r180864 - Re-apply "[analyzer] Model casts to bool differently from other numbers."

Jordan Rose jordan_rose at apple.com
Wed May 1 11:20:00 PDT 2013


Author: jrose
Date: Wed May  1 13:19:59 2013
New Revision: 180864

URL: http://llvm.org/viewvc/llvm-project?rev=180864&view=rev
Log:
Re-apply "[analyzer] Model casts to bool differently from other numbers."

This doesn't appear to be the cause of the slowdown. I'll have to try a
manual bisect to see if there's really anything there, or if it's just
the bot itself taking on additional load. Meanwhile, this change helps
with correctness.

This changes an assertion and adds a test case, then re-applies r180638,
which was reverted in r180714.

<rdar://problem/13296133> and PR15863

Modified:
    cfe/trunk/lib/StaticAnalyzer/Core/SValBuilder.cpp
    cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
    cfe/trunk/test/Analysis/bool-assignment.c
    cfe/trunk/test/Analysis/casts.c
    cfe/trunk/test/Analysis/stack-addr-ps.cpp
    cfe/trunk/test/Analysis/stackaddrleak.c
    cfe/trunk/test/Analysis/svalbuilder-logic.c

Modified: cfe/trunk/lib/StaticAnalyzer/Core/SValBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/SValBuilder.cpp?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/SValBuilder.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/SValBuilder.cpp Wed May  1 13:19:59 2013
@@ -327,6 +327,22 @@ SVal SValBuilder::evalCast(SVal val, Qua
   if (val.isUnknownOrUndef() || castTy == originalTy)
     return val;
 
+  if (castTy->isBooleanType()) {
+    if (val.isUnknownOrUndef())
+      return val;
+    if (val.isConstant())
+      return makeTruthVal(!val.isZeroConstant(), castTy);
+    if (SymbolRef Sym = val.getAsSymbol()) {
+      BasicValueFactory &BVF = getBasicValueFactory();
+      // FIXME: If we had a state here, we could see if the symbol is known to
+      // be zero, but we don't.
+      return makeNonLoc(Sym, BO_NE, BVF.getValue(0, Sym->getType()), castTy);
+    }
+
+    assert(val.getAs<Loc>());
+    return makeTruthVal(true, castTy);
+  }
+
   // For const casts, casts to void, just propagate the value.
   if (!castTy->isVariableArrayType() && !originalTy->isVariableArrayType())
     if (shouldBeModeledWithNoOp(Context, Context.getPointerType(castTy),

Modified: cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp Wed May  1 13:19:59 2013
@@ -438,9 +438,13 @@ SVal SimpleSValBuilder::evalBinOpNN(Prog
           case BO_GE:
           case BO_EQ:
           case BO_NE:
+            assert(resultTy->isBooleanType() ||
+                   resultTy == getConditionType());
+            assert(symIntExpr->getType()->isBooleanType() ||
+                   getContext().hasSameUnqualifiedType(symIntExpr->getType(),
+                                                       getConditionType()));
             // Negate the comparison and make a value.
             opc = BinaryOperator::negateComparisonOp(opc);
-            assert(symIntExpr->getType() == resultTy);
             return makeNonLoc(symIntExpr->getLHS(), opc,
                 symIntExpr->getRHS(), resultTy);
           }

Modified: cfe/trunk/test/Analysis/bool-assignment.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/bool-assignment.c?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/bool-assignment.c (original)
+++ cfe/trunk/test/Analysis/bool-assignment.c Wed May  1 13:19:59 2013
@@ -1,15 +1,19 @@
 // RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core.BoolAssignment -analyzer-store=region -verify -std=c99 -Dbool=_Bool %s
 // RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core.BoolAssignment -analyzer-store=region -verify -x c++ %s
 
-// Test C++'s bool and C's _Bool
+// Test C++'s bool and C's _Bool.
+// FIXME: We stopped warning on these when SValBuilder got smarter about
+// casts to bool. Arguably, however, these conversions are okay; the result
+// is always 'true' or 'false'.
 
