tablegen: Generate GlobalISel match tables

1 files changed, 96 insertions, 0 deletions

diff --git a/backend/utils/TableGen/GlobalISelEmitter.cpp b/backend/utils/TableGen/GlobalISelEmitter.cpp
new file mode 100644
index 0000000..1634eb3
--- /dev/null
+++ b/backend/utils/TableGen/GlobalISelEmitter.cpp
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "TableGenBackends.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <ostream>
+#include <sstream>
+#include <string>
+#include <string_view>
+
+namespace rcc::targetgen {
+namespace {
+
+[[nodiscard]] std::string_view typeKindName(NormalizedSelectionTypeKind Kind) noexcept {
+  switch (Kind) {
+  case NormalizedSelectionTypeKind::Any:
+    return "Any";
+  case NormalizedSelectionTypeKind::Scalar:
+    return "Scalar";
+  case NormalizedSelectionTypeKind::Pointer:
+    return "Pointer";
+  }
+  return "Any";
+}
+
+void emitInstruction(std::ostream &Output, std::string_view Opcode, std::uint32_t OperandIndex,
+                     std::uint32_t Value = 0, std::string_view Auxiliary = "0",
+                     std::int64_t Immediate = 0) {
+  Output << "    {GIMatchTableOpcode::" << Opcode << ", " << OperandIndex << ", " << Value << ", "
+         << Auxiliary << ", " << Immediate << "},\n";
+}
+
+void emitTypePredicate(std::ostream &Output, std::uint32_t OperandIndex,
+                       const NormalizedSelectionTypePredicate &Predicate) {
+  emitInstruction(Output, "CheckOperandType", OperandIndex, Predicate.Bits,
+                  "static_cast<std::uint32_t>(GIMatchTypeKind::" +
+                      std::string(typeKindName(Predicate.Kind)) + ")");
+}
+
+[[nodiscard]] std::size_t instructionCount(const NormalizedSelectionRule &Rule) noexcept {
+  return 3U + (Rule.ResultType ? 1U : 0U) + Rule.OperandTypes.size() + Rule.OperandBanks.size() +
+         Rule.OperandClasses.size() + Rule.AppendedImmediates.size();
+}
+
+} // namespace
+
+std::string emitGlobalISel(const NormalizedTargetModel &Model, std::string_view SourceName) {
+  std::size_t InstructionCount = 0;
+  for (const NormalizedSelectionRule &Rule : Model.SelectionRules)
+    InstructionCount += instructionCount(Rule);
+
+  std::ostringstream Output;
+  Output << "// SPDX-License-Identifier: GPL-3.0-or-later\n\n";
+  Output << "// This file is generated by rcc-tblgen from ";
+  appendQuoted(Output, SourceName);
+  Output << ". Do not edit it manually.\n\n";
+  Output << "#ifdef GET_GLOBALISEL_MATCH_TABLE\n\n";
+  Output << "constexpr std::array<GIMatchTableInstruction, " << InstructionCount
+         << "> GeneratedGlobalISelInstructions = {{\n";
+  for (const NormalizedSelectionRule &Rule : Model.SelectionRules) {
+    emitInstruction(Output, "CheckOpcode", 0, Rule.MatchOpcode);
+    if (Rule.ResultType)
+      emitTypePredicate(Output, 0, *Rule.ResultType);
+    for (const NormalizedSelectionOperandTypePredicate &Predicate : Rule.OperandTypes)
+      emitTypePredicate(Output, Predicate.OperandIndex, Predicate.Type);
+    for (const NormalizedSelectionOperandBankPredicate &Predicate : Rule.OperandBanks)
+      emitInstruction(Output, "CheckOperandBank", Predicate.OperandIndex, Predicate.Bank);
+    for (const NormalizedSelectionOperandClassPredicate &Predicate : Rule.OperandClasses)
+      emitInstruction(Output, "CheckOperandClass", Predicate.OperandIndex, Predicate.RegClass);
+    emitInstruction(Output, "MutateOpcode", 0, Rule.ResultOpcode);
+    for (const std::int64_t Immediate : Rule.AppendedImmediates)
+      emitInstruction(Output, "AppendImmediate", 0, 0, "0", Immediate);
+    emitInstruction(Output, "Complete", 0);
+  }
+  Output << "}};\n\n";
+
+  Output << "constexpr std::array<GIMatchTableRule, " << Model.SelectionRules.size()
+         << "> GeneratedGlobalISelRules = {{\n";
+  std::size_t FirstInstruction = 0;
+  for (const NormalizedSelectionRule &Rule : Model.SelectionRules) {
+    const std::size_t Count = instructionCount(Rule);
+    Output << "    {";
+    appendQuoted(Output, Rule.Symbol);
+    Output << ", " << Rule.Priority << ", " << FirstInstruction << ", " << Count << "},\n";
+    FirstInstruction += Count;
+  }
+  Output << "}};\n\n";
+  Output << "[[nodiscard]] constexpr GIMatchTable generatedGlobalISelMatchTable() noexcept {\n"
+            "  return {GeneratedGlobalISelInstructions, GeneratedGlobalISelRules};\n"
+            "}\n\n";
+  Output << "#endif // GET_GLOBALISEL_MATCH_TABLE\n";
+  return Output.str();
+}
+
+} // namespace rcc::targetgen