[WebAssembly] Add some comments. NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254096 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
index 29332940b76f39c6bc69e2b97fe132247f7196ae..c98bea9c21428292f5f60a81ac30eef8a28af987 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -187,7 +187,12 @@ void WebAssemblyPassConfig::addPostRegAlloc() {
 void WebAssemblyPassConfig::addPreSched2() {}
 
 void WebAssemblyPassConfig::addPreEmitPass() {
 void WebAssemblyPassConfig::addPreSched2() {}
 
 void WebAssemblyPassConfig::addPreEmitPass() {

+  // Put the CFG in structured form; insert BLOCK and LOOP markers.

   addPass(createWebAssemblyCFGStackify());
   addPass(createWebAssemblyCFGStackify());

+
+  // Create a mapping from LLVM CodeGen virtual registers to wasm registers.

   addPass(createWebAssemblyRegNumbering());
   addPass(createWebAssemblyRegNumbering());

+
+  // Perform the very last peephole optimizations on the code.

   addPass(createWebAssemblyPeephole());
 }
   addPass(createWebAssemblyPeephole());
 }