PNaCl: Add a pass to convert llvm.global_ctors to __init_array_start/end

This pass converts LLVM's special symbols llvm.global_ctors and
llvm.global_dtors to concrete arrays, __init_array_start/end and
__fini_array_start/end, that are usable by a C library.

The pass sorts the contents of global_ctors/dtors according to the
priority values they contain and removes the priority values.

This pass will allow us to simplify the PNaCl ABI so that less is done
at translation time.

BUG= http://code.google.com/p/nativeclient/issues/detail?id=3018
TEST=test/Transforms/NaCl/expand-ctors*.ll

Review URL: https://codereview.chromium.org/10977030

2 files changed, 22 insertions, 0 deletions

diff --git a/include/llvm/InitializePasses.h b/include/llvm/InitializePasses.h
index 4c93d480dd..87899fc360 100644
--- a/include/llvm/InitializePasses.h
+++ b/include/llvm/InitializePasses.h
@@ -261,6 +261,7 @@ void initializeUnpackMachineBundlesPass(PassRegistry&);
 void initializeFinalizeMachineBundlesPass(PassRegistry&);
 void initializeBBVectorizePass(PassRegistry&);
 void initializeMachineFunctionPrinterPassPass(PassRegistry&);
+void initializeExpandCtorsPass(PassRegistry&); // @LOCALMOD
 void initializeNaClCcRewritePass(PassRegistry&); // @LOCALMOD
 }
 
diff --git a/include/llvm/Transforms/NaCl.h b/include/llvm/Transforms/NaCl.h
new file mode 100644
index 0000000000..fe29463a8b
--- /dev/null
+++ b/include/llvm/Transforms/NaCl.h
@@ -0,0 +1,21 @@
+//===-- NaCl.h - NaCl Transformations ---------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_NACL_H
+#define LLVM_TRANSFORMS_NACL_H
+
+namespace llvm {
+
+class ModulePass;
+
+ModulePass *createExpandCtorsPass();
+
+}
+
+#endif