[PATCH] D25606: alpha.core.UnreachableCode - don't warn about unreachable code inside macro

[Daniel Marjamäki via cfe-commits]

danielmarjamaki created this revision.
danielmarjamaki added reviewers: NoQ, dcoughlin.
danielmarjamaki added subscribers: cfe-commits, xazax.hun, zaks.anna, a.sidorin.
danielmarjamaki set the repository for this revision to rL LLVM.

This patch fixes false positives for such code:

  #define RETURN(X)  do { return; } while (0)
  
  void dostuff(void) {
    RETURN(1); // no-warning
  }

The condition "0" in the macro is unreachable but that condition is there for a good reason.


Repository:
  rL LLVM

https://reviews.llvm.org/D25606

Files:
  lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
  test/Analysis/unreachable-code-path.c


Index: test/Analysis/unreachable-code-path.c
===================================================================
--- test/Analysis/unreachable-code-path.c
+++ test/Analysis/unreachable-code-path.c
@@ -206,3 +206,10 @@
   int x = inlineFunction(i);
   x && x < 10; // no-warning
 }
+
+// Don't warn in a macro
+#define RETURN(X)  do { return; } while (0)
+void macro(void) {
+  RETURN(1); // no-warning
+}
+
Index: lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -147,6 +147,8 @@
     PathDiagnosticLocation DL;
     SourceLocation SL;
     if (const Stmt *S = getUnreachableStmt(CB)) {
+      if (S->getLocStart().isMacroID())
+        continue;
       SR = S->getSourceRange();
       DL = PathDiagnosticLocation::createBegin(S, B.getSourceManager(), LC);
       SL = DL.asLocation();


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