Concurrency support for PNaCl ABI

Add portable support for concurrency in PNaCl's ABI:
 - Promote volatile to atomic.
 - Promote all memory ordering to sequential consistency.
 - Rewrite all atomic operations to frozen NaCl intrinsics for pexe.
 - Rewrite atomic intrinsics to LLVM instructions for translation.

This change also adds documentation to the PNaCl language reference, as
well as tests where it makes sense.

A future CL could clean up more of our code which mentions atomics,
volatiles, memory orderings.

Multiple reviewers because this is a big patch:
 - eliben: LLVM-fu and ResolvePNaClIntrinsics.
 - dschuff: ABI stability.
 - mseaborn: ABI stability.
 - sehr: Tron-duty (fight for the user's programs to work).

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3475
R=dschuff@chromium.org, eliben@chromium.org, sehr@google.com
TEST= (cd ./pnacl/build/llvm_x86_64; ninja check-all) && ./pnacl/test.sh test-x86-32 && ./pnacl/test.sh test-x86-64 && ./pnacl/test.sh test-arm && ./pnacl/test.sh test-x86-32-sbtc && ./pnacl/test.sh test-x86-64-sbtc && ./pnacl/test.sh test-arm-sbtc

Review URL: https://codereview.chromium.org/17777004

1 files changed, 9 insertions, 8 deletions

diff --git a/include/llvm/Transforms/NaCl.h b/include/llvm/Transforms/NaCl.h
index 43adb237dd..ec1a54aaa8 100644
--- a/include/llvm/Transforms/NaCl.h
+++ b/include/llvm/Transforms/NaCl.h
@@ -22,30 +22,31 @@ class PassManager;
 class Use;
 class Value;
 
+BasicBlockPass *createExpandGetElementPtrPass();
+BasicBlockPass *createPromoteI1OpsPass();
+FunctionPass *createExpandConstantExprPass();
+FunctionPass *createExpandStructRegsPass();
+FunctionPass *createInsertDivideCheckPass();
+FunctionPass *createPromoteIntegersPass();
+FunctionPass *createResolvePNaClIntrinsicsPass();
 ModulePass *createAddPNaClExternalDeclsPass();
 ModulePass *createCanonicalizeMemIntrinsicsPass();
 ModulePass *createExpandArithWithOverflowPass();
 ModulePass *createExpandByValPass();
-FunctionPass *createExpandConstantExprPass();
 ModulePass *createExpandCtorsPass();
-BasicBlockPass *createExpandGetElementPtrPass();
 ModulePass *createExpandSmallArgumentsPass();
-FunctionPass *createExpandStructRegsPass();
-ModulePass *createExpandTlsPass();
 ModulePass *createExpandTlsConstantExprPass();
+ModulePass *createExpandTlsPass();
 ModulePass *createExpandVarArgsPass();
 ModulePass *createFlattenGlobalsPass();
 ModulePass *createGlobalCleanupPass();
-BasicBlockPass *createPromoteI1OpsPass();
-FunctionPass *createPromoteIntegersPass();
 ModulePass *createReplacePtrsWithIntsPass();
 ModulePass *createResolveAliasesPass();
-FunctionPass *createResolvePNaClIntrinsicsPass();
+ModulePass *createRewriteAtomicsPass();
 ModulePass *createRewriteLLVMIntrinsicsPass();
 ModulePass *createRewritePNaClLibraryCallsPass();
 ModulePass *createStripAttributesPass();
 ModulePass *createStripMetadataPass();
-FunctionPass *createInsertDivideCheckPass();
 
 void PNaClABISimplifyAddPreOptPasses(PassManager &PM);
 void PNaClABISimplifyAddPostOptPasses(PassManager &PM);