[cfe-commits] r143496 - in /cfe/trunk: lib/AST/ExprConstant.cpp test/Sema/const-eval.c
Richard Smith
richard-llvm at metafoo.co.uk
Tue Nov 1 14:06:14 PDT 2011
Author: rsmith
Date: Tue Nov 1 16:06:14 2011
New Revision: 143496
URL: http://llvm.org/viewvc/llvm-project?rev=143496&view=rev
Log:
When constant-folding, don't look at the initializer of a global const variable
if it's marked as weak: that definition may not end up being used.
Modified:
cfe/trunk/lib/AST/ExprConstant.cpp
cfe/trunk/test/Sema/const-eval.c
Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=143496&r1=143495&r2=143496&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Nov 1 16:06:14 2011
@@ -270,16 +270,17 @@
!isa<MaterializeTemporaryExpr>(Value.Base);
}
-static bool IsWeakLValue(const LValue &Value) {
- const ValueDecl *Decl = GetLValueBaseDecl(Value);
- if (!Decl)
- return false;
-
+static bool IsWeakDecl(const ValueDecl *Decl) {
return Decl->hasAttr<WeakAttr>() ||
Decl->hasAttr<WeakRefAttr>() ||
Decl->isWeakImported();
}
+static bool IsWeakLValue(const LValue &Value) {
+ const ValueDecl *Decl = GetLValueBaseDecl(Value);
+ return Decl && IsWeakDecl(Decl);
+}
+
static bool EvalPointerValueAsBool(const LValue &Value, bool &Result) {
const Expr* Base = Value.Base;
@@ -394,6 +395,11 @@
return true;
}
+ // Never evaluate the initializer of a weak variable. We can't be sure that
+ // this is the definition which will be used.
+ if (IsWeakDecl(VD))
+ return false;
+
const Expr *Init = VD->getAnyInitializer();
if (!Init)
return false;
Modified: cfe/trunk/test/Sema/const-eval.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/const-eval.c?rev=143496&r1=143495&r2=143496&view=diff
==============================================================================
--- cfe/trunk/test/Sema/const-eval.c (original)
+++ cfe/trunk/test/Sema/const-eval.c Tue Nov 1 16:06:14 2011
@@ -95,3 +95,7 @@
union u { int a; char b[4]; };
char c = ((union u)(123456)).b[0]; // expected-error {{not a compile-time constant}}
+
+extern const int weak_int __attribute__((weak));
+const int weak_int = 42;
+int weak_int_test = weak_int; // expected-error {{not a compile-time constant}}
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