultType()->isVoidType())
+ ReturnsVoid = true;
+ if (FT->getNoReturnAttr())
+ HasNoReturn = true;
+ }
+ }
+
+ Diagnostic &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 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)
+ S.Diag(Compound->getLBracLoc(),
+ CD.diag_NeverFallThroughOrReturn);
+ break;
+ case NeverFallThrough:
+ break;
+ }
+ }
+}
+
+//===----------------------------------------------------------------------===//
+// AnalysisBasedWarnings - Worker object used by Sema to execute analysis-based
+// warnings on a function, method, or block.
+//===----------------------------------------------------------------------===//
+
+clang::sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s) : S(s) {
+ Diagnostic &D = S.getDiagnostics();
+
+ enableCheckFallThrough = 1;
+
+ enableCheckUnreachable = (unsigned)
+ (D.getDiagnosticLevel(diag::warn_unreachable) != Diagnostic::Ignored);
+}
+
+void clang::sema::AnalysisBasedWarnings::IssueWarnings(const Decl *D,
+ QualType BlockTy) {
+
+ assert(BlockTy.isNull() || isa<BlockDecl>(D));
+
+ // 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.
+ if (S.getDiagnostics().hasErrorOccurred())
+ return;
+
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+ // For function templates, class templates and member function templates
+ // we'll do the analysis at instantiation time.
+ if (FD->isDependentContext())
+ return;
+ }
+
+ const Stmt *Body = D->getBody();
+ assert(Body);
+
+ // 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.
+ AnalysisContext AC(D, false);
+
+ // Warning: check missing 'return'
+ if (enableCheckFallThrough) {
+ const CheckFallThroughDiagnostics &CD =
+ (isa<BlockDecl>(D) ? CheckFallThroughDiagnostics::MakeForBlock()
+ : CheckFallThroughDiagnostics::MakeForFunction());
+ CheckFallThroughForBody(S, D, Body, BlockTy, CD, AC);
+ }
+
+ // Warning: check for unreachable code
+ if (enableCheckUnreachable)
+ CheckUnreachable(S, AC);
+}
Added: cfe/trunk/lib/Sema/AnalysisBasedWarnings.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.h?rev=99085&view=auto
==============================================================================
--- cfe/trunk/lib/Sema/AnalysisBasedWarnings.h (added)
+++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.h Sat Mar 20 16:06:02 2010
@@ -0,0 +1,35 @@
+//=- AnalysisBasedWarnings.h - 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 AnalysisBasedWarnings, a worker object used by Sema
+// that issues warnings based on dataflow-analysis.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_ANALYSIS_WARNINGS_H
+#define LLVM_CLANG_SEMA_ANALYSIS_WARNINGS_H
+
+namespace clang { namespace sema {
+
+class AnalysisBasedWarnings {
+ Sema &S;
+ // The warnings to run.
+ unsigned enableCheckFallThrough : 1;
+ unsigned enableCheckUnreachable : 1;
+
+public:
+
+ AnalysisBasedWarnings(Sema &s);
+ void IssueWarnings(const Decl *D, QualType BlockTy = QualType());
+
+ void disableCheckFallThrough() { enableCheckFallThrough = 0; }
+};
+
+}} // end namespace clang::sema
+
+#endif
Modified: cfe/trunk/lib/Sema/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/CMakeLists.txt?rev=99085&r1=99084&r2=99085&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/CMakeLists.txt (original)
+++ cfe/trunk/lib/Sema/CMakeLists.txt Sat Mar 20 16:06:02 2010
@@ -1,6 +1,7 @@
set(LLVM_NO_RTTI 1)
add_clang_library(clangSema
+ AnalysisBasedWarnings.cpp
CodeCompleteConsumer.cpp
IdentifierResolver.cpp
JumpDiagnostics.cpp
Modified: cfe/trunk/lib/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/Sema.h?rev=99085&r1=99084&r2=99085&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/Sema.h (original)
+++ cfe/trunk/lib/Sema/Sema.h Sat Mar 20 16:06:02 2010
@@ -42,7 +42,6 @@
}
namespace clang {
- class AnalysisContext;
class ASTContext;
class ASTConsumer;
class CodeCompleteConsumer;
@@ -1296,9 +1295,6 @@
OwningExprResult BuildOverloadedArrowExpr(Scope *S, ExprArg Base,
SourceLocation OpLoc);
- /// CheckUnreachable - Check for unreachable code.
