[WebAssembly] Support for WebAssembly globals in LLVM IR

This patch adds support for WebAssembly globals in LLVM IR, representing
them as pointers to global values, in a non-default, non-integral
address space.  Instruction selection legalizes loads and stores to
these pointers to new WebAssemblyISD nodes GLOBAL_GET and GLOBAL_SET.
Once the lowering creates the new nodes, tablegen pattern matches those
and converts them to Wasm global.get/set of the appropriate type.

Based on work by Paulo Matos in https://reviews.llvm.org/D95425.

Reviewed By: pmatos

Differential Revision: https://reviews.llvm.org/D101608

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
index 68e4b9c..cb0cdf1 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFastISel.cpp
@@ -1182,6 +1182,8 @@ bool WebAssemblyFastISel::selectLoad(const Instruction *I) {
   const auto *Load = cast<LoadInst>(I);
   if (Load->isAtomic())
     return false;
+  if (!WebAssembly::isDefaultAddressSpace(Load->getPointerAddressSpace()))
+    return false;
   if (!Subtarget->hasSIMD128() && Load->getType()->isVectorTy())
     return false;
 
@@ -1240,6 +1242,8 @@ bool WebAssemblyFastISel::selectStore(const Instruction *I) {
   const auto *Store = cast<StoreInst>(I);
   if (Store->isAtomic())
     return false;
+  if (!WebAssembly::isDefaultAddressSpace(Store->getPointerAddressSpace()))
+    return false;
   if (!Subtarget->hasSIMD128() &&
       Store->getValueOperand()->getType()->isVectorTy())
     return false;