[cfe-commits] r146753 - in /cfe/trunk: include/clang/Sema/Sema.h lib/Sema/SemaChecking.cpp lib/Sema/SemaExpr.cpp test/Sema/array-bounds-ptr-arith.c

[Richard Smith]

Author: rsmith
Date: Fri Dec 16 13:31:14 2011
New Revision: 146753

URL: http://llvm.org/viewvc/llvm-project?rev=146753&view=rev
Log:
PR11594: Don't blindly build a UnaryOperator UO_Minus on an expression which
might not be an rvalue when checking array accesses. Instead, pass through a
flag indicating the array index is negated.

Modified:
    cfe/trunk/include/clang/Sema/Sema.h
    cfe/trunk/lib/Sema/SemaChecking.cpp
    cfe/trunk/lib/Sema/SemaExpr.cpp
    cfe/trunk/test/Sema/array-bounds-ptr-arith.c

Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=146753&r1=146752&r2=146753&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Fri Dec 16 13:31:14 2011
@@ -6200,7 +6200,7 @@
 private:
   void CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                         const ArraySubscriptExpr *ASE=0,
-                        bool AllowOnePastEnd=true);
+                        bool AllowOnePastEnd=true, bool IndexNegated=false);
   void CheckArrayAccess(const Expr *E);
   bool CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall);
   bool CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall);

Modified: cfe/trunk/lib/Sema/SemaChecking.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaChecking.cpp?rev=146753&r1=146752&r2=146753&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaChecking.cpp (original)
+++ cfe/trunk/lib/Sema/SemaChecking.cpp Fri Dec 16 13:31:14 2011
@@ -4277,7 +4277,7 @@
 
 void Sema::CheckArrayAccess(const Expr *BaseExpr, const Expr *IndexExpr,
                             const ArraySubscriptExpr *ASE,
-                            bool AllowOnePastEnd) {
+                            bool AllowOnePastEnd, bool IndexNegated) {
   IndexExpr = IndexExpr->IgnoreParenCasts();
   if (IndexExpr->isValueDependent())
     return;
@@ -4292,6 +4292,8 @@
   llvm::APSInt index;
   if (!IndexExpr->EvaluateAsInt(index, Context))
     return;
+  if (IndexNegated)
+    index = -index;
 
   const NamedDecl *ND = NULL;
   if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(BaseExpr))

Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=146753&r1=146752&r2=146753&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Fri Dec 16 13:31:14 2011
@@ -6203,11 +6203,9 @@
       if (!checkArithmeticOpPointerOperand(*this, Loc, LHS.get()))
         return QualType();
 
-      Expr *IExpr = RHS.get()->IgnoreParenCasts();
-      UnaryOperator negRex(IExpr, UO_Minus, IExpr->getType(), VK_RValue,
-                           OK_Ordinary, IExpr->getExprLoc());
       // Check array bounds for pointer arithemtic
-      CheckArrayAccess(LHS.get()->IgnoreParenCasts(), &negRex);
+      CheckArrayAccess(LHS.get(), RHS.get(), /*ArraySubscriptExpr*/0,
+                       /*AllowOnePastEnd*/true, /*IndexNegated*/true);
 
       if (CompLHSTy) *CompLHSTy = LHS.get()->getType();
       return LHS.get()->getType();

Modified: cfe/trunk/test/Sema/array-bounds-ptr-arith.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/array-bounds-ptr-arith.c?rev=146753&r1=146752&r2=146753&view=diff
==============================================================================
--- cfe/trunk/test/Sema/array-bounds-ptr-arith.c (original)
+++ cfe/trunk/test/Sema/array-bounds-ptr-arith.c Fri Dec 16 13:31:14 2011
@@ -12,3 +12,10 @@
 {
 	 return (void *)es->s_uuid + 80; // expected-warning {{refers past the end of the array}}
 }
+
+// Test case reduced from PR11594
+struct S { int n; };
+void pr11594(struct S *s) {
+  int a[10];
+  int *p = a - s->n;
+}