- void CheckUnreachable(AnalysisContext &);
-
/// CheckCallReturnType - Checks that a call expression's return type is
/// complete. Returns true on failure. The location passed in is the location
/// that best represents the call.
@@ -1306,15 +1302,9 @@
CallExpr *CE, FunctionDecl *FD);
/// Helpers for dealing with blocks and functions.
- void CheckFallThroughForFunctionDef(Decl *D, Stmt *Body, AnalysisContext &);
- void CheckFallThroughForBlock(QualType BlockTy, Stmt *, AnalysisContext &);
bool CheckParmsForFunctionDef(FunctionDecl *FD);
void CheckCXXDefaultArguments(FunctionDecl *FD);
void CheckExtraCXXDefaultArguments(Declarator &D);
- enum ControlFlowKind { NeverFallThrough = 0, MaybeFallThrough = 1,
- AlwaysFallThrough = 2, NeverFallThroughOrReturn = 3 };
- ControlFlowKind CheckFallThrough(AnalysisContext &);
-
Scope *getNonFieldDeclScope(Scope *S);
/// \name Name lookup
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=99085&r1=99084&r2=99085&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Sat Mar 20 16:06:02 2010
@@ -13,9 +13,6 @@
//===----------------------------------------------------------------------===//
#include "Sema.h"
-#include "clang/Analysis/AnalysisContext.h"
-#include "clang/Analysis/CFG.h"
-#include "clang/Analysis/Analyses/ReachableCode.h"
#include "clang/Analysis/Analyses/PrintfFormatString.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
@@ -30,7 +27,6 @@
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/STLExtras.h"
#include <limits>
-#include <queue>
using namespace clang;
/// getLocationOfStringLiteralByte - Return a source location that points to the
@@ -2224,276 +2220,6 @@
return;
}
-
-
-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.
-void Sema::CheckUnreachable(AnalysisContext &AC) {
- // We avoid checking when there are errors, as the CFG won't faithfully match
- // the user's code.
- if (getDiagnostics().hasErrorOccurred() ||
- Diags.getDiagnosticLevel(diag::warn_unreachable) == Diagnostic::Ignored)
- return;
-
- UnreachableCodeHandler UC(this);
- reachable_code::FindUnreachableCode(AC, UC);
-}
-
-/// 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.
-Sema::ControlFlowKind Sema::CheckFallThrough(AnalysisContext &AC) {
- CFG *cfg = AC.getCFG();
- if (cfg == 0)
- // FIXME: This should be NeverFallThrough
- return NeverFallThroughOrReturn;
-
- // 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.
- std::queue<CFGBlock*> workq;
- 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;
- for (CFGBlock::pred_iterator I=cfg->getExit().pred_begin(),
- E = cfg->getExit().pred_end();
- I != E;
- ++I) {
- CFGBlock& B = **I;
- if (!live[B.getBlockID()])
- continue;
- if (B.size() == 0) {
- if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) {
- HasAbnormalEdge = true;
- continue;
- }
-
- // A labeled empty statement, or the entry block...
- HasPlainEdge = true;
- continue;
- }
- Stmt *S = B[B.size()-1];
- if (isa<ReturnStmt>(S)) {
- HasLiveReturn = true;
- continue;
- }
- if (isa<ObjCAtThrowStmt>(S)) {
- HasFakeEdge = true;
- continue;
- }
- if (isa<CXXThrowExpr>(S)) {
- HasFakeEdge = true;
- continue;
- }
- if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) {
- if (AS->isMSAsm()) {
- HasFakeEdge = true;
- HasLiveReturn = true;
- continue;
- }
- }
- if (isa<CXXTryStmt>(S)) {
- HasAbnormalEdge = true;
- continue;
- }
-
- bool NoReturnEdge = false;
- if (CallExpr *C = dyn_cast<CallExpr>(S)) {
- if (B.succ_begin()[0] != &cfg->getExit()) {
- HasAbnormalEdge = true;
- continue;
- }
- Expr *CEE = C->getCallee()->IgnoreParenCasts();
- if (CEE->getType().getNoReturnAttr()) {
- NoReturnEdge = true;
- HasFakeEdge = true;
- } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE)) {
- ValueDecl *VD = DRE->getDecl();
- if (VD->hasAttr<NoReturnAttr>()) {
- NoReturnEdge = true;
- HasFakeEdge = true;
- }
- }
- }
- // FIXME: Add noreturn message sends.
