-Wunreachable-code: 'true' and 'false' should not be treated as configuration
macros
Clang should emit -Wunreachable-code warnings in C mode for code that's
unreachable because of a 'false' or '!true' condition.
rdar://31452734
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@299541 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 2c1528e18a33f31e3b639fa92adcb63117222b08)
diff --git a/lib/Analysis/ReachableCode.cpp b/lib/Analysis/ReachableCode.cpp
index a2f3203..8a96744 100644
--- a/lib/Analysis/ReachableCode.cpp
+++ b/lib/Analysis/ReachableCode.cpp
@@ -132,15 +132,21 @@
// so that we can refine it later.
SourceLocation L = S->getLocStart();
if (L.isMacroID()) {
+ SourceManager &SM = PP.getSourceManager();
if (IgnoreYES_NO) {
// The Objective-C constant 'YES' and 'NO'
// are defined as macros. Do not treat them
// as configuration values.
- SourceManager &SM = PP.getSourceManager();
SourceLocation TopL = getTopMostMacro(L, SM);
StringRef MacroName = PP.getImmediateMacroName(TopL);
if (MacroName == "YES" || MacroName == "NO")
return false;
+ } else if (!PP.getLangOpts().CPlusPlus) {
+ // Do not treat C 'false' and 'true' macros as configuration values.
+ SourceLocation TopL = getTopMostMacro(L, SM);
+ StringRef MacroName = PP.getImmediateMacroName(TopL);
+ if (MacroName == "false" || MacroName == "true")
+ return false;
}
return true;
}
diff --git a/test/Sema/warn-unreachable.c b/test/Sema/warn-unreachable.c
index 34e0296..1f79216 100644
--- a/test/Sema/warn-unreachable.c
+++ b/test/Sema/warn-unreachable.c
@@ -451,3 +451,13 @@
// CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:15}:")"
unaryOpFixitCastSubExpr(x); // expected-warning {{code will never be executed}}
}
+
+#define false 0
+#define true 1
+
+void testTrueFalseMacros() {
+ if (false) // expected-note {{silence by adding parentheses to mark code as explicitly dead}}
+ testTrueFalseMacros(); // expected-warning {{code will never be executed}}
+ if (!true) // expected-note {{silence by adding parentheses to mark code as explicitly dead}}
+ testTrueFalseMacros(); // expected-warning {{code will never be executed}}
+}
