[cfe-commits] r94067 - in /cfe/trunk/lib/Sema: SemaChecking.cpp SemaDecl.cpp
Mike Stump
mrs at apple.com
Wed Jan 20 19:59:47 PST 2010
Author: mrs
Date: Wed Jan 20 21:59:47 2010
New Revision: 94067
URL: http://llvm.org/viewvc/llvm-project?rev=94067&view=rev
Log:
Move some recent checking code into SemaChecking instead.
Modified:
cfe/trunk/lib/Sema/SemaChecking.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=94067&r1=94066&r2=94067&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Wed Jan 20 21:59:47 2010
@@ -13,14 +13,22 @@
//===----------------------------------------------------------------------===//
#include "Sema.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Analysis/PathSensitive/AnalysisContext.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/ExprObjC.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/StmtCXX.h"
+#include "clang/AST/StmtObjC.h"
#include "clang/Lex/LiteralSupport.h"
#include "clang/Lex/Preprocessor.h"
+#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
@@ -2029,3 +2037,425 @@
return;
}
+// MarkLive - Mark all the blocks reachable from e as live. Returns the total
+// number of blocks just marked live.
+static unsigned MarkLive(CFGBlock *e, llvm::BitVector &live) {
+ unsigned count = 0;
+ std::queue<CFGBlock*> workq;
+ // Prep work queue
+ live.set(e->getBlockID());
+ ++count;
+ workq.push(e);
+ // Solve
+ while (!workq.empty()) {
+ CFGBlock *item = workq.front();
+ workq.pop();
+ for (CFGBlock::succ_iterator I=item->succ_begin(),
+ E=item->succ_end();
+ I != E;
+ ++I) {
+ if ((*I) && !live[(*I)->getBlockID()]) {
+ live.set((*I)->getBlockID());
+ ++count;
+ workq.push(*I);
+ }
+ }
+ }
+ return count;
+}
+
+static SourceLocation GetUnreachableLoc(CFGBlock &b) {
+ Stmt *S;
+ if (!b.empty())
+ S = b[0].getStmt();
+ else if (b.getTerminator())
+ S = b.getTerminator();
+ else
+ return SourceLocation();
+
+ switch (S->getStmtClass()) {
+ case Expr::BinaryOperatorClass: {
+ if (b.size() < 2) {
+ CFGBlock *n = &b;
+ while (1) {
+ if (n->getTerminator())
+ return n->getTerminator()->getLocStart();
+ if (n->succ_size() != 1)
+ return SourceLocation();
+ n = n[0].succ_begin()[0];
+ if (n->pred_size() != 1)
+ return SourceLocation();
+ if (!n->empty())
+ return n[0][0].getStmt()->getLocStart();
+ }
+ }
+ return b[1].getStmt()->getLocStart();
+ }
+ default: ;
+ }
+ return S->getLocStart();
+}
+
+static SourceLocation MarkLiveTop(CFGBlock *e, llvm::BitVector &live,
+ SourceManager &SM) {
+ std::queue<CFGBlock*> workq;
+ // Prep work queue
+ workq.push(e);
+ SourceLocation top = GetUnreachableLoc(*e);
+ bool FromMainFile = false;
+ bool FromSystemHeader = false;
+ bool TopValid = false;
+ if (top.isValid()) {
+ FromMainFile = SM.isFromMainFile(top);
+ FromSystemHeader = SM.isInSystemHeader(top);
+ TopValid = true;
+ }
+ // Solve
+ while (!workq.empty()) {
+ CFGBlock *item = workq.front();
+ workq.pop();
+ SourceLocation c = GetUnreachableLoc(*item);
+ if (c.isValid()
+ && (!TopValid
+ || (SM.isFromMainFile(c) && !FromMainFile)
+ || (FromSystemHeader && !SM.isInSystemHeader(c))
+ || SM.isBeforeInTranslationUnit(c, top))) {
+ top = c;
+ FromMainFile = SM.isFromMainFile(top);
+ FromSystemHeader = SM.isInSystemHeader(top);
+ }
+ live.set(item->getBlockID());
+ for (CFGBlock::succ_iterator I=item->succ_begin(),
+ E=item->succ_end();
+ I != E;
+ ++I) {
+ if ((*I) && !live[(*I)->getBlockID()]) {
+ live.set((*I)->getBlockID());
+ workq.push(*I);
+ }
+ }
+ }
+ return top;
+}
+
+static int LineCmp(const void *p1, const void *p2) {
+ SourceLocation *Line1 = (SourceLocation *)p1;
+ SourceLocation *Line2 = (SourceLocation *)p2;
+ return !(*Line1 < *Line2);
+}
+
+/// CheckUnreachable - Check for unreachable code.