- if (NoReturnEdge == false)
- 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;
-}
-
-/// 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.
-void Sema::CheckFallThroughForFunctionDef(Decl *D, Stmt *Body,
- AnalysisContext &AC) {
- // FIXME: Would be nice if we had a better way to control cascading errors,
- // but for now, avoid them. The problem is that when Parse sees:
- // int foo() { return a; }
- // The return is eaten and the Sema code sees just:
- // int foo() { }
- // which this code would then warn about.
- if (getDiagnostics().hasErrorOccurred())
- return;
-
- bool ReturnsVoid = false;
- bool HasNoReturn = false;
-
- if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
- // For function templates, class templates and member function templates
- // we'll do the analysis at instantiation time.
- if (FD->isDependentContext())
- return;
-
- ReturnsVoid = FD->getResultType()->isVoidType();
- HasNoReturn = FD->hasAttr<NoReturnAttr>() ||
- FD->getType()->getAs<FunctionType>()->getNoReturnAttr();
-
- } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
- ReturnsVoid = MD->getResultType()->isVoidType();
- HasNoReturn = MD->hasAttr<NoReturnAttr>();
- }
-
- // Short circuit for compilation speed.
- if ((Diags.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function)
- == Diagnostic::Ignored || ReturnsVoid)
- && (Diags.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr)
- == Diagnostic::Ignored || !HasNoReturn)
- && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
- == Diagnostic::Ignored || !ReturnsVoid))
- return;
- // FIXME: Function try block
- if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
- switch (CheckFallThrough(AC)) {
- case MaybeFallThrough:
- if (HasNoReturn)
- Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function);
- else if (!ReturnsVoid)
- Diag(Compound->getRBracLoc(),diag::warn_maybe_falloff_nonvoid_function);
- break;
- case AlwaysFallThrough:
- if (HasNoReturn)
- Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function);
- else if (!ReturnsVoid)
- Diag(Compound->getRBracLoc(), diag::warn_falloff_nonvoid_function);
- break;
- case NeverFallThroughOrReturn:
- if (ReturnsVoid && !HasNoReturn)
- Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_function);
- break;
- case NeverFallThrough:
- break;
- }
- }
-}
-
-/// CheckFallThroughForBlock - Check that we don't fall off the end of a block
-/// that should return a value. Check that we don't fall off the end of a
-/// noreturn block. We assume that functions and blocks not marked noreturn
-/// will return.
-void Sema::CheckFallThroughForBlock(QualType BlockTy, Stmt *Body,
- AnalysisContext &AC) {
- // FIXME: Would be nice if we had a better way to control cascading errors,
- // but for now, avoid them. The problem is that when Parse sees:
- // int foo() { return a; }
- // The return is eaten and the Sema code sees just:
- // int foo() { }
- // which this code would then warn about.
- if (getDiagnostics().hasErrorOccurred())
- return;
- bool ReturnsVoid = false;
- bool HasNoReturn = false;
- if (const FunctionType *FT =BlockTy->getPointeeType()->getAs<FunctionType>()){
- if (FT->getResultType()->isVoidType())
- ReturnsVoid = true;
- if (FT->getNoReturnAttr())
- HasNoReturn = true;
- }
-
- // Short circuit for compilation speed.
- if (ReturnsVoid
- && !HasNoReturn
- && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block)
- == Diagnostic::Ignored || !ReturnsVoid))
- return;
- // FIXME: Funtion try block
- if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) {
- switch (CheckFallThrough(AC)) {
- case MaybeFallThrough:
- if (HasNoReturn)
- Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
- else if (!ReturnsVoid)
- Diag(Compound->getRBracLoc(), diag::err_maybe_falloff_nonvoid_block);
- break;
- case AlwaysFallThrough:
- if (HasNoReturn)
- Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr);
- else if (!ReturnsVoid)
- Diag(Compound->getRBracLoc(), diag::err_falloff_nonvoid_block);
- break;
- case NeverFallThroughOrReturn:
- if (ReturnsVoid)
- Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_block);
- break;
- case NeverFallThrough:
- break;
- }
- }
-}
-
/// CheckParmsForFunctionDef - Check that the parameters of the given
/// function are appropriate for the definition of a function. This
/// takes care of any checks that cannot be performed on the
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=99085&r1=99084&r2=99085&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Sat Mar 20 16:06:02 2010
@@ -14,7 +14,7 @@
#include "Sema.h"
#include "SemaInit.h"
#include "Lookup.h"
-#include "clang/Analysis/AnalysisContext.h"
+#include "AnalysisBasedWarnings.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
@@ -4259,9 +4259,6 @@
Decl *dcl = D.getAs<Decl>();
Stmt *Body = BodyArg.takeAs<Stmt>();
- // 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.
