1 files changed, 173 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/utils/TableGen/WebAssemblyDisassemblerEmitter.cpp b/contrib/llvm-project/llvm/utils/TableGen/WebAssemblyDisassemblerEmitter.cpp
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index 000000000000..54aa5a8164f2
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+++ b/contrib/llvm-project/llvm/utils/TableGen/WebAssemblyDisassemblerEmitter.cpp
@@ -0,0 +1,173 @@
+//===- WebAssemblyDisassemblerEmitter.cpp - Disassembler tables -*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the WebAssembly Disassembler Emitter.
+// It contains the implementation of the disassembler tables.
+// Documentation for the disassembler emitter in general can be found in
+// WebAssemblyDisassemblerEmitter.h.
+//
+//===----------------------------------------------------------------------===//
+
+#include "WebAssemblyDisassemblerEmitter.h"
+#include "llvm/TableGen/Record.h"
+
+namespace llvm {
+
+static constexpr int WebAssemblyInstructionTableSize = 256;
+
+void emitWebAssemblyDisassemblerTables(
+    raw_ostream &OS,
+    const ArrayRef<const CodeGenInstruction *> &NumberedInstructions) {
+  // First lets organize all opcodes by (prefix) byte. Prefix 0 is the
+  // starting table.
+  std::map<unsigned,
+           std::map<unsigned, std::pair<unsigned, const CodeGenInstruction *>>>
+      OpcodeTable;
+  for (unsigned I = 0; I != NumberedInstructions.size(); ++I) {
+    auto &CGI = *NumberedInstructions[I];
+    auto &Def = *CGI.TheDef;
+    if (!Def.getValue("Inst"))
+      continue;
+    auto &Inst = *Def.getValueAsBitsInit("Inst");
+    auto Opc = static_cast<unsigned>(
+        reinterpret_cast<IntInit *>(Inst.convertInitializerTo(IntRecTy::get()))
+            ->getValue());
+    if (Opc == 0xFFFFFFFF)
+      continue; // No opcode defined.
+    assert(Opc <= 0xFFFF);
+    auto Prefix = Opc >> 8;
+    Opc = Opc & 0xFF;
+    auto &CGIP = OpcodeTable[Prefix][Opc];
+    // All wasm instructions have a StackBased field of type string, we only
+    // want the instructions for which this is "true".
+    auto StackString =
+        Def.getValue("StackBased")->getValue()->getCastTo(StringRecTy::get());
+    auto IsStackBased =
+        StackString &&
+        reinterpret_cast<const StringInit *>(StackString)->getValue() == "true";
+    if (!IsStackBased)
+      continue;
+    if (CGIP.second) {
+      // We already have an instruction for this slot, so decide which one
+      // should be the canonical one. This determines which variant gets
+      // printed in a disassembly. We want e.g. "call" not "i32.call", and
+      // "end" when we don't know if its "end_loop" or "end_block" etc.
+      auto IsCanonicalExisting = CGIP.second->TheDef->getValue("IsCanonical")
+                                     ->getValue()
+                                     ->getAsString() == "1";
+      // We already have one marked explicitly as canonical, so keep it.
+      if (IsCanonicalExisting)
+        continue;
+      auto IsCanonicalNew =
+          Def.getValue("IsCanonical")->getValue()->getAsString() == "1";
+      // If the new one is explicitly marked as canonical, take it.
+      if (!IsCanonicalNew) {
+        // Neither the existing or new instruction is canonical.
+        // Pick the one with the shortest name as heuristic.
+        // Though ideally IsCanonical is always defined for at least one
+        // variant so this never has to apply.
+        if (CGIP.second->AsmString.size() <= CGI.AsmString.size())
+          continue;
+      }
+    }
+    // Set this instruction as the one to use.