+void Sema::CheckUnreachable(AnalysisContext &AC) {
+ unsigned count;
+ // We avoid checking when there are errors, as the CFG won't faithfully match
+ // the user's code.
+ if (getDiagnostics().hasErrorOccurred())
+ return;
+ if (Diags.getDiagnosticLevel(diag::warn_unreachable) == Diagnostic::Ignored)
+ return;
+
+ CFG *cfg = AC.getCFG();
+ if (cfg == 0)
+ return;
+
+ llvm::BitVector live(cfg->getNumBlockIDs());
+ // Mark all live things first.
+ count = MarkLive(&cfg->getEntry(), live);
+
+ if (count == cfg->getNumBlockIDs())
+ // If there are no dead blocks, we're done.
+ return;
+
+ llvm::SmallVector<SourceLocation, 24> lines;
+ // First, give warnings for blocks with no predecessors, as they
+ // can't be part of a loop.
+ 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()) {
+ SourceLocation c = GetUnreachableLoc(b);
+ if (!c.isValid()) {
+ // Blocks without a location can't produce a warning, so don't mark
+ // reachable blocks from here as live.
+ live.set(b.getBlockID());
+ ++count;
+ continue;
+ }
+ lines.push_back(c);
+ // Avoid excessive errors by marking everything reachable from here
+ count += MarkLive(&b, live);
+ }
+ }
+ }
+
+ if (count < cfg->getNumBlockIDs()) {
+ // And then give warnings for the tops of loops.
+ for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
+ CFGBlock &b = **I;
+ if (!live[b.getBlockID()])
+ // Avoid excessive errors by marking everything reachable from here
+ lines.push_back(MarkLiveTop(&b, live, Context.getSourceManager()));
+ }
+ }
+
+ llvm::array_pod_sort(lines.begin(), lines.end(), LineCmp);
+ for (llvm::SmallVector<SourceLocation, 24>::iterator I = lines.begin(),
+ E = lines.end();
+ I != E;
+ ++I)
+ if (I->isValid())
+ Diag(*I, diag::warn_unreachable);
+}
+
+/// 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 to dead code paths to
+ // confuse us, so we mark all live things first.
+ std::queue<CFGBlock*> workq;
+ llvm::BitVector live(cfg->getNumBlockIDs());
+ MarkLive(&cfg->getEntry(), live);
+
+ // 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) {
+ // 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)) {
+ // If the result type of the function is a dependent type, we don't know
+ // whether it will be void or not, so don't
+ if (FD->getResultType()->isDependentType())
+ return;
+ if (FD->getResultType()->isVoidType())
+ ReturnsVoid = true;
+ if (FD->hasAttr<NoReturnAttr>())
+ HasNoReturn = true;
+ } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
+ if (MD->getResultType()->isVoidType())
+ ReturnsVoid = true;
+ if (MD->hasAttr<NoReturnAttr>())
+ HasNoReturn = true;
+ }
+
+ // 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
+/// declaration itself, e.g., that the types of each of the function
+/// parameters are complete.
+bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) {
+ bool HasInvalidParm = false;
+ for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) {
+ ParmVarDecl *Param = FD->getParamDecl(p);
+
+ // C99 6.7.5.3p4: the parameters in a parameter type list in a
+ // function declarator that is part of a function definition of
+ // that function shall not have incomplete type.
+ //
+ // This is also C++ [dcl.fct]p6.
+ if (!Param->isInvalidDecl() &&
+ RequireCompleteType(Param->getLocation(), Param->getType(),
+ diag::err_typecheck_decl_incomplete_type)) {
+ Param->setInvalidDecl();
+ HasInvalidParm = true;
+ }
+
+ // C99 6.9.1p5: If the declarator includes a parameter type list, the
+ // declaration of each parameter shall include an identifier.
