[WebAssembly] Use named operands to identify loads and stores

Summary:
Uses the named operands tablegen feature to look up the indices of
offset, address, and p2align operands for all load and store
instructions. This replaces brittle, incorrect logic for identifying
loads and store when eliminating frame indices, which previously
crashed on bulk-memory ops. It also cleans up the SetP2Alignment pass.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59007

llvm-svn: 355770

1 files changed, 8 insertions, 5 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
index ae808dd6597..d0002d9e10f 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
@@ -70,13 +70,16 @@ void WebAssemblyRegisterInfo::eliminateFrameIndex(
 
   // If this is the address operand of a load or store, make it relative to SP
   // and fold the frame offset directly in.
-  if ((MI.mayLoad() && FIOperandNum == WebAssembly::LoadAddressOperandNo) ||
-      (MI.mayStore() && FIOperandNum == WebAssembly::StoreAddressOperandNo)) {
-    assert(FrameOffset >= 0 && MI.getOperand(FIOperandNum - 1).getImm() >= 0);
-    int64_t Offset = MI.getOperand(FIOperandNum - 1).getImm() + FrameOffset;
+  unsigned AddrOperandNum = WebAssembly::getNamedOperandIdx(
+      MI.getOpcode(), WebAssembly::OpName::addr);
+  if (AddrOperandNum == FIOperandNum) {
+    unsigned OffsetOperandNum = WebAssembly::getNamedOperandIdx(
+        MI.getOpcode(), WebAssembly::OpName::off);
+    assert(FrameOffset >= 0 && MI.getOperand(OffsetOperandNum).getImm() >= 0);
+    int64_t Offset = MI.getOperand(OffsetOperandNum).getImm() + FrameOffset;
 
     if (static_cast<uint64_t>(Offset) <= std::numeric_limits<uint32_t>::max()) {
-      MI.getOperand(FIOperandNum - 1).setImm(Offset);
+      MI.getOperand(OffsetOperandNum).setImm(Offset);
       MI.getOperand(FIOperandNum)
           .ChangeToRegister(FrameRegister, /*IsDef=*/false);
       return;