[WebAssembly] Add an option to make get_local/set_local explicit.

This patch adds a pass, controlled by an option and off by default for
now, for making implicit get_local/set_local explicit. This simplifies
emitting wasm with MC.

Differential Revision: https://reviews.llvm.org/D25836

llvm-svn: 285009

1 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
index e8fbe941345..f0f74e7b5e8 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -41,6 +41,11 @@ static cl::opt<bool> EnableEmSjLj(
     cl::desc("WebAssembly Emscripten-style setjmp/longjmp handling"),
     cl::init(false));
 
+static cl::opt<bool> ExplicitLocals(
+    "wasm-explicit-locals",
+    cl::desc("WebAssembly with explicit get_local/set_local"),
+    cl::init(false));
+
 extern "C" void LLVMInitializeWebAssemblyTarget() {
   // Register the target.
   RegisterTargetMachine<WebAssemblyTargetMachine> X(
@@ -256,6 +261,10 @@ void WebAssemblyPassConfig::addPreEmitPass() {
     addPass(createWebAssemblyRegColoring());
   }
 
+  // Insert explicit get_local and set_local operators.
+  if (ExplicitLocals)
+    addPass(createWebAssemblyExplicitLocals());
+
   // Eliminate multiple-entry loops.
   addPass(createWebAssemblyFixIrreducibleControlFlow());