Prevent alias from pointing to weak aliases.
This adds back r204781.
Original message:
Aliases are just another name for a position in a file. As such, the
regular symbol resolutions are not applied. For example, given
define void @my_func() {
ret void
}
@my_alias = alias weak void ()* @my_func
@my_alias2 = alias void ()* @my_alias
We produce without this patch:
.weak my_alias
my_alias = my_func
.globl my_alias2
my_alias2 = my_alias
That is, in the resulting ELF file my_alias, my_func and my_alias are
just 3 names pointing to offset 0 of .text. That is *not* the
semantics of IR linking. For example, linking in a
@my_alias = alias void ()* @other_func
would require the strong my_alias to override the weak one and
my_alias2 would end up pointing to other_func.
There is no way to represent that with aliases being just another
name, so the best solution seems to be to just disallow it, converting
a miscompile into an error.
llvm-svn: 204934
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index d216026..b8a0425 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -1463,8 +1463,8 @@
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(GA)) {
const GlobalValue *GValue = G->getGlobal();
const GlobalAlias *GAlias = dyn_cast<GlobalAlias>(GValue);
- const GlobalValue *RealGValue = GAlias ?
- GAlias->resolveAliasedGlobal(false) : GValue;
+ const GlobalValue *RealGValue =
+ GAlias ? GAlias->getAliasedGlobal() : GValue;
const GlobalVariable *GVar = dyn_cast<GlobalVariable>(RealGValue);
assert((GVar || isa<Function>(RealGValue)) &&
"Unexpected global value subclass!");