[WebAssembly] Implement multivalue call_indirects

Summary:
Unlike normal calls, call_indirects have immediate arguments that
caused a MachineVerifier failure without a small tweak to loosen the
verifier's requirements for variadicOpsAreDefs instructions.

One nice thing about the new call_indirects is that they do not need
to participate in the PCALL_INDIRECT mechanism because their post-isel
hook handles moving the function pointer argument and adding the flags
and typeindex arguments itself.

Reviewers: aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D74191

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
index 5b77798..1e04438 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyUtilities.cpp
@@ -80,7 +80,7 @@ bool WebAssembly::mayThrow(const MachineInstr &MI) {
   return true;
 }
 
-inline const MachineOperand &getCalleeOp(const MachineInstr &MI) {
+const MachineOperand &WebAssembly::getCalleeOp(const MachineInstr &MI) {
   switch (MI.getOpcode()) {
   case WebAssembly::CALL_VOID:
   case WebAssembly::CALL_VOID_S:
@@ -138,7 +138,10 @@ inline const MachineOperand &getCalleeOp(const MachineInstr &MI) {
     return MI.getOperand(1);
   case WebAssembly::CALL:
   case WebAssembly::CALL_S:
-    return MI.getOperand(MI.getNumDefs());
+    return MI.getOperand(MI.getNumExplicitDefs());
+  case WebAssembly::CALL_INDIRECT:
+  case WebAssembly::CALL_INDIRECT_S:
+    return MI.getOperand(MI.getNumOperands() - 1);
   default:
     llvm_unreachable("Not a call instruction");
   }