[RISCV] Add generated RV64GC register description

Add an RCC-owned build-time target description generator and the initial RV64GC register model. Keep ABI aliases separate from canonical MIR register spelling.

3 files changed, 139 insertions, 0 deletions

diff --git a/backend/tools/CMakeLists.txt b/backend/tools/CMakeLists.txt
new file mode 100644
index 0000000..67d7273
--- /dev/null
+++ b/backend/tools/CMakeLists.txt
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+add_subdirectory(DescriptionGenerator)
diff --git a/backend/tools/DescriptionGenerator/CMakeLists.txt b/backend/tools/DescriptionGenerator/CMakeLists.txt
new file mode 100644
index 0000000..9bc3f26
--- /dev/null
+++ b/backend/tools/DescriptionGenerator/CMakeLists.txt
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+set(
+  RCCBackendDescriptionGeneratorCoreSources
+  "${RCC_BACKEND_SOURCE_DIR}/lib/Target/Description/TargetDescriptionGenerator.cpp"
+)
+set(
+  RCCBackendDescriptionGeneratorCoreHeaders
+  "${RCC_BACKEND_SOURCE_DIR}/lib/Target/Description/TargetDescriptionGenerator.h"
+)
+
+add_library(
+  RCCBackendDescriptionGeneratorCore
+  STATIC
+  ${RCCBackendDescriptionGeneratorCoreSources}
+)
+
+rcc_backend_configure_target(RCCBackendDescriptionGeneratorCore)
+
+target_include_directories(
+  RCCBackendDescriptionGeneratorCore
+  PUBLIC "$<BUILD_INTERFACE:${RCC_BACKEND_SOURCE_DIR}/lib/Target/Description>"
+)
+target_link_libraries(RCCBackendDescriptionGeneratorCore PUBLIC RCCBackend::Support)
+
+add_executable(RCCBackendDescriptionGenerator DescriptionGeneratorMain.cpp)
+rcc_backend_configure_target(RCCBackendDescriptionGenerator)
+target_link_libraries(RCCBackendDescriptionGenerator PRIVATE RCCBackendDescriptionGeneratorCore)
+set_target_properties(RCCBackendDescriptionGenerator PROPERTIES OUTPUT_NAME rcc-backend-descgen)
+
+rcc_backend_register_format_files(
+  "${CMAKE_CURRENT_SOURCE_DIR}/DescriptionGeneratorMain.cpp"
+  ${RCCBackendDescriptionGeneratorCoreSources}
+  ${RCCBackendDescriptionGeneratorCoreHeaders}
+)
+rcc_backend_register_tidy_files(
+  "${CMAKE_CURRENT_SOURCE_DIR}/DescriptionGeneratorMain.cpp"
+  ${RCCBackendDescriptionGeneratorCoreSources}
+)
diff --git a/backend/tools/DescriptionGenerator/DescriptionGeneratorMain.cpp b/backend/tools/DescriptionGenerator/DescriptionGeneratorMain.cpp
new file mode 100644
index 0000000..11890f6
--- /dev/null
+++ b/backend/tools/DescriptionGenerator/DescriptionGeneratorMain.cpp
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "TargetDescriptionGenerator.h"
+#include "rcc/Support/TextDiagnostic.h"
+
+#include <filesystem>
+#include <fstream>
+#include <iostream>
+#include <iterator>
+#include <string>
+#include <string_view>
+
+namespace {
+
+struct CommandLine final {
+  std::string InputPath;
+  std::string HeaderPath;
+  std::string TablesPath;
+};
+
+[[nodiscard]] bool parseCommandLine(int ArgumentCount, char *Arguments[], CommandLine &Result) {
+  for (int Index = 1; Index < ArgumentCount; ++Index) {
+    const std::string_view Argument(Arguments[Index]);
+    if (Argument == "--input" || Argument == "--header" || Argument == "--tables") {
+      if (Index + 1 >= ArgumentCount) {
+        std::cerr << "rcc-backend-descgen: missing value for " << Argument << '\n';
+        return false;
+      }
+      std::string *Destination = nullptr;
+      if (Argument == "--input")
+        Destination = &Result.InputPath;
+      else if (Argument == "--header")
+        Destination = &Result.HeaderPath;
+      else
+        Destination = &Result.TