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, 2 insertions, 1 deletions

diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index c5405de902..7d5a7d3b7e 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -613,8 +613,8 @@ int main(int argc, char **argv) {
   initializeExpandGetElementPtrPass(Registry);
   initializeExpandSmallArgumentsPass(Registry);
   initializeExpandStructRegsPass(Registry);
-  initializeExpandTlsPass(Registry);
   initializeExpandTlsConstantExprPass(Registry);
+  initializeExpandTlsPass(Registry);
   initializeExpandVarArgsPass(Registry);
   initializeFlattenGlobalsPass(Registry);
   initializeGlobalCleanupPass(Registry);
@@ -626,6 +626,7 @@ int main(int argc, char **argv) {
   initializeReplacePtrsWithIntsPass(Registry);
   initializeResolveAliasesPass(Registry);
   initializeResolvePNaClIntrinsicsPass(Registry);
+  initializeRewriteAtomicsPass(Registry);
   initializeRewriteLLVMIntrinsicsPass(Registry);
   initializeRewritePNaClLibraryCallsPass(Registry);
   initializeStripAttributesPass(Registry);