1 files changed, 121 insertions, 0 deletions

diff --git a/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp b/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
new file mode 100644
index 000000000000..a1cc3e268e8f
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
@@ -0,0 +1,121 @@
+//===-- WebAssemblyWasmObjectWriter.cpp - WebAssembly Wasm Writer ---------===//
+//
+// 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 handles Wasm-specific object emission, converting LLVM's
+/// internal fixups into the appropriate relocations.
+///
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/WebAssemblyFixupKinds.h"
+#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
+#include "llvm/BinaryFormat/Wasm.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSectionWasm.h"
+#include "llvm/MC/MCSymbolWasm.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/MC/MCWasmObjectWriter.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace llvm;
+
+namespace {
+class WebAssemblyWasmObjectWriter final : public MCWasmObjectTargetWriter {
+public:
+  explicit WebAssemblyWasmObjectWriter(bool Is64Bit);
+
+private:
+  unsigned getRelocType(const MCValue &Target,
+                        const MCFixup &Fixup) const override;
+};
+} // end anonymous namespace
+
+WebAssemblyWasmObjectWriter::WebAssemblyWasmObjectWriter(bool Is64Bit)
+    : MCWasmObjectTargetWriter(Is64Bit) {}
+
+static const MCSection *getFixupSection(const MCExpr *Expr) {
+  if (auto SyExp = dyn_cast<MCSymbolRefExpr>(Expr)) {
+    if (SyExp->getSymbol().isInSection())
+      return &SyExp->getSymbol().getSection();
+    return nullptr;
+  }
+
+  if (auto BinOp = dyn_cast<MCBinaryExpr>(Expr)) {
+    auto SectionLHS = getFixupSection(BinOp->getLHS());
+    auto SectionRHS = getFixupSection(BinOp->getRHS());
+    return SectionLHS == SectionRHS ? nullptr : SectionLHS;
+  }
+
+  if (auto UnOp = dyn_cast<MCUnaryExpr>(Expr))
+    return getFixupSection(UnOp->getSubExpr());
+
+  return nullptr;
+}
+
+unsigned WebAssemblyWasmObjectWriter::getRelocType(const MCValue &Target,
+                                                   const MCFixup &Fixup) const {
+  const MCSymbolRefExpr *RefA = Target.getSymA();
+  assert(RefA);
+  auto& SymA = cast<MCSymbolWasm>(RefA->getSymbol());
+
+  MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
+
+  switch (Modifier) {
+    case MCSymbolRefExpr::VK_GOT:
+      return wasm::R_WASM_GLOBAL_INDEX_LEB;
+    case MCSymbolRefExpr::VK_WASM_TBREL:
+      assert(SymA.isFunction());
+      return wasm::R_WASM_TABLE_INDEX_REL_SLEB;
+    case MCSymbolRefExpr::VK_WASM_MBREL:
+      assert(SymA.isData());
+      return wasm::R_WASM_MEMORY_ADDR_REL_SLEB;
+    case MCSymbolRefExpr::VK_WASM_TYPEINDEX:
+      return wasm::R_WASM_TYPE_INDEX_LEB;
+    default:
+      break;
+  }
+
+  switch (unsigned(Fixup.getKind())) {
+  case WebAssembly::fixup_sleb128_i32:
+    if (SymA.isFunction())
+      return wasm::R_WASM_TABLE_INDEX_SLEB;
+    return wasm::R_WASM_MEMORY_ADDR_SLEB;
+  case WebAssembly::fixup_sleb128_i64:
+    llvm_unreachable("fixup_sleb128_i64 not implemented yet");
+  case WebAssembly::fixup_uleb128_i32:
+    if (SymA.isGlobal())
+      return wasm::R_WASM_GLOBAL_INDEX_LEB;
+    if (SymA.isFunction())
+      return wasm::R_WASM_FUNCTION_INDEX_LEB;
+    if (SymA.isEvent())
+      return wasm::R_WASM_EVENT_INDEX_LEB;
+    return wasm::R_WASM_MEMORY_ADDR_LEB;
+  case FK_Data_4:
+    if (SymA.isFunction())
+      return wasm::R_WASM_TABLE_INDEX_I32;
+    if (auto Section = static_cast<const MCSectionWasm *>(
+            getFixupSection(Fixup.getValue()))) {
+      if (Section->getKind().isText())
+        return wasm::R_WASM_FUNCTION_OFFSET_I32;
+      else if (!Section->isWasmData())
+        return wasm::R_WASM_SECTION_OFFSET_I32;
+    }
+    return wasm::R_WASM_MEMORY_ADDR_I32;
+  default:
+    llvm_unreachable("unimplemented fixup kind");
+  }
+}
+
+std::unique_ptr<MCObjectTargetWriter>
+llvm::createWebAssemblyWasmObjectWriter(bool Is64Bit) {
+  return llvm::make_unique<WebAssemblyWasmObjectWriter>(Is64Bit);
+}