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, 91 insertions, 0 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
new file mode 100644
index 00000000000..7a6c7784c54
--- /dev/null
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -0,0 +1,91 @@
+//===-- WebAssemblyAsmPrinter.cpp - WebAssembly LLVM assembly writer ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file contains a printer that converts from our internal
+/// representation of machine-dependent LLVM code to the WebAssembly assembly
+/// language.
+///
+//===----------------------------------------------------------------------===//
+
+#include "WebAssembly.h"
+#include "WebAssemblyMachineFunctionInfo.h"
+#include "WebAssemblyRegisterInfo.h"
+#include "WebAssemblySubtarget.h"
+#include "InstPrinter/WebAssemblyInstPrinter.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+
+#include "llvm/ADT/SmallString.h"
+#include "llvm/CodeGen/AsmPrinter.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "asm-printer"
+
+namespace {
+
+class WebAssemblyAsmPrinter final : public AsmPrinter {
+public:
+  WebAssemblyAsmPrinter(TargetMachine &TM, std::unique_ptr<MCStreamer> Streamer)
+      : AsmPrinter(TM, std::move(Streamer)) {}
+
+private:
+  const char *getPassName() const override {
+    return "WebAssembly Assembly Printer";
+  }
+
+  //===------------------------------------------------------------------===//
+  // MachineFunctionPass Implementation.
+  //===------------------------------------------------------------------===//
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AsmPrinter::getAnalysisUsage(AU);
+  }
+
+  bool runOnMachineFunction(MachineFunction &F) override {
+    return AsmPrinter::runOnMachineFunction(F);
+  }
+
+  //===------------------------------------------------------------------===//
+  // AsmPrinter Implementation.
+  //===------------------------------------------------------------------===//
+
+  void EmitInstruction(const MachineInstr *MI) override;
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+
+void WebAssemblyAsmPrinter::EmitInstruction(const MachineInstr *MI) {
+  SmallString<128> Str;
+  raw_svector_ostream OS(Str);
+
+  switch (MI->getOpcode()) {
+  default:
+    DEBUG(MI->print(dbgs()));
+    llvm_unreachable("Unhandled instruction");
+    break;
+  }
+
+  OutStreamer->EmitRawText(OS.str());
+}
+
+// Force static initialization.
+extern "C" void LLVMInitializeWebAssemblyAsmPrinter() {
+  RegisterAsmPrinter<WebAssemblyAsmPrinter> X(TheWebAssemblyTarget32);
+  RegisterAsmPrinter<WebAssemblyAsmPrinter> Y(TheWebAssemblyTarget64);
+}