[WebAssembly] Make returns variadic

Summary:
This is necessary and sufficient to get simple cases of multiple
return working with multivalue enabled. More complex cases will
require block and loop signatures to be generalized to potentially be
type indices as well.

Reviewers: aheejin, dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68684

llvm-svn: 374235

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
index 10327091aea3..fbccc58b13a6 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -1227,11 +1227,11 @@ getDepth(const SmallVectorImpl<const MachineBasicBlock *> &Stack,
 /// checks for such cases and fixes up the signatures.
 void WebAssemblyCFGStackify::fixEndsAtEndOfFunction(MachineFunction &MF) {
   const auto &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
-  assert(MFI.getResults().size() <= 1);
 
   if (MFI.getResults().empty())
     return;
 
+  // TODO: Generalize from value types to function types for multivalue
   WebAssembly::ExprType RetType;
   switch (MFI.getResults().front().SimpleTy) {
   case MVT::i32:
@@ -1266,10 +1266,14 @@ void WebAssemblyCFGStackify::fixEndsAtEndOfFunction(MachineFunction &MF) {
       if (MI.isPosition() || MI.isDebugInstr())
         continue;
       if (MI.getOpcode() == WebAssembly::END_BLOCK) {
+        if (MFI.getResults().size() > 1)
+          report_fatal_error("Multivalue block signatures not implemented yet");
         EndToBegin[&MI]->getOperand(0).setImm(int32_t(RetType));
         continue;
       }
       if (MI.getOpcode() == WebAssembly::END_LOOP) {
+        if (MFI.getResults().size() > 1)
+          report_fatal_error("Multivalue loop signatures not implemented yet");
         EndToBegin[&MI]->getOperand(0).setImm(int32_t(RetType));
         continue;
       }