[RISCV] Generate MC pseudo lowering

4 files changed, 146 insertions, 7 deletions

diff --git a/backend/utils/TableGen/Common/CodeGenInstruction.cpp b/backend/utils/TableGen/Common/CodeGenInstruction.cpp
index 61c72a2..45b597c 100644
--- a/backend/utils/TableGen/Common/CodeGenInstruction.cpp
+++ b/backend/utils/TableGen/Common/CodeGenInstruction.cpp
@@ -388,13 +388,10 @@ CodeGenTarget::normalizeImplicitRegisters(const std::vector<SourceImplicitRegist
                                    HasEncodingCategory || HasAssemblyFormat;
     const bool IsPseudoSource =
         std::ranges::find(Instruction.Flags, "pseudo") != Instruction.Flags.end();
-    const bool IsTerminalEmissionSource =
-        std::ranges::find(Instruction.Flags, "terminal_emission") != Instruction.Flags.end();
-    if (HasAnyMachineFact != HasAllMachineFacts ||
-        ((!IsPseudoSource || IsTerminalEmissionSource) && !HasAllMachineFacts)) {
+    if ((!IsPseudoSource && !HasAllMachineFacts) || HasAnyMachineFact != HasAllMachineFacts) {
       fail(Instruction.Range,
-           "encoded instructions and terminal-emission pseudos require complete scheduling, "
-           "encoding, mnemonic, and assembly-format facts");
+           "encoded instructions require complete scheduling, encoding, mnemonic, and "
+           "assembly-format facts");
       return false;
     }
     const auto SchedulingClass = SchedulingClassBySymbol.find(Instruction.SchedulingClassSymbol);
diff --git a/backend/utils/TableGen/Common/CodeGenMCPseudoLowering.cpp b/backend/utils/TableGen/Common/CodeGenMCPseudoLowering.cpp
new file mode 100644
index 0000000..49ec2a6
--- /dev/null
+++ b/backend/utils/TableGen/Common/CodeGenMCPseudoLowering.cpp
@@ -0,0 +1,121 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "CodeGenTarget.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <ranges>
+#include <string_view>
+#include <unordered_set>
+
+namespace rcc::targetgen {
+namespace {
+
+[[nodiscard]] const NormalizedInstruction *findInstruction(const NormalizedTargetModel &Model,
+                                                           std::string_view Symbol) noexcept {
+  const auto Position =
+      std::ranges::find(Model.Instructions, Symbol, &NormalizedInstruction::Symbol);
+  return Position == Model.Instructions.end() ? nullptr : &*Position;
+}
+
+[[nodiscard]] bool hasFlag(const NormalizedInstruction &Instruction,
+                           std::string_view Flag) noexcept {
+  return std::ranges::contains(Instruction.Flags, Flag);
+}
+
+[[nodiscard]] bool hasCompatibleKind(const NormalizedOperand &Source,
+                                     const NormalizedOperand &Result) noexcept {
+  return std::ranges::any_of(Source.Kinds, [&Result](const std::string &Kind) {
+    return std::ranges::contains(Result.Kinds, Kind);
+  });
+}
+
+} // namespace
+
+bool CodeGenTarget::normalizeMCPseudoExpansions(NormalizedTargetModel &Result) {
+  std::unordered_set<std::uint32_t> PseudoOpcodes;
+  for (const SourceMCPseudoExpansion &Expansion : Input.MCPseudoExpansions) {
+    const NormalizedInstruction *Pseudo = findInstruction(Result, Expansion.PseudoOpcodeSymbol);
+    const NormalizedInstruction *ResultInstruction =
+        findInstruction(Result, Expansion.ResultOpcodeSymbol);
+    if (Pseudo == nullptr || ResultInstruction == nullptr ||
+        !PseudoOpcodes.insert(Pseudo == nullptr ? 0 : Pseudo->ID).second) {
+      fail(Expansion.Range,
+           "MC pseudo expansions require a unique declared pseudo and result instruction");
+      return false;
+    }
+    if (!hasFlag(*Pseudo, "Pseudo") || !hasFlag(*Pseudo, "TerminalEmission") ||
+        Pseudo->Owner != "AsmPrinter" || Pseudo->Deadline != "Emission" ||
+        hasFlag(*ResultInstruction, "Pseudo") || ResultInstruction->AssemblyMnemonic.empty()) {
+      fail(Expansion.Range,
+           "MC pseudo expansions require an AsmPrinter-owned terminal pseudo and encoded result");
+      return false;
+    }
+    if (Expansion.Operands.size() != ResultInstruction->Operands.size()) {
+      fail(Expansion.Range, "MC pseudo expansion operand count must match the result instruction");
+      return false;
+    }
+
+    NormalizedMCPseudoExpansion Normalized{
+        .PseudoOpcode = Pseudo->ID,
+        .ResultOpcode = ResultInstruction->ID,
+        .Operands = {},
+    };
+    Normalized.Operands.reserve(Expansion.Operands.size());
+    for (std::size_t Index = 0; Index < Expansion.Operands.size(); ++Index) {
+      const SourceMCPseudoOperand &Operand = Expansion.Operands[Index];
+      const unsigned SourceCount = static_cast<unsigned>(Operand.SourceOperandIndex.has_value()) +
+                                   static_cast<unsigned>(!Operand.RegisterSymbol.empty()) +
+                                   static_cast<unsigned>(Operand.Immediate.has_value());
+      if (SourceCount != 1) {
+        fail(Operand.Range,
+             "MC pseudo expansion operands require exactly one operand, register, or immediate");
+        return false;
+      }
+      const NormalizedOperand &ResultOperand = ResultInstruction->Operands[Index];
+      if (Operand.SourceOperandIndex) {
+        if (*Operand.SourceOperandIndex >= Pseudo->Operands.size() ||
+            !hasCompatibleKind(Pseudo->Operands[*Operand.SourceOperandIndex], ResultOperand)) {
+          fail(Operand.Range,
+               "MC pseudo source operand must exist and match the result operand kind");
+          return false;
+        }
+        Normalized.Operands.push_back({
+            .Kind = NormalizedMCPseudoOperandKind::SourceOperand,
+            .Value = *Operand.SourceOperandIndex,
+            .Immediate = 0,
+        });
+        continue;
+      }
+      if (!Operand.RegisterSymbol.empty()) {
+        const auto Register = RegisterBySymbol.find(Operand.RegisterSymbol);
+        if (Register == RegisterBySymbol.end() ||
+            !std::ranges::contains(ResultOperand.Kinds, "Register")) {
+          fail(Operand.Range,
+               "MC pseudo fixed register must be declared and target a register operand");
+          return false;
+        }
+        Normalized.Operands.push_back({
+            .Kind = NormalizedMCPseudoOperandKind::Register,
+            .Value = Register->second,
+            .Immediate = 0,
+        });
+        continue;
+      }
+      if (!std::ranges::contains(ResultOperand.Kinds, "Immediate")) {
+        fail(Operand.Range, "MC pseudo fixed immediate must target an immediate operand");
+        return false;
+      }
+      Normalized.Operands.push_back({
+          .Kind = NormalizedMCPseudoOperandKind::Immediate,
+          .Value = 0,
+          .Immediate = *Operand.Immediate,
+      });
+    }
+    Result.MCPseudoExpansions.push_back(std::move(Normalized));
+  }
+  std::ranges::sort(Result.MCPseudoExpansions, {}, &NormalizedMCPseudoExpansion::PseudoOpcode);
+  return true;
+}
+
+} // namespace rcc::targetgen
diff --git a/backend/utils/TableGen/Common/CodeGenTarget.cpp b/backend/utils/TableGen/Common/CodeGenTarget.cpp
index 9b96d2e..d4c9795 100644
--- a/backend/utils/TableGen/Common/CodeGenTarget.cpp
+++ b/backend/utils/TableGen/Common/CodeGenTarget.cpp
@@ -37,7 +37,7 @@ CodeGenTarget::CodeGenTarget(const DescriptionAST &Input, std::string SourceName
       !normalizeSchedulingClasses(Result) || !normalizeEncodingCategories(Result) ||
       !normalizeAssemblyFormats(Result) || !normalizeInstructions(Result) ||
       !normalizeSelectionRules(Result) || !normalizeCombinerRules(Result) ||
-      !normalizeMacroFusionRules(Result)) {
+      !normalizeMacroFusionRules(Result) || !normalizeMCPseudoExpansions(Result)) {
     return std::nullopt;
   }
   std::ranges::sort(Result.RegisterUnits, {}, &SourceRegisterUnit::ID);
@@ -219,6 +219,7 @@ DescriptionGenerationResult generateDescription(const std::string &SourceName,
               .GlobalISel = emitGlobalISel(*Model, DisplayName),
               .GlobalISelCombiner = emitGlobalISelCombiner(*Model, DisplayName),
               .MacroFusion = emitMacroFusion(*Model, DisplayName),
+              .MCPseudoLowering = emitMCPseudoLowering(*Model, DisplayName),
           },
       .Diagnostics = {},
   };
diff --git a/backend/utils/TableGen/Common/CodeGenTarget.h b/backend/utils/TableGen/Common/CodeGenTarget.h
index 6d3e185..43c7383 100644
--- a/backend/utils/TableGen/Common/CodeGenTarget.h
+++ b/backend/utils/TableGen/Common/CodeGenTarget.h
@@ -151,6 +151,24 @@ struct NormalizedMacroFusionRule final {
   bool RequireSecondDestinationTie = false;
 };
 
