Enhance Sema::DiagRuntimeBehavior() to delay some diagnostics to see if the related code is reachable. This suppresses some
diagnostics that occur in unreachable code (e.g., -Warray-bound).
We only pay the cost of doing the reachability analysis when we issue one of these diagnostics.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@126290 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/AnalysisBasedWarnings.cpp b/lib/Sema/AnalysisBasedWarnings.cpp
index adfa690..6a42224 100644
--- a/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/lib/Sema/AnalysisBasedWarnings.cpp
@@ -15,6 +15,7 @@
#include "clang/Sema/AnalysisBasedWarnings.h"
#include "clang/Sema/SemaInternal.h"
+#include "clang/Sema/ScopeInfo.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/AST/DeclObjC.h"
@@ -26,6 +27,8 @@
#include "clang/Analysis/AnalysisContext.h"
#include "clang/Analysis/CFG.h"
#include "clang/Analysis/Analyses/ReachableCode.h"
+#include "clang/Analysis/Analyses/CFGReachabilityAnalysis.h"
+#include "clang/Analysis/CFGStmtMap.h"
#include "clang/Analysis/Analyses/UninitializedValuesV2.h"
#include "llvm/ADT/BitVector.h"
#include "llvm/Support/Casting.h"
@@ -478,6 +481,16 @@
Diagnostic::Ignored);
}
+static void flushDiagnostics(Sema &S, sema::FunctionScopeInfo *fscope) {
+ for (llvm::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,
@@ -491,9 +504,6 @@
// time.
Diagnostic &Diags = S.getDiagnostics();
- if (Diags.hasErrorOccurred() || Diags.hasFatalErrorOccurred())
- return;
-
// Do not do any analysis for declarations in system headers if we are
// going to just ignore them.
if (Diags.getSuppressSystemWarnings() &&
@@ -504,6 +514,12 @@
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);
@@ -512,6 +528,34 @@
AnalysisContext AC(D, 0, /*useUnoptimizedCFG=*/false, /*addehedges=*/false,
/*addImplicitDtors=*/true, /*addInitializers=*/true);
+ // Emit delayed diagnostics.
+ if (!fscope->PossiblyUnreachableDiags.empty()) {
+ bool analyzed = false;
+ if (CFGReachabilityAnalysis *cra = AC.getCFGReachablityAnalysis())
+ if (CFGStmtMap *csm = AC.getCFGStmtMap()) {
+ analyzed = true;
+ for (llvm::SmallVectorImpl<sema::PossiblyUnreachableDiag>::iterator
+ i = fscope->PossiblyUnreachableDiags.begin(),
+ e = fscope->PossiblyUnreachableDiags.end();
+ i != e; ++i) {
+ const sema::PossiblyUnreachableDiag &D = *i;
+ if (const CFGBlock *blk = csm->getBlock(D.stmt)) {
+ // Can this block be reached from the entrance?
+ if (cra->isReachable(&AC.getCFG()->getEntry(), blk))
+ S.Diag(D.Loc, D.PD);
+ }
+ else {
+ // 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 =