- AnalysisContext AC(dcl, false);
FunctionDecl *FD = 0;
FunctionTemplateDecl *FunTmpl = dyn_cast_or_null<FunctionTemplateDecl>(dcl);
if (FunTmpl)
@@ -4269,14 +4266,16 @@
else
FD = dyn_cast_or_null<FunctionDecl>(dcl);
+ sema::AnalysisBasedWarnings W(*this);
+
if (FD) {
FD->setBody(Body);
- if (FD->isMain())
+ if (FD->isMain()) {
// C and C++ allow for main to automagically return 0.
// Implements C++ [basic.start.main]p5 and C99 5.1.2.2.3.
FD->setHasImplicitReturnZero(true);
- else
- CheckFallThroughForFunctionDef(FD, Body, AC);
+ W.disableCheckFallThrough();
+ }
if (!FD->isInvalidDecl())
DiagnoseUnusedParameters(FD->param_begin(), FD->param_end());
@@ -4288,9 +4287,7 @@
} else if (ObjCMethodDecl *MD = dyn_cast_or_null<ObjCMethodDecl>(dcl)) {
assert(MD == getCurMethodDecl() && "Method parsing confused");
MD->setBody(Body);
- CheckFallThroughForFunctionDef(MD, Body, AC);
MD->setEndLoc(Body->getLocEnd());
-
if (!MD->isInvalidDecl())
DiagnoseUnusedParameters(MD->param_begin(), MD->param_end());
} else {
@@ -4343,16 +4340,14 @@
}
if (Body) {
- CheckUnreachable(AC);
-
// C++ constructors that have function-try-blocks can't have return
// statements in the handlers of that block. (C++ [except.handle]p14)
// Verify this.
if (FD && isa<CXXConstructorDecl>(FD) && isa<CXXTryStmt>(Body))
DiagnoseReturnInConstructorExceptionHandler(cast<CXXTryStmt>(Body));
- // Verify that that gotos and switch cases don't jump into scopes illegally.
- // Verify that that gotos and switch cases don't jump into scopes illegally.
+ // Verify that that gotos and switch cases don't jump into scopes illegally.
+ // Verify that that gotos and switch cases don't jump into scopes illegally.
if (FunctionNeedsScopeChecking() && !hasAnyErrorsInThisFunction())
DiagnoseInvalidJumps(Body);
@@ -4365,7 +4360,20 @@
// deletion in some later function.
if (PP.getDiagnostics().hasErrorOccurred())
ExprTemporaries.clear();
-
+ else if (!isa<FunctionTemplateDecl>(dcl)) {
+ // Since the body is valid, issue any analysis-based warnings that are
+ // enabled.
+ QualType ResultType;
+ if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(dcl)) {
+ ResultType = FD->getResultType();
+ }
+ else {
+ ObjCMethodDecl *MD = cast<ObjCMethodDecl>(dcl);
+ ResultType = MD->getResultType();
+ }
+ W.IssueWarnings(dcl);
+ }
+
assert(ExprTemporaries.empty() && "Leftover temporaries in function");
}
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=99085&r1=99084&r2=99085&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Sat Mar 20 16:06:02 2010
@@ -14,7 +14,7 @@
#include "Sema.h"
#include "SemaInit.h"
#include "Lookup.h"
-#include "clang/Analysis/AnalysisContext.h"
+#include "AnalysisBasedWarnings.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
@@ -7003,9 +7003,10 @@
return ExprError();
}
- AnalysisContext AC(BSI->TheDecl);
- CheckFallThroughForBlock(BlockTy, BSI->TheDecl->getBody(), AC);
- CheckUnreachable(AC);
+ // Issue any analysis-based warnings.
+ sema::AnalysisBasedWarnings W(*this);
+ W.IssueWarnings(BSI->TheDecl, BlockTy);
+
Expr *Result = new (Context) BlockExpr(BSI->TheDecl, BlockTy,
BSI->hasBlockDeclRefExprs);
PopFunctionOrBlockScope();
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