+enum class NormalizedMCPseudoOperandKind : std::uint8_t {
+  SourceOperand,
+  Register,
+  Immediate,
+};
+
+struct NormalizedMCPseudoOperand final {
+  NormalizedMCPseudoOperandKind Kind = NormalizedMCPseudoOperandKind::SourceOperand;
+  std::uint32_t Value = 0;
+  std::int64_t Immediate = 0;
+};
+
+struct NormalizedMCPseudoExpansion final {
+  std::uint32_t PseudoOpcode = 0;
+  std::uint32_t ResultOpcode = 0;
+  std::vector<NormalizedMCPseudoOperand> Operands;
+};
+
 struct NormalizedEncodingCategory final {
   std::uint32_t ID = 0;
   std::string Symbol;
@@ -393,6 +411,7 @@ struct NormalizedTargetModel final {
   std::vector<NormalizedSelectionRule> SelectionRules;
   std::vector<NormalizedCombinerRule> CombinerRules;
   std::vector<NormalizedMacroFusionRule> MacroFusionRules;
+  std::vector<NormalizedMCPseudoExpansion> MCPseudoExpansions;
 };
 
 [[nodiscard]] std::optional<std::string_view>
@@ -437,6 +456,7 @@ private:
   [[nodiscard]] bool normalizeSelectionRules(NormalizedTargetModel &Result);
   [[nodiscard]] bool normalizeCombinerRules(NormalizedTargetModel &Result);
   [[nodiscard]] bool normalizeMacroFusionRules(NormalizedTargetModel &Result);
+  [[nodiscard]] bool normalizeMCPseudoExpansions(NormalizedTargetModel &Result);
 
   const DescriptionAST &Input;
   std::string SourceName;