[WebAssembly] Implement eliminateCallFramePseudo

Summary:
Implement eliminateCallFramePsuedo to handle ADJCALLSTACKUP/DOWN
pseudo-instructions. Add a test calling a vararg function which causes non-0
adjustments. This revealed an issue with RegisterCoalescer wherein it
eliminates a COPY from SP32 to a vreg but failes to update the live ranges
of EXPR_STACK, causing a machineinstr verifier failure (so this test
is commented out).

Also add a dynamic alloca test, which causes a callseq_end dag node with
a 0 (instead of undef) second argument to be generated. We currently fail to
select that, so adjust the ADJCALLSTACKUP tablegen code to handle it.

Differential Revision: http://reviews.llvm.org/D15587

llvm-svn: 255844

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
index 3b219f4..41c8811 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
@@ -36,8 +36,12 @@ void WebAssemblyInstrInfo::copyPhysReg(MachineBasicBlock &MBB,
                                        MachineBasicBlock::iterator I,
                                        DebugLoc DL, unsigned DestReg,
                                        unsigned SrcReg, bool KillSrc) const {
-  const TargetRegisterClass *RC =
-      MBB.getParent()->getRegInfo().getRegClass(SrcReg);
+  // This method is called by post-RA expansion, which expects only pregs to
+  // exist. However we need to handle both here.
+  auto &MRI = MBB.getParent()->getRegInfo();
+  const TargetRegisterClass *RC = TargetRegisterInfo::isVirtualRegister(DestReg) ?
+      MRI.getRegClass(DestReg) :
+      MRI.getTargetRegisterInfo()->getMinimalPhysRegClass(SrcReg);
 
   unsigned CopyLocalOpcode;
   if (RC == &WebAssembly::I32RegClass)