[WebAssembly] Handle debug information and virtual registers without crashing

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

Differential Revision: https://reviews.llvm.org/D21808

llvm-svn: 278967

3 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
index aa40098f246..fba1fdab140 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
@@ -255,7 +255,7 @@ static bool HasOneUse(unsigned Reg, MachineInstr *Def,
   const VNInfo *DefVNI = LI.getVNInfoAt(
       LIS.getInstructionIndex(*Def).getRegSlot());
   assert(DefVNI);
-  for (auto I : MRI.use_nodbg_operands(Reg)) {
+  for (auto &I : MRI.use_nodbg_operands(Reg)) {
     const auto &Result = LI.Query(LIS.getInstructionIndex(*I.getParent()));
     if (Result.valueIn() == DefVNI) {
       if (!Result.isKill())
@@ -360,7 +360,7 @@ static bool OneUseDominatesOtherUses(unsigned Reg, const MachineOperand &OneUse,
   const MachineInstr *OneUseInst = OneUse.getParent();
   VNInfo *OneUseVNI = LI.getVNInfoBefore(LIS.getInstructionIndex(*OneUseInst));
 
-  for (const MachineOperand &Use : MRI.use_operands(Reg)) {
+  for (const MachineOperand &Use : MRI.use_nodbg_operands(Reg)) {
     if (&Use == &OneUse)
       continue;
 
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;
       }
     }
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp
index 1e9a773ae62..eb157ddd700 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp
@@ -90,7 +90,7 @@ static bool ReplaceDominatedUses(MachineBasicBlock &MBB, MachineInstr &MI,
 
   SmallVector<SlotIndex, 4> Indices;
 
-  for (auto I = MRI.use_begin(FromReg), E = MRI.use_end(); I != E;) {
+  for (auto I = MRI.use_nodbg_begin(FromReg), E = MRI.use_nodbg_end(); I != E;) {
     MachineOperand &O = *I++;
     MachineInstr *Where = O.getParent();