 void test_stdbool_initialization(int y) {
+  bool constant = 2; // no-warning
   if (y < 0) {
-    bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+    bool x = y; // no-warning
     return;
   }
   if (y > 1) {
-    bool x = y; // expected-warning {{Assignment of a non-Boolean value}}
+    bool x = y; // no-warning
     return;
   }
   bool x = y; // no-warning
@@ -18,11 +22,11 @@ void test_stdbool_initialization(int y)
 void test_stdbool_assignment(int y) {
   bool x = 0; // no-warning
   if (y < 0) {
-    x = y; // expected-warning {{Assignment of a non-Boolean value}}
+    x = y; // no-warning
     return;
   }
   if (y > 1) {
-    x = y; // expected-warning {{Assignment of a non-Boolean value}}
+    x = y; // no-warning
     return;
   }
   x = y; // no-warning
@@ -33,6 +37,7 @@ void test_stdbool_assignment(int y) {
 typedef signed char BOOL;
 
 void test_BOOL_initialization(int y) {
+  BOOL constant = 2; // expected-warning {{Assignment of a non-Boolean value}}
   if (y < 0) {
     BOOL x = y; // expected-warning {{Assignment of a non-Boolean value}}
     return;
@@ -63,6 +68,7 @@ void test_BOOL_assignment(int y) {
 typedef unsigned char Boolean;
 
 void test_Boolean_initialization(int y) {
+  Boolean constant = 2; // expected-warning {{Assignment of a non-Boolean value}}
   if (y < 0) {
     Boolean x = y; // expected-warning {{Assignment of a non-Boolean value}}
     return;

Modified: cfe/trunk/test/Analysis/casts.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/casts.c?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/casts.c (original)
+++ cfe/trunk/test/Analysis/casts.c Wed May  1 13:19:59 2013
@@ -1,6 +1,7 @@
-// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze -analyzer-checker=core,alpha.core -analyzer-store=region -verify %s
-// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze -analyzer-checker=core,alpha.core -analyzer-store=region -verify %s
-// expected-no-diagnostics
+// RUN: %clang_cc1 -triple x86_64-apple-darwin9 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -analyzer-store=region -verify %s
+// RUN: %clang_cc1 -triple i386-apple-darwin9 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -analyzer-store=region -verify %s
+
+extern void clang_analyzer_eval(_Bool);
 
 // Test if the 'storage' region gets properly initialized after it is cast to
 // 'struct sockaddr *'. 
@@ -85,3 +86,34 @@ int foo (int* p) {
   }
   return 0;
 }
+
+void castsToBool() {
+  clang_analyzer_eval(0); // expected-warning{{FALSE}}
+  clang_analyzer_eval(0U); // expected-warning{{FALSE}}
+  clang_analyzer_eval((void *)0); // expected-warning{{FALSE}}
+
+  clang_analyzer_eval(1); // expected-warning{{TRUE}}
+  clang_analyzer_eval(1U); // expected-warning{{TRUE}}
+  clang_analyzer_eval(-1); // expected-warning{{TRUE}}
+  clang_analyzer_eval(0x100); // expected-warning{{TRUE}}
+  clang_analyzer_eval(0x100U); // expected-warning{{TRUE}}
+  clang_analyzer_eval((void *)0x100); // expected-warning{{TRUE}}
+
+  extern int symbolicInt;
+  clang_analyzer_eval(symbolicInt); // expected-warning{{UNKNOWN}}
+  if (symbolicInt)
+    clang_analyzer_eval(symbolicInt); // expected-warning{{TRUE}}
+
+  extern void *symbolicPointer;
+  clang_analyzer_eval(symbolicPointer); // expected-warning{{UNKNOWN}}
+  if (symbolicPointer)
+    clang_analyzer_eval(symbolicPointer); // expected-warning{{TRUE}}
+
+  int localInt;
+  clang_analyzer_eval(&localInt); // expected-warning{{TRUE}}
+  clang_analyzer_eval(&castsToBool); // expected-warning{{TRUE}}
+  clang_analyzer_eval("abc"); // expected-warning{{TRUE}}
+
+  extern float globalFloat;
+  clang_analyzer_eval(globalFloat); // expected-warning{{UNKNOWN}}
+}

Modified: cfe/trunk/test/Analysis/stack-addr-ps.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/stack-addr-ps.cpp?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/stack-addr-ps.cpp (original)
+++ cfe/trunk/test/Analysis/stack-addr-ps.cpp Wed May  1 13:19:59 2013
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -analyze -analyzer-checker=core -analyzer-store=region -verify %s
 