+    CGIP = std::make_pair(I, &CGI);
+  }
+  OS << "#include \"MCTargetDesc/WebAssemblyMCTargetDesc.h\"\n";
+  OS << "\n";
+  OS << "namespace llvm {\n\n";
+  OS << "static constexpr int WebAssemblyInstructionTableSize = ";
+  OS << WebAssemblyInstructionTableSize << ";\n\n";
+  OS << "enum EntryType : uint8_t { ";
+  OS << "ET_Unused, ET_Prefix, ET_Instruction };\n\n";
+  OS << "struct WebAssemblyInstruction {\n";
+  OS << "  uint16_t Opcode;\n";
+  OS << "  EntryType ET;\n";
+  OS << "  uint8_t NumOperands;\n";
+  OS << "  uint16_t OperandStart;\n";
+  OS << "};\n\n";
+  std::vector<std::string> OperandTable, CurOperandList;
+  // Output one table per prefix.
+  for (auto &PrefixPair : OpcodeTable) {
+    if (PrefixPair.second.empty())
+      continue;
+    OS << "WebAssemblyInstruction InstructionTable" << PrefixPair.first;
+    OS << "[] = {\n";
+    for (unsigned I = 0; I < WebAssemblyInstructionTableSize; I++) {
+      auto InstIt = PrefixPair.second.find(I);
+      if (InstIt != PrefixPair.second.end()) {
+        // Regular instruction.
+        assert(InstIt->second.second);
+        auto &CGI = *InstIt->second.second;
+        OS << "  // 0x";
+        OS.write_hex(static_cast<unsigned long long>(I));
+        OS << ": " << CGI.AsmString << "\n";
+        OS << "  { " << InstIt->second.first << ", ET_Instruction, ";
+        OS << CGI.Operands.OperandList.size() << ", ";
+        // Collect operand types for storage in a shared list.
+        CurOperandList.clear();
+        for (auto &Op : CGI.Operands.OperandList) {
+          assert(Op.OperandType != "MCOI::OPERAND_UNKNOWN");
+          CurOperandList.push_back(Op.OperandType);
+        }
+        // See if we already have stored this sequence before. This is not
+        // strictly necessary but makes the table really small.
+        size_t OperandStart = OperandTable.size();
+        if (CurOperandList.size() <= OperandTable.size()) {
+          for (size_t J = 0; J <= OperandTable.size() - CurOperandList.size();
+               ++J) {
+            size_t K = 0;
+            for (; K < CurOperandList.size(); ++K) {
+              if (OperandTable[J + K] != CurOperandList[K]) break;
+            }
+            if (K == CurOperandList.size()) {
+              OperandStart = J;
+              break;
+            }
+          }
+        }
+        // Store operands if no prior occurrence.
+        if (OperandStart == OperandTable.size()) {
+          OperandTable.insert(OperandTable.end(), CurOperandList.begin(),
+                              CurOperandList.end());
+        }
+        OS << OperandStart;
+      } else {
+        auto PrefixIt = OpcodeTable.find(I);
+        // If we have a non-empty table for it that's not 0, this is a prefix.
+        if (PrefixIt != OpcodeTable.end() && I && !PrefixPair.first) {
+          OS << "  { 0, ET_Prefix, 0, 0";
+        } else {
+          OS << "  { 0, ET_Unused, 0, 0";
+        }
+      }
+      OS << "  },\n";
+    }
+    OS << "};\n\n";
+  }
+  // Create a table of all operands:
+  OS << "const uint8_t OperandTable[] = {\n";
+  for (auto &Op : OperandTable) {
+    OS << "  " << Op << ",\n";
+  }
+  OS << "};\n\n";
+  // Create a table of all extension tables:
+  OS << "struct { uint8_t Prefix; const WebAssemblyInstruction *Table; }\n";
+  OS << "PrefixTable[] = {\n";
+  for (auto &PrefixPair : OpcodeTable) {
+    if (PrefixPair.second.empty() || !PrefixPair.first)
+      continue;
+    OS << "  { " << PrefixPair.first << ", InstructionTable"
+       << PrefixPair.first;
+    OS << " },\n";
+  }
+  OS << "  { 0, nullptr }\n};\n\n";
+  OS << "} // end namespace llvm\n";
+}
+
+} // namespace llvm