[cfe-commits] r54009 - in /cfe/trunk: lib/Analysis/CheckDeadStores.cpp test/Analysis/dead-stores.c

[Ted Kremenek]

Author: kremenek
Date: Thu Jul 24 23:47:34 2008
New Revision: 54009

URL: http://llvm.org/viewvc/llvm-project?rev=54009&view=rev
Log:
Don't emit 'dead initialization' warnings for variables marked 'unused'.
This fixes PR 2573: http://llvm.org/bugs/show_bug.cgi?id=2573

Modified:
    cfe/trunk/lib/Analysis/CheckDeadStores.cpp
    cfe/trunk/test/Analysis/dead-stores.c

Modified: cfe/trunk/lib/Analysis/CheckDeadStores.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CheckDeadStores.cpp?rev=54009&r1=54008&r2=54009&view=diff

==============================================================================
--- cfe/trunk/lib/Analysis/CheckDeadStores.cpp (original)
+++ cfe/trunk/lib/Analysis/CheckDeadStores.cpp Thu Jul 24 23:47:34 2008
@@ -164,11 +164,16 @@
       for (ScopedDecl* SD = DS->getDecl(); SD; SD = SD->getNextDeclarator()) {
         
         VarDecl* V = dyn_cast<VarDecl>(SD);
-        if (!V) continue;
+
+        if (!V)
+          continue;
         
         if (V->hasLocalStorage())
-          if (Expr* E = V->getInit())
-            if (!Live(V, AD)) {
+          if (Expr* E = V->getInit()) {
+            // A dead initialization is a variable that is dead after it
+            // is initialized.  We don't flag warnings for those variables
+            // marked 'unused'.
+            if (!Live(V, AD) && V->getAttr<UnusedAttr>() == 0) {
               // Special case: check for initializations with constants.
               //
               //  e.g. : int x = 0;
@@ -179,6 +184,7 @@
               if (!E->isConstantExpr(Ctx,NULL))
                 Report(V, DeadInit, V->getLocation(), E->getSourceRange());
             }
+          }
       }
   }
 };

Modified: cfe/trunk/test/Analysis/dead-stores.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/dead-stores.c?rev=54009&r1=54008&r2=54009&view=diff

==============================================================================
--- cfe/trunk/test/Analysis/dead-stores.c (original)
+++ cfe/trunk/test/Analysis/dead-stores.c Thu Jul 24 23:47:34 2008
@@ -77,5 +77,12 @@
   return ++x; // expected-warning{{never read}}
 }
 
-
+int f12a(int y) {
+  int x = y;  // expected-warning{{never read}}
+  return 1;
+}
+int f12b(int y) {
+  int x __attribute__((unused)) = y;  // no-warning
+  return 1;
+}