-// FIXME: Only the stack-address checking in Sema catches this right now, and
-// the stack analyzer doesn't handle the ImplicitCastExpr (lvalue).
+typedef __INTPTR_TYPE__ intptr_t;
+
 const int& g() {
   int s;
   return s; // expected-warning{{Address of stack memory associated with local variable 's' returned}} expected-warning{{reference to stack memory associated with local variable 's' returned}}
@@ -96,3 +96,40 @@ void *radar13226577() {
     return p; // expected-warning {{stack memory associated with local variable 'p' returned to caller}}
 }
 
+namespace rdar13296133 {
+  class ConvertsToBool {
+  public:
+    operator bool() const { return this; }
+  };
+
+  class ConvertsToIntptr {
+  public:
+    operator intptr_t() const { return reinterpret_cast<intptr_t>(this); }
+  };
+
+  class ConvertsToPointer {
+  public:
+    operator const void *() const { return this; }
+  };
+
+  intptr_t returnAsNonLoc() {
+    ConvertsToIntptr obj;
+    return obj; // expected-warning{{Address of stack memory associated with local variable 'obj' returned to caller}}
+  }
+
+  bool returnAsBool() {
+    ConvertsToBool obj;
+    return obj; // no-warning
+  }
+
+  intptr_t returnAsNonLocViaPointer() {
+    ConvertsToPointer obj;
+    return reinterpret_cast<intptr_t>(static_cast<const void *>(obj)); // expected-warning{{Address of stack memory associated with local variable 'obj' returned to caller}}
+  }
+
+  bool returnAsBoolViaPointer() {
+    ConvertsToPointer obj;
+    return obj; // no-warning
+  }
+}
+

Modified: cfe/trunk/test/Analysis/stackaddrleak.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/stackaddrleak.c?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/stackaddrleak.c (original)
+++ cfe/trunk/test/Analysis/stackaddrleak.c Wed May  1 13:19:59 2013
@@ -1,5 +1,7 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core -analyzer-store region -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core -verify -std=c99 -Dbool=_Bool %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core -verify -x c++ %s
 
+typedef __INTPTR_TYPE__ intptr_t;
 char const *p;
 
 void f0() {
@@ -15,7 +17,7 @@ void f1() {
 
 void f2() {
   p = (const char *) __builtin_alloca(12);
-} // expected-warning{{Address of stack memory allocated by call to alloca() on line 17 is still referred to by the global variable 'p' upon returning to the caller.  This will be a dangling reference}}
+} // expected-warning{{Address of stack memory allocated by call to alloca() on line 19 is still referred to by the global variable 'p' upon returning to the caller.  This will be a dangling reference}}
 
 // PR 7383 - previosly the stack address checker would crash on this example
 //  because it would attempt to do a direct load from 'pr7383_list'. 
@@ -32,3 +34,25 @@ void test_multi_return() {
   a = &x;
   b = &x;
 } // expected-warning{{Address of stack memory associated with local variable 'x' is still referred to by the global variable 'a' upon returning}} expected-warning{{Address of stack memory associated with local variable 'x' is still referred to by the global variable 'b' upon returning}}
+
+intptr_t returnAsNonLoc() {
+  int x;
+  return (intptr_t)&x; // expected-warning{{Address of stack memory associated with local variable 'x' returned to caller}}
+}
+
+bool returnAsBool() {
+  int x;
+  return &x; // no-warning
+}
+
+void assignAsNonLoc() {
+  extern intptr_t ip;
+  int x;
+  ip = (intptr_t)&x;
+} // expected-warning{{Address of stack memory associated with local variable 'x' is still referred to by the global variable 'ip' upon returning}}
+
+void assignAsBool() {
+  extern bool b;
+  int x;
+  b = &x;
+} // no-warning

Modified: cfe/trunk/test/Analysis/svalbuilder-logic.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/svalbuilder-logic.c?rev=180864&r1=180863&r2=180864&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/svalbuilder-logic.c (original)
+++ cfe/trunk/test/Analysis/svalbuilder-logic.c Wed May  1 13:19:59 2013
@@ -6,3 +6,11 @@
 int SValBuilderLogicNoCrash(int *x) {
   return 3 - (int)(x +3);
 }
+
+// http://llvm.org/bugs/show_bug.cgi?id=15863
+// Don't crash when mixing 'bool' and 'int' in implicit comparisons to 0.
+void pr15863() {
+  extern int getBool();
+  _Bool a = getBool();
+  (void)!a; // no-warning
+}





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