+ if (Param->getIdentifier() == 0 &&
+ !Param->isImplicit() &&
+ !getLangOptions().CPlusPlus)
+ Diag(Param->getLocation(), diag::err_parameter_name_omitted);
+ }
+
+ return HasInvalidParm;
+}
Modified: cfe/trunk/lib/Sema/SemaDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDecl.cpp?rev=94067&r1=94066&r2=94067&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDecl.cpp Wed Jan 20 21:59:47 2010
@@ -18,13 +18,10 @@
#include "clang/AST/APValue.h"
#include "clang/AST/ASTConsumer.h"
#include "clang/AST/ASTContext.h"
-#include "clang/Analysis/CFG.h"
#include "clang/AST/CXXInheritance.h"
-#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/StmtCXX.h"
-#include "clang/AST/StmtObjC.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "clang/Parse/Template.h"
@@ -34,13 +31,10 @@
// FIXME: layering (ideally, Sema shouldn't be dependent on Lex API's)
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/HeaderSearch.h"
-#include "llvm/ADT/BitVector.h"
-#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/Triple.h"
#include <algorithm>
#include <cstring>
#include <functional>
-#include <queue>
using namespace clang;
/// getDeclName - Return a pretty name for the specified decl if possible, or
@@ -1310,429 +1304,6 @@
New->setAccess(Old->getAccess());
}
-// MarkLive - Mark all the blocks reachable from e as live. Returns the total
-// number of blocks just marked live.
-static unsigned MarkLive(CFGBlock *e, llvm::BitVector &live) {
- unsigned count = 0;
- std::queue<CFGBlock*> workq;
- // Prep work queue
- live.set(e->getBlockID());
- ++count;
- workq.push(e);
- // Solve
- while (!workq.empty()) {
- CFGBlock *item = workq.front();
- workq.pop();
- for (CFGBlock::succ_iterator I=item->succ_begin(),
- E=item->succ_end();
- I != E;
- ++I) {
- if ((*I) && !live[(*I)->getBlockID()]) {
- live.set((*I)->getBlockID());
- ++count;
- workq.push(*I);
- }
- }
- }
- return count;
-}
-
-static SourceLocation GetUnreachableLoc(CFGBlock &b) {
- Stmt *S;
- if (!b.empty())
- S = b[0].getStmt();
- else if (b.getTerminator())
- S = b.getTerminator();
- else
- return SourceLocation();
-
- switch (S->getStmtClass()) {
- case Expr::BinaryOperatorClass: {
- if (b.size() < 2) {
- CFGBlock *n = &b;
- while (1) {
- if (n->getTerminator())
- return n->getTerminator()->getLocStart();
- if (n->succ_size() != 1)
- return SourceLocation();
- n = n[0].succ_begin()[0];
- if (n->pred_size() != 1)
- return SourceLocation();
- if (!n->empty())
- return n[0][0].getStmt()->getLocStart();
- }
- }
- return b[1].getStmt()->getLocStart();
- }
- default: ;
- }
- return S->getLocStart();
-}
-
-static SourceLocation MarkLiveTop(CFGBlock *e, llvm::BitVector &live,
- SourceManager &SM) {
- std::queue<CFGBlock*> workq;
- // Prep work queue
- workq.push(e);
- SourceLocation top = GetUnreachableLoc(*e);
- bool FromMainFile = false;
- bool FromSystemHeader = false;
- bool TopValid = false;
- if (top.isValid()) {
- FromMainFile = SM.isFromMainFile(top);
- FromSystemHeader = SM.isInSystemHeader(top);
- TopValid = true;
- }
- // Solve
- while (!workq.empty()) {
- CFGBlock *item = workq.front();
- workq.pop();
- SourceLocation c = GetUnreachableLoc(*item);
- if (c.isValid()
- && (!TopValid
- || (SM.isFromMainFile(c) && !FromMainFile)
- || (FromSystemHeader && !SM.isInSystemHeader(c))
- || SM.isBeforeInTranslationUnit(c, top))) {
- top = c;
- FromMainFile = SM.isFromMainFile(top);
- FromSystemHeader = SM.isInSystemHeader(top);
- }
- live.set(item->getBlockID());
- for (CFGBlock::succ_iterator I=item->succ_begin(),
- E=item->succ_end();
- I != E;
- ++I) {
- if ((*I) && !live[(*I)->getBlockID()]) {
- live.set((*I)->getBlockID());
- workq.push(*I);
- }
- }
- }
- return top;
-}
-
-static int LineCmp(const void *p1, const void *p2) {
- SourceLocation *Line1 = (SourceLocation *)p1;
- SourceLocation *Line2 = (SourceLocation *)p2;
- return !(*Line1 < *Line2);
-}
-
-/// CheckUnreachable - Check for unreachable code.
