From 5e04bdde8e74d991feffe9cf95d731f7e473dbb7 Mon Sep 17 00:00:00 2001 From: Jordy Rose Date: Tue, 27 Jul 2010 03:39:53 +0000 Subject: [PATCH] Don't warn about unreachable code if the block starts with __builtin_unreachable(). The next step is to warn if a block labeled unreachable is, in fact, reachable. Somewhat related to PR810. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@109487 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Checker/UnreachableCodeChecker.cpp | 17 ++++++++++++++++- test/Analysis/unreachable-code-path.c | 6 ++++++ 2 files changed, 22 insertions(+), 1 deletion(-) diff --git a/lib/Checker/UnreachableCodeChecker.cpp b/lib/Checker/UnreachableCodeChecker.cpp index 0af49a33fb..9ee3d02d26 100644 --- a/lib/Checker/UnreachableCodeChecker.cpp +++ b/lib/Checker/UnreachableCodeChecker.cpp @@ -10,7 +10,7 @@ // path-sensitive analysis. We mark any path visited, and then walk the CFG as a // post-analysis to determine what was never visited. // -// A similar flow-sensitive only check exists in Analysis/UnreachableCode.cpp +// A similar flow-sensitive only check exists in Analysis/ReachableCode.cpp //===----------------------------------------------------------------------===// #include "clang/Checker/PathSensitive/CheckerVisitor.h" @@ -19,6 +19,7 @@ #include "clang/Checker/BugReporter/BugReporter.h" #include "GRExprEngineExperimentalChecks.h" #include "clang/AST/StmtCXX.h" +#include "clang/Basic/Builtins.h" #include "llvm/ADT/SmallPtrSet.h" // The number of CFGBlock pointers we want to reserve memory for. This is used @@ -79,6 +80,8 @@ void UnreachableCodeChecker::VisitEndAnalysis(ExplodedGraph &G, if (!C) return; + ASTContext &Ctx = B.getContext(); + // Find CFGBlocks that were not covered by any node for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) { const CFGBlock *CB = *I; @@ -96,6 +99,18 @@ void UnreachableCodeChecker::VisitEndAnalysis(ExplodedGraph &G, if (S.getBegin().isMacroID() || S.getEnd().isMacroID() || S.isInvalid() || SL.isInvalid()) continue; + + // Special case for __builtin_unreachable. + // FIXME: This should be extended to include other unreachable markers, + // such as llvm_unreachable. + if (!CB->empty()) { + const Stmt *First = CB->front(); + if (const CallExpr *CE = dyn_cast(First)) { + if (CE->isBuiltinCall(Ctx) == Builtin::BI__builtin_unreachable) + continue; + } + } + B.EmitBasicReport("Unreachable code", "This statement is never executed", SL, S); } diff --git a/test/Analysis/unreachable-code-path.c b/test/Analysis/unreachable-code-path.c index cfe0408c3f..e7e1d0b3eb 100644 --- a/test/Analysis/unreachable-code-path.c +++ b/test/Analysis/unreachable-code-path.c @@ -53,3 +53,9 @@ void test5(const char *c) { } } +void test6(const char *c) { + if (c) return; + if (!c) return; + __builtin_unreachable(); // no-warning +} + -- 2.40.0