PNaCl: Fix ExpandTls to handle GlobalAliases of thread-local variables

Expand out these aliases in the ExpandTlsConstantExpr pass.

BUG=https://code.google.com/p/nativeclient/issues/detail?id=3347
TEST=test/Transforms/NaCl/expand-tls-constexpr-alias.ll

Review URL: https://codereview.chromium.org/12989011

2 files changed, 36 insertions, 0 deletions

diff --git a/lib/Transforms/NaCl/ExpandTlsConstantExpr.cpp b/lib/Transforms/NaCl/ExpandTlsConstantExpr.cpp
index 45612b2616..51b21cbf2a 100644
--- a/lib/Transforms/NaCl/ExpandTlsConstantExpr.cpp
+++ b/lib/Transforms/NaCl/ExpandTlsConstantExpr.cpp
@@ -95,6 +95,14 @@ static void expandConstExpr(Constant *Expr) {
 }
 
 bool ExpandTlsConstantExpr::runOnModule(Module &M) {
+  for (Module::alias_iterator Iter = M.alias_begin();
+       Iter != M.alias_end(); ) {
+    GlobalAlias *GA = Iter++;
+    if (GA->isThreadDependent()) {
+      GA->replaceAllUsesWith(GA->getAliasee());
+      GA->eraseFromParent();
+    }
+  }
   for (Module::global_iterator Global = M.global_begin();
        Global != M.global_end();
        ++Global) {
diff --git a/test/Transforms/NaCl/expand-tls-constexpr-alias.ll b/test/Transforms/NaCl/expand-tls-constexpr-alias.ll
new file mode 100644
index 0000000000..65daa5eacd
--- /dev/null
+++ b/test/Transforms/NaCl/expand-tls-constexpr-alias.ll
@@ -0,0 +1,28 @@
+; RUN: opt < %s -nacl-expand-tls-constant-expr -S | FileCheck %s
+
+@real_tvar = thread_local global i32 123
+@tvar_alias = alias i32* @real_tvar
+@tvar_alias2 = alias i32* getelementptr (i32* @real_tvar, i32 100)
+
+
+define i32* @get_tvar() {
+  ret i32* @tvar_alias
+}
+; CHECK: define i32* @get_tvar()
+; CHECK: ret i32* @real_tvar
+
+
+define i32* @get_tvar2() {
+  ret i32* @tvar_alias2
+}
+; CHECK: define i32* @get_tvar2()
+; CHECK: %expanded = getelementptr i32* @real_tvar, i32 100
+; CHECK: ret i32* %expanded
+
+
+define i32* @get_tvar3() {
+  ret i32* getelementptr (i32* @tvar_alias2, i32 100)
+}
+; CHECK: define i32* @get_tvar3()
+; CHECK: %expanded = getelementptr i32* @real_tvar, i32 200
+; CHECK: ret i32* %expanded