[PATCH] D39174: [analyzer] Fix handling of labels getLValueElement

[Alexander Shaposhnikov via Phabricator via cfe-commits]

alexshap created this revision.
Herald added subscribers: szepet, xazax.hun.

In getLValueElement Base may represent the address of a label (as in the 
newly-added test case),
in this case it's not a loc::MemRegionVal and Base.castAs<loc::MemRegionVal>() 
triggers an assert.

Test plan: make check-all


Repository:
  rL LLVM

https://reviews.llvm.org/D39174

Files:
  lib/StaticAnalyzer/Core/Store.cpp
  test/Analysis/ptr-arith.c


Index: test/Analysis/ptr-arith.c
===================================================================
--- test/Analysis/ptr-arith.c
+++ test/Analysis/ptr-arith.c
@@ -342,3 +342,8 @@
   clang_analyzer_eval(*ptr3 == 'a'); // expected-warning{{UNKNOWN}}
 }
 
+void test_no_crash_on_pointer_to_label() {
+  char *a = &&label;
+  a[0] = 0;
+label:;
+}
Index: lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Store.cpp
+++ lib/StaticAnalyzer/Core/Store.cpp
@@ -440,7 +440,10 @@
   //  value. See also the similar FIXME in getLValueFieldOrIvar().
   if (Base.isUnknownOrUndef() || Base.getAs<loc::ConcreteInt>())
     return Base;
-
+  
+  if (Base.getAs<loc::GotoLabel>())
+    return UnknownVal();
+  
   const SubRegion *BaseRegion =
       Base.castAs<loc::MemRegionVal>().getRegionAs<SubRegion>();
 



Index: test/Analysis/ptr-arith.c
===================================================================
--- test/Analysis/ptr-arith.c
+++ test/Analysis/ptr-arith.c
@@ -342,3 +342,8 @@
   clang_analyzer_eval(*ptr3 == 'a'); // expected-warning{{UNKNOWN}}
 }
 
+void test_no_crash_on_pointer_to_label() {
+  char *a = &&label;
+  a[0] = 0;
+label:;
+}
Index: lib/StaticAnalyzer/Core/Store.cpp
===================================================================
--- lib/StaticAnalyzer/Core/Store.cpp
+++ lib/StaticAnalyzer/Core/Store.cpp
@@ -440,7 +440,10 @@
   //  value. See also the similar FIXME in getLValueFieldOrIvar().
   if (Base.isUnknownOrUndef() || Base.getAs<loc::ConcreteInt>())
     return Base;
-
+  
+  if (Base.getAs<loc::GotoLabel>())
+    return UnknownVal();
+  
   const SubRegion *BaseRegion =
       Base.castAs<loc::MemRegionVal>().getRegionAs<SubRegion>();
 

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