[PATCH] D38358: [analyzer] Fix autodetection of getSVal()'s type argument.

[Artem Dergachev via Phabricator via cfe-commits]

NoQ updated this revision to Diff 117360.
NoQ added a comment.

Yeah, nice catch. So we need to either always tell the checkers to specify their `CharTy` when they are dealing with void pointers, or to do our substitution consistently, not only for `SymbolicRegion` but also for `AllocaRegion` (did that in this diff).


https://reviews.llvm.org/D38358

Files:
  lib/StaticAnalyzer/Core/RegionStore.cpp
  test/Analysis/ctor.mm
  test/Analysis/exercise-ps.c
  test/Analysis/gtest.cpp


Index: test/Analysis/gtest.cpp
===================================================================
--- test/Analysis/gtest.cpp
+++ test/Analysis/gtest.cpp
@@ -151,3 +151,17 @@
   ASSERT_TRUE(false);
   clang_analyzer_warnIfReached(); // no-warning
 }
+
+void testAssertSymbolicPtr(const bool *b) {
+  ASSERT_TRUE(*b); // no-crash
+
+  // FIXME: Our solver doesn't handle this well yet.
+  clang_analyzer_eval(*b); // expected-warning{{UNKNOWN}}
+}
+
+void testAssertSymbolicRef(const bool &b) {
+  ASSERT_TRUE(b); // no-crash
+
+  // FIXME: Our solver doesn't handle this well yet.
+  clang_analyzer_eval(b); // expected-warning{{UNKNOWN}}
+}
Index: test/Analysis/exercise-ps.c
===================================================================
--- test/Analysis/exercise-ps.c
+++ test/Analysis/exercise-ps.c
@@ -21,3 +21,11 @@
   memcpy((&x[1]), (buf), 1); // expected-warning{{implicitly declaring library function 'memcpy' with type 'void *(void *, const void *}} \
   // expected-note{{include the header <string.h> or explicitly provide a declaration for 'memcpy'}}
 }
+
+// AllocaRegion is untyped. Void pointer isn't of much help either. Before
+// realizing that the value is undefined, we need to somehow figure out
+// what type of value do we expect.
+void f3(void *dest) {
+  void *src = __builtin_alloca(5);
+  memcpy(dest, src, 1); // expected-warning{{2nd function call argument is a pointer to uninitialized value}}
+}
Index: test/Analysis/ctor.mm
===================================================================
--- test/Analysis/ctor.mm
+++ test/Analysis/ctor.mm
@@ -199,7 +199,7 @@
     Inner p;
   };
 
-  void testPOD() {
+  void testPOD(const POD &pp) {
     POD p;
     p.x = 1;
     POD p2 = p; // no-warning
@@ -210,6 +210,15 @@
     // Use rvalues as well.
     clang_analyzer_eval(POD(p3).x == 1); // expected-warning{{TRUE}}
 
+    // Copy from symbolic references correctly.
+    POD p4 = pp;
+    // Make sure that p4.x contains a symbol after copy.
+    if (p4.x > 0)
+      clang_analyzer_eval(p4.x > 0); // expected-warning{{TRUE}}
+    // FIXME: Element region gets in the way, so these aren't the same symbols
+    // as they should be.
+    clang_analyzer_eval(pp.x == p4.x); // expected-warning{{UNKNOWN}}
+
     PODWrapper w;
     w.p.y = 1;
     PODWrapper w2 = w; // no-warning
Index: lib/StaticAnalyzer/Core/RegionStore.cpp
===================================================================
--- lib/StaticAnalyzer/Core/RegionStore.cpp
+++ lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1393,16 +1393,19 @@
     return UnknownVal();
   }
 
-  if (isa<AllocaRegion>(MR) ||
-      isa<SymbolicRegion>(MR) ||
-      isa<CodeTextRegion>(MR)) {
+  if (!isa<TypedValueRegion>(MR)) {
     if (T.isNull()) {
       if (const TypedRegion *TR = dyn_cast<TypedRegion>(MR))
-        T = TR->getLocationType();
-      else {
-        const SymbolicRegion *SR = cast<SymbolicRegion>(MR);
-        T = SR->getSymbol()->getType();
-      }
+        T = TR->getLocationType()->getPointeeType();
+      else if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(MR))
+        T = SR->getSymbol()->getType()->getPointeeType();
+      else if (isa<AllocaRegion>(MR))
+        T = Ctx.VoidTy;
+    }
+    assert(!T.isNull() && "Unable to auto-detect binding type!");
+    if (T->isVoidType()) {
+      // When trying to dereference a void pointer, read the first byte.
+      T = Ctx.CharTy;
     }
     MR = GetElementZeroRegion(cast<SubRegion>(MR), T);
   }


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