Extend Evaluate() to fold (int) <pointer type>.

 - PR3463, PR3398, <rdar://problem/6553401> crash on relocatable
   symbol addresses as constants in static locals.

 - There are many more scenarious we could handle (like arithmetic on
   such an int) but this is the main use case.

llvm-svn: 65074

2 files changed, 39 insertions, 4 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index cfe1a74f320..5e08e52a7ca 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1057,7 +1057,7 @@ bool IntExprEvaluator::VisitCastExpr(CastExpr *E) {
     if (!Result.isInt())
       return false;
 
-    return Success(HandleIntToIntCast(DestType, SrcType, 
+    return Success(HandleIntToIntCast(DestType, SrcType,
                                       Result.getInt(), Info.Ctx), E);
   }
   
@@ -1067,10 +1067,17 @@ bool IntExprEvaluator::VisitCastExpr(CastExpr *E) {
     if (!EvaluatePointer(SubExpr, LV, Info))
       return false;
 
-    if (LV.getLValueBase())
-      return false;
+    if (LV.getLValueBase()) {
+      // Only allow based lvalue casts if they are lossless.
+      if (Info.Ctx.getTypeSize(DestType) != Info.Ctx.getTypeSize(SrcType))
+        return false;
+
+      Result = LV;
+      return true;
+    }
 
-    return Success(LV.getLValueOffset(), E);
+    APSInt AsInt = Info.Ctx.MakeIntValue(LV.getLValueOffset(), SrcType);
+    return Success(HandleIntToIntCast(DestType, SrcType, AsInt, Info.Ctx), E);
   }
 
   if (!SrcType->isRealFloatingType())
diff --git a/clang/test/CodeGen/const-init.c b/clang/test/CodeGen/const-init.c
index c98cfd4ca22..957e3733e41 100644
--- a/clang/test/CodeGen/const-init.c
+++ b/clang/test/CodeGen/const-init.c
@@ -48,4 +48,32 @@ int g9 = (2 + 3i) * (5 + 7i) != (-11 + 29i);
 int g10 = (2.0 + 3.0i) * (5.0 + 7.0i) != (-11.0 + 29.0i);
 
 
+// Global references
+// RUN: grep '@g11.l0 = internal global i32 ptrtoint (i32 ()\* @g11 to i32)' %t &&
+long g11() { 
+  static long l0 = (long) g11;
+  return l0; 
+}
+
+// RUN: grep '@g12 = global i32 ptrtoint (i8\* @g12_tmp to i32)' %t &&
+static char g12_tmp;
+long g12 = (long) &g12_tmp;
+
+// RUN: grep '@g13 = global \[1 x .struct.g13_s0\] \[.struct.g13_s0 <{ i32 ptrtoint (i8\* @g12_tmp to i32) }>\]' %t &&
+struct g13_s0 {
+   long a;
+};
+struct g13_s0 g13[] = {
+   { (long) &g12_tmp }
+};
+
+// RUN: grep '@g14 = global i8\* inttoptr (i64 100 to i8\*)' %t &&
+void *g14 = (void*) 100;
+
+// RUN: grep '@g15 = global i32 -1' %t &&
+int g15 = (int) (char) ((void*) 0 + 255);
+
+// RUN: grep '@g16 = global i64 4294967295' %t &&
+long long g16 = (long long) ((void*) 0xFFFFFFFF);
+
 // RUN: true