[PATCH] D28946: [analyzer] Fix memory space for block-captured static locals.

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This revision was automatically updated to reflect the committed changes.
Closed by commit rL293043: [analyzer] Fix MacOSXAPIChecker fp with static 
locals seen from nested blocks. (authored by dergachev).

Changed prior to commit:
  https://reviews.llvm.org/D28946?vs=85588&id=85722#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D28946

Files:
  cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
  cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
  cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
  cfe/trunk/test/Analysis/dispatch-once.m
  cfe/trunk/test/Analysis/null-deref-static.m


Index: cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ cfe/trunk/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1849,6 +1849,8 @@
 
     // Function-scoped static variables are default-initialized to 0; if they
     // have an initializer, it would have been processed by now.
+    // FIXME: This is only true when we're starting analysis from main().
+    // We're losing a lot of coverage here.
     if (isa<StaticGlobalSpaceRegion>(MS))
       return svalBuilder.makeZeroVal(T);
 
Index: cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ cfe/trunk/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -816,9 +816,11 @@
 
     const StackFrameContext *STC = V.get<const StackFrameContext*>();
 
-    if (!STC)
+    if (!STC) {
+      // FIXME: Assign a more sensible memory space to static locals
+      // we see from within blocks that we analyze as top-level declarations.
       sReg = getUnknownRegion();
-    else {
+    } else {
       if (D->hasLocalStorage()) {
         sReg = isa<ParmVarDecl>(D) || isa<ImplicitParamDecl>(D)
                ? static_cast<const MemRegion*>(getStackArgumentsRegion(STC))
Index: cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/MacOSXAPIChecker.cpp
@@ -94,11 +94,18 @@
   bool SuggestStatic = false;
   os << "Call to '" << FName << "' uses";
   if (const VarRegion *VR = dyn_cast<VarRegion>(RB)) {
+    const VarDecl *VD = VR->getDecl();
+    // FIXME: These should have correct memory space and thus should be filtered
+    // out earlier. This branch only fires when we're looking from a block,
+    // which we analyze as a top-level declaration, onto a static local
+    // in a function that contains the block.
+    if (VD->isStaticLocal())
+      return;
     // We filtered out globals earlier, so it must be a local variable
     // or a block variable which is under UnknownSpaceRegion.
     if (VR != R)
       os << " memory within";
-    if (VR->getDecl()->hasAttr<BlocksAttr>())
+    if (VD->hasAttr<BlocksAttr>())
       os << " the block variable '";
     else
       os << " the local variable '";
Index: cfe/trunk/test/Analysis/null-deref-static.m
===================================================================
--- cfe/trunk/test/Analysis/null-deref-static.m
+++ cfe/trunk/test/Analysis/null-deref-static.m
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -w -fblocks -analyze -analyzer-checker=core,deadcode,alpha.core,debug.ExprInspection -verify %s
+
+void *malloc(unsigned long);
+void clang_analyzer_warnIfReached();
+
+void test_static_from_block() {
+  static int *x;
+  ^{
+    *x; // no-warning
+  };
+}
+
+void test_static_within_block() {
+  ^{
+    static int *x;
+    *x; // expected-warning{{Dereference of null pointer}}
+  };
+}
+
+void test_static_control_flow(int y) {
+  static int *x;
+  if (x) {
+    // FIXME: Should be reachable.
+    clang_analyzer_warnIfReached(); // no-warning
+  }
+  if (y) {
+    // We are not sure if this branch is possible, because the developer
+    // may argue that function is always called with y == 1 for the first time.
+    // In this case, we can only advise the developer to add assertions
+    // for suppressing such path.
+    *x; // expected-warning{{Dereference of null pointer}}
+  } else {
+    x = malloc(1);
+  }
+}
Index: cfe/trunk/test/Analysis/dispatch-once.m
===================================================================
--- cfe/trunk/test/Analysis/dispatch-once.m
+++ cfe/trunk/test/Analysis/dispatch-once.m
@@ -107,3 +107,10 @@
   };
   dispatch_once(&once, ^{}); // expected-warning{{Call to 'dispatch_once' uses the block variable 'once' for the predicate value.}}
 }
+
+void test_static_var_from_outside_block() {
+  static dispatch_once_t once;
+  ^{
+    dispatch_once(&once, ^{}); // no-warning
+  };
+}

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