[WebAssembly] Define the atomic type sizes

WebAssembly's spec has now been updated to specify some guarantees
about lock free atomic accesses. Update clang to match.

This also updates sig_atomic_t to be 64-bit on wasm64. WebAssembly
does not presently have asynchronous interrupts, but this change is
within the spirit of how they will work if they are added.

Differential Revision: http://reviews.llvm.org/D12862

llvm-svn: 247624

1 files changed, 3 insertions, 4 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 2007f01c2ad..35d7030a250 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -6994,6 +6994,7 @@ public:
     LargeArrayMinWidth = 128;
     LargeArrayAlign = 128;
     SimdDefaultAlign = 128;
+    SigAtomicType = SignedLong;
   }
 
 protected:
@@ -7096,8 +7097,7 @@ class WebAssembly32TargetInfo : public WebAssemblyTargetInfo {
 public:
   explicit WebAssembly32TargetInfo(const llvm::Triple &T)
       : WebAssemblyTargetInfo(T) {
-    // TODO: Set this to the correct value once the spec issues are resolved.
-    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
+    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 32;
     DataLayoutString = "e-p:32:32-i64:64-n32:64-S128";
   }
 
@@ -7115,8 +7115,7 @@ public:
       : WebAssemblyTargetInfo(T) {
     LongAlign = LongWidth = 64;
     PointerAlign = PointerWidth = 64;
-    // TODO: Set this to the correct value once the spec issues are resolved.
-    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 0;
+    MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64;
     DataLayoutString = "e-p:64:64-i64:64-n32:64-S128";
   }