[WebAssembly] Handle debug information and virtual registers without crashing (reland r278967)

Summary: Currently, enabling debug information when compiling for WebAssembly crashes the backend. This commit fixes these by skipping debug values in backend passes.

Reviewers: jfb, aprantl, dschuff, echristo

Subscribers: llvm-commits, dschuff, jfb, MatzeB, dexonsmith, yurydelendik, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23635

llvm-svn: 279011

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp
index 11bda47eac5..1a83793b0d0 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp
@@ -88,6 +88,8 @@ bool WebAssemblyReplacePhysRegs::runOnMachineFunction(MachineFunction &MF) {
         if (VReg == WebAssembly::NoRegister)
           VReg = MRI.createVirtualRegister(RC);
         MO.setReg(VReg);
+        if (MO.getParent()->isDebugValue())
+          MO.setIsDebug();
         Changed = true;
       }
     }