1 files changed, 122 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyAsmBackend.cpp b/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyAsmBackend.cpp
new file mode 100644
index 000000000000..a468022044bd
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyAsmBackend.cpp
@@ -0,0 +1,122 @@
+//===-- WebAssemblyAsmBackend.cpp - WebAssembly Assembler Backend ---------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements the WebAssemblyAsmBackend class.
+///
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/WebAssemblyFixupKinds.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCWasmObjectWriter.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+
+class WebAssemblyAsmBackend final : public MCAsmBackend {
+  bool Is64Bit;
+  bool IsEmscripten;
+
+public:
+  explicit WebAssemblyAsmBackend(bool Is64Bit, bool IsEmscripten)
+      : MCAsmBackend(llvm::endianness::little), Is64Bit(Is64Bit),
+        IsEmscripten(IsEmscripten) {}
+
+  unsigned getNumFixupKinds() const override {
+    return WebAssembly::NumTargetFixupKinds;
+  }
+
+  const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const override;
+
+  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
+                  const MCValue &Target, MutableArrayRef<char> Data,
+                  uint64_t Value, bool IsPCRel,
+                  const MCSubtargetInfo *STI) const override;
+
+  std::unique_ptr<MCObjectTargetWriter>
+  createObjectTargetWriter() const override;
+
+  bool writeNopData(raw_ostream &OS, uint64_t Count,
+                    const MCSubtargetInfo *STI) const override;
+};
+
+const MCFixupKindInfo &
+WebAssemblyAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
+  const static MCFixupKindInfo Infos[WebAssembly::NumTargetFixupKinds] = {
+      // This table *must* be in the order that the fixup_* kinds are defined in
+      // WebAssemblyFixupKinds.h.
+      //
+      // Name                     Offset (bits) Size (bits)     Flags
+      {"fixup_sleb128_i32", 0, 5 * 8, 0},
+      {"fixup_sleb128_i64", 0, 10 * 8, 0},
+      {"fixup_uleb128_i32", 0, 5 * 8, 0},
+      {"fixup_uleb128_i64", 0, 10 * 8, 0},
+  };
+
+  if (Kind < FirstTargetFixupKind)
+    return MCAsmBackend::getFixupKindInfo(Kind);
+
+  assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() &&
+         "Invalid kind!");
+  return Infos[Kind - FirstTargetFixupKind];
+}
+
+bool WebAssemblyAsmBackend::writeNopData(raw_ostream &OS, uint64_t Count,
+                                         const MCSubtargetInfo *STI) const {
+  for (uint64_t I = 0; I < Count; ++I)
+    OS << char(WebAssembly::Nop);
+
+  return true;
+}
+
+void WebAssemblyAsmBackend::applyFixup(const MCAssembler &Asm,
+                                       const MCFixup &Fixup,
+                                       const MCValue &Target,
+                                       MutableArrayRef<char> Data,
+                                       uint64_t Value, bool IsPCRel,
+                                       const MCSubtargetInfo *STI) const {
+  const MCFixupKindInfo &Info = getFixupKindInfo(Fixup.getKind());
+  assert(Info.Flags == 0 && "WebAssembly does not use MCFixupKindInfo flags");
+
+  unsigned NumBytes = alignTo(Info.TargetSize, 8) / 8;
+  if (Value == 0)
+    return; // Doesn't change encoding.
+
+  // Shift the value into position.
+  Value <<= Info.TargetOffset;
+
+  unsigned Offset = Fixup.getOffset();
+  assert(Offset + NumBytes <= Data.size() && "Invalid fixup offset!");
+
+  // For each byte of the fragment that the fixup touches, mask in the
+  // bits from the fixup value.
+  for (unsigned I = 0; I != NumBytes; ++I)
+    Data[Offset + I] |= uint8_t((Value >> (I * 8)) & 0xff);
+}
+
+std::unique_ptr<MCObjectTargetWriter>
+WebAssemblyAsmBackend::createObjectTargetWriter() const {
+  return createWebAssemblyWasmObjectWriter(Is64Bit, IsEmscripten);
+}
+
+} // end anonymous namespace
+
+MCAsmBackend *llvm::createWebAssemblyAsmBackend(const Triple &TT) {
+  return new WebAssemblyAsmBackend(TT.isArch64Bit(), TT.isOSEmscripten());
+}