[WebAssembly] Initial WebAssembly support in clang

This implements basic support for compiling (though not yet assembling
or linking) for a WebAssembly target. Note that ABI details are not yet
finalized, and may change.

Differential Revision: http://reviews.llvm.org/D12002

llvm-svn: 246814

1 files changed, 9 insertions, 3 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 6c79cfd678c..b9eefac2d9f 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -66,6 +66,7 @@ static CGCXXABI *createCXXABI(CodeGenModule &CGM) {
   case TargetCXXABI::iOS64:
   case TargetCXXABI::GenericMIPS:
   case TargetCXXABI::GenericItanium:
+  case TargetCXXABI::WebAssembly:
     return CreateItaniumCXXABI(CGM);
   case TargetCXXABI::Microsoft:
     return CreateMicrosoftCXXABI(CGM);
@@ -819,9 +820,14 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
   if (alignment)
     F->setAlignment(alignment);
 
-  // C++ ABI requires 2-byte alignment for member functions.
-  if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
-    F->setAlignment(2);
+  // Some C++ ABIs require 2-byte alignment for member functions, in order to
+  // reserve a bit for differentiating between virtual and non-virtual member
+  // functions. If the current target's C++ ABI requires this and this is a
+  // member function, set its alignment accordingly.
+  if (getTarget().getCXXABI().areMemberFunctionsAligned()) {
+    if (F->getAlignment() < 2 && isa<CXXMethodDecl>(D))
+      F->setAlignment(2);
+  }
 }
 
 void CodeGenModule::SetCommonAttributes(const Decl *D,