Widen EHScope::ClenupBitFields::FixupDepth to avoid overflowing it (PR23490)
It currently only takes 2048 gotos to overflow the FixupDepth bitfield,
causing silent miscompilation. Apparently some parser generators run into
this (see PR).
I don't know that that data structure is terribly size sensitive anyway,
and since there's no room to widen the bitfield, let's just use a separate
word in EHCatchScope for it.
Differential Revision: http://reviews.llvm.org/D21566
llvm-svn: 273434
diff --git a/clang/test/CodeGen/fixup-depth-overflow.c b/clang/test/CodeGen/fixup-depth-overflow.c
new file mode 100644
index 0000000..be8f542
--- /dev/null
+++ b/clang/test/CodeGen/fixup-depth-overflow.c
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -O1 -disable-llvm-optzns -emit-llvm -o - %s | FileCheck %s
+
+#define M if (x) goto L1;
+#define M10 M M M M M M M M M M
+#define M100 M10 M10 M10 M10 M10 M10 M10 M10 M10 M10
+#define M1000 M100 M100 M100 M100 M100 M100 M100 M100 M100 M100
+
+void f(int x) {
+ int h;
+
+ // Many gotos to not-yet-emitted labels would cause EHScope's FixupDepth
+ // to overflow (PR23490).
+ M1000 M1000 M1000
+
+ if (x == 5) {
+ // This will cause us to emit a clean-up of the stack variable. If the
+ // FixupDepths are broken, fixups will erroneously get threaded through it.
+ int i;
+ }
+
+L1:
+ return;
+}
+
+// CHECK-LABEL: define void @f
+// CHECK-NOT: cleanup