WebAssembly: basic bitcode → assembly CodeGen test

Summary:
Add a basic CodeGen bitcode test which (for now) only prints out the function name and nothing else. The current code merely implements the basic needed for the test run to not crash / assert. Getting to that point required:

 - Basic InstPrinter.
 - Basic AsmPrinter.
 - DiagnosticInfoUnsupported (not strictly required, but nice to have, duplicated from AMDGPU/BPF's ISelLowering).
 - Some SP and register setup in WebAssemblyTargetLowering.
 - Basic LowerFormalArguments.
 - GenInstrInfo.
 - Placeholder LowerFormalArguments.
 - Placeholder CanLowerReturn and LowerReturn.
 - Basic DAGToDAGISel::Select, which requiresGenDAGISel.inc as well as GET_INSTRINFO_ENUM with GenInstrInfo.inc.
 - Remove WebAssemblyFrameLowering::determineCalleeSaves and rely on default.
 - Implement WebAssemblyFrameLowering::hasFP, same as AArch64's implementation.

Follow-up patches will implement a real AsmPrinter, which will require adding MI opcodes specific to WebAssembly.

Reviewers: sunfish

Subscribers: aemerson, jfb, llvm-commits

Differential Revision: http://reviews.llvm.org/D11369

llvm-svn: 242939

1 files changed, 7 insertions, 8 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
index 3d9050a..fec9455 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
@@ -39,7 +39,12 @@ using namespace llvm;
 /// Return true if the specified function should have a dedicated frame pointer
 /// register.
 bool WebAssemblyFrameLowering::hasFP(const MachineFunction &MF) const {
-  llvm_unreachable("TODO: implement hasFP");
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  const auto *RegInfo = static_cast<const WebAssemblyRegisterInfo *>(
+      MF.getSubtarget().getRegisterInfo());
+  return MFI->hasCalls() || MFI->hasVarSizedObjects() ||
+         MFI->isFrameAddressTaken() || MFI->hasStackMap() ||
+         MFI->hasPatchPoint() || RegInfo->needsStackRealignment(MF);
 }
 
 /// Under normal circumstances, when a frame pointer is not required, we reserve
@@ -60,16 +65,10 @@ void WebAssemblyFrameLowering::eliminateCallFramePseudoInstr(
 
 void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
                                             MachineBasicBlock &MBB) const {
-  llvm_unreachable("TODO: implement emitPrologue");
+  // FIXME: Implement WebAssemblyFrameLowering::emitPrologue.
 }
 
 void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
                                             MachineBasicBlock &MBB) const {
   llvm_unreachable("TODO: implement emitEpilogue");
 }
-
-void WebAssemblyFrameLowering::determineCalleeSaves(MachineFunction &MF,
-                                                    BitVector &SavedRegs,
-                                                    RegScavenger *RS) const {
-  llvm_unreachable("TODO: implement determineCalleeSaves");
-}