1 files changed, 152 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/contrib/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
new file mode 100644
index 000000000000..77744e53d62f
--- /dev/null
+++ b/contrib/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -0,0 +1,152 @@
+//=- WebAssemblyMCCodeEmitter.cpp - Convert WebAssembly code to machine code -//
+//
+//                     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 implements the WebAssemblyMCCodeEmitter class.
+///
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/WebAssemblyFixupKinds.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/EndianStream.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+#define DEBUG_TYPE "mccodeemitter"
+
+STATISTIC(MCNumEmitted, "Number of MC instructions emitted.");
+STATISTIC(MCNumFixups, "Number of MC fixups created.");
+
+namespace {
+class WebAssemblyMCCodeEmitter final : public MCCodeEmitter {
+  const MCInstrInfo &MCII;
+
+  // Implementation generated by tablegen.
+  uint64_t getBinaryCodeForInstr(const MCInst &MI,
+                                 SmallVectorImpl<MCFixup> &Fixups,
+                                 const MCSubtargetInfo &STI) const;
+
+  void encodeInstruction(const MCInst &MI, raw_ostream &OS,
+                         SmallVectorImpl<MCFixup> &Fixups,
+                         const MCSubtargetInfo &STI) const override;
+
+public:
+  WebAssemblyMCCodeEmitter(const MCInstrInfo &mcii) : MCII(mcii) {}
+};
+} // end anonymous namespace
+
+MCCodeEmitter *llvm::createWebAssemblyMCCodeEmitter(const MCInstrInfo &MCII) {
+  return new WebAssemblyMCCodeEmitter(MCII);
+}
+
+void WebAssemblyMCCodeEmitter::encodeInstruction(
+    const MCInst &MI, raw_ostream &OS, SmallVectorImpl<MCFixup> &Fixups,
+    const MCSubtargetInfo &STI) const {
+  uint64_t Start = OS.tell();
+
+  uint64_t Binary = getBinaryCodeForInstr(MI, Fixups, STI);
+  if (Binary <= UINT8_MAX) {
+    OS << uint8_t(Binary);
+  } else {
+    assert(Binary <= UINT16_MAX && "Several-byte opcodes not supported yet");
+    OS << uint8_t(Binary >> 8)
+       << uint8_t(Binary);
+  }
+
+  // For br_table instructions, encode the size of the table. In the MCInst,
+  // there's an index operand, one operand for each table entry, and the
+  // default operand.
+  if (MI.getOpcode() == WebAssembly::BR_TABLE_I32 ||
+      MI.getOpcode() == WebAssembly::BR_TABLE_I64)
+    encodeULEB128(MI.getNumOperands() - 2, OS);
+
+  const MCInstrDesc &Desc = MCII.get(MI.getOpcode());
+  for (unsigned i = 0, e = MI.getNumOperands(); i < e; ++i) {
+    const MCOperand &MO = MI.getOperand(i);
+    if (MO.isReg()) {
+      /* nothing to encode */
+    } else if (MO.isImm()) {
+      if (i < Desc.getNumOperands()) {
+        assert(Desc.TSFlags == 0 &&
+               "WebAssembly non-variable_ops don't use TSFlags");
+        const MCOperandInfo &Info = Desc.OpInfo[i];
+        if (Info.OperandType == WebAssembly::OPERAND_I32IMM) {
+          encodeSLEB128(int32_t(MO.getImm()), OS);
+        } else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
+          encodeSLEB128(int64_t(MO.getImm()), OS);
+        } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
+          llvm_unreachable("wasm globals should only be accessed symbolicly");
+        } else if (Info.OperandType == WebAssembly::OPERAND_SIGNATURE) {
+          encodeSLEB128(int64_t(MO.getImm()), OS);
+        } else {
+          encodeULEB128(uint64_t(MO.getImm()), OS);
+        }
+      } else {
+        assert(Desc.TSFlags == (WebAssemblyII::VariableOpIsImmediate |
+                                WebAssemblyII::VariableOpImmediateIsLabel));
+        encodeULEB128(uint64_t(MO.getImm()), OS);
+      }
+    } else if (MO.isFPImm()) {
+      assert(i < Desc.getNumOperands() &&
+             "Unexpected floating-point immediate as a non-fixed operand");
+      assert(Desc.TSFlags == 0 &&
+             "WebAssembly variable_ops floating point ops don't use TSFlags");
+      const MCOperandInfo &Info = Desc.OpInfo[i];
+      if (Info.OperandType == WebAssembly::OPERAND_F32IMM) {
+        // TODO: MC converts all floating point immediate operands to double.
+        // This is fine for numeric values, but may cause NaNs to change bits.
+        float f = float(MO.getFPImm());
+        support::endian::Writer<support::little>(OS).write<float>(f);
+      } else {
+        assert(Info.OperandType == WebAssembly::OPERAND_F64IMM);
+        double d = MO.getFPImm();
+        support::endian::Writer<support::little>(OS).write<double>(d);
+      }
+    } else if (MO.isExpr()) {
+      const MCOperandInfo &Info = Desc.OpInfo[i];
+      llvm::MCFixupKind FixupKind;
+      size_t PaddedSize = 5;
+      if (Info.OperandType == WebAssembly::OPERAND_I32IMM) {
+        FixupKind = MCFixupKind(WebAssembly::fixup_code_sleb128_i32);
+      } else if (Info.OperandType == WebAssembly::OPERAND_I64IMM) {
+        FixupKind = MCFixupKind(WebAssembly::fixup_code_sleb128_i64);
+        PaddedSize = 10;
+      } else if (Info.OperandType == WebAssembly::OPERAND_FUNCTION32 ||
+                 Info.OperandType == WebAssembly::OPERAND_OFFSET32 ||
+                 Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {
+        FixupKind = MCFixupKind(WebAssembly::fixup_code_uleb128_i32);
+      } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
+        FixupKind = MCFixupKind(WebAssembly::fixup_code_global_index);
+      } else {
+        llvm_unreachable("unexpected symbolic operand kind");
+      }
+      Fixups.push_back(MCFixup::create(
+          OS.tell() - Start, MO.getExpr(),
+          FixupKind, MI.getLoc()));
+      ++MCNumFixups;
+      encodeULEB128(0, OS, PaddedSize);
+    } else {
+      llvm_unreachable("unexpected operand kind");
+    }
+  }
+
+  ++MCNumEmitted; // Keep track of the # of mi's emitted.
+}
+
+#include "WebAssemblyGenMCCodeEmitter.inc"