From 28cd22d7c2d2458575ce9cc19dfe63c6321010ce Mon Sep 17 00:00:00 2001 From: Ted Kremenek Date: Wed, 29 Feb 2012 06:05:28 +0000 Subject: [PATCH] [analyzer] Tweak the UnreachableCode checker to not warning about unreachable default blocks. Patch by Cyril Roelandt! git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@151709 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../Checkers/UnreachableCodeChecker.cpp | 8 ++++++++ test/Analysis/unreachable-code-path.c | 17 +++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp index 2b550df2b9..8ac785ce7d 100644 --- a/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp +++ b/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp @@ -116,6 +116,14 @@ void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G, if (CB->size() > 0 && isInvalidPath(CB, *PM)) continue; + // It is good practice to always have a "default" label in a "switch", even + // if we should never get there. It can be used to detect errors, for + // instance. Unreachable code directly under a "default" label is therefore + // likely to be a false positive. + if (const Stmt *label = CB->getLabel()) + if (label->getStmtClass() == Stmt::DefaultStmtClass) + continue; + // Special case for __builtin_unreachable. // FIXME: This should be extended to include other unreachable markers, // such as llvm_unreachable. diff --git a/test/Analysis/unreachable-code-path.c b/test/Analysis/unreachable-code-path.c index da14f4c010..48a3462ca1 100644 --- a/test/Analysis/unreachable-code-path.c +++ b/test/Analysis/unreachable-code-path.c @@ -122,3 +122,20 @@ void test10() { goto d; f: ; } + +// test11: we can actually end up in the default case, even if it is not +// obvious: there might be something wrong with the given argument. +enum foobar { FOO, BAR }; +extern void error(); +void test11(enum foobar fb) { + switch (fb) { + case FOO: + break; + case BAR: + break; + default: + error(); // no-warning + return; + error(); // expected-warning {{never executed}} + } +} -- 2.50.1