-void Sema::CheckUnreachable(AnalysisContext &AC) {
- unsigned count;
- // We avoid checking when there are errors, as the CFG won't faithfully match
- // the user's code.
- if (getDiagnostics().hasErrorOccurred())
- return;
- if (Diags.getDiagnosticLevel(diag::warn_unreachable) == Diagnostic::Ignored)
- return;
-
- CFG *cfg = AC.getCFG();
- if (cfg == 0)
- return;
-
- llvm::BitVector live(cfg->getNumBlockIDs());
- // Mark all live things first.
- count = MarkLive(&cfg->getEntry(), live);
-
- if (count == cfg->getNumBlockIDs())
- // If there are no dead blocks, we're done.
- return;
-
- llvm::SmallVector<SourceLocation, 24> lines;
- // First, give warnings for blocks with no predecessors, as they
- // can't be part of a loop.
- 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()) {
- SourceLocation c = GetUnreachableLoc(b);
- if (!c.isValid()) {
- // Blocks without a location can't produce a warning, so don't mark
- // reachable blocks from here as live.
- live.set(b.getBlockID());
- ++count;
- continue;
- }
- lines.push_back(c);
- // Avoid excessive errors by marking everything reachable from here
- count += MarkLive(&b, live);
- }
- }
- }
-
- if (count < cfg->getNumBlockIDs()) {
- // And then give warnings for the tops of loops.
- for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) {
- CFGBlock &b = **I;
- if (!live[b.getBlockID()])
- // Avoid excessive errors by marking everything reachable from here
- lines.push_back(MarkLiveTop(&b, live, Context.getSourceManager()));
- }
- }
-
- llvm::array_pod_sort(lines.begin(), lines.end(), LineCmp);
- for (llvm::SmallVector<SourceLocation, 24>::iterator I = lines.begin(),
- E = lines.end();
- I != E;
- ++I)
- if (I->isValid())
- Diag(*I, diag::warn_unreachable);
-}
-
-/// 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 to dead code paths to
- // confuse us, so we mark all live things first.
- std::queue<CFGBlock*> workq;
- llvm::BitVector live(cfg->getNumBlockIDs());
- MarkLive(&cfg->getEntry(), live);
-
- // 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) {
- // 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)) {
- // If the result type of the function is a dependent type, we don't know
- // whether it will be void or not, so don't
- if (FD->getResultType()->isDependentType())
- return;
- if (FD->getResultType()->isVoidType())
- ReturnsVoid = true;
- if (FD->hasAttr<NoReturnAttr>())
- HasNoReturn = true;
- } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
- if (MD->getResultType()->isVoidType())
- ReturnsVoid = true;
- if (MD->hasAttr<NoReturnAttr>())
- HasNoReturn = true;
- }
-
- // 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
-/// declaration itself, e.g., that the types of each of the function
-/// parameters are complete.
-bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) {
- bool HasInvalidParm = false;
- for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) {
- ParmVarDecl *Param = FD->getParamDecl(p);
-
- // C99 6.7.5.3p4: the parameters in a parameter type list in a
- // function declarator that is part of a function definition of
- // that function shall not have incomplete type.
- //
- // This is also C++ [dcl.fct]p6.
- if (!Param->isInvalidDecl() &&
- RequireCompleteType(Param->getLocation(), Param->getType(),
- diag::err_typecheck_decl_incomplete_type)) {
- Param->setInvalidDecl();
- HasInvalidParm = true;
- }
-
- // C99 6.9.1p5: If the declarator includes a parameter type list, the
- // declaration of each parameter shall include an identifier.
- if (Param->getIdentifier() == 0 &&
- !Param->isImplicit() &&
- !getLangOptions().CPlusPlus)
- Diag(Param->getLocation(), diag::err_parameter_name_omitted);
- }
-
- return HasInvalidParm;
-}
-
/// ParsedFreeStandingDeclSpec - This method is invoked when a declspec with
/// no declarator (e.g. "struct foo;") is parsed.
Sema::DeclPtrTy Sema::ParsedFreeStandingDeclSpec(Scope *S, DeclSpec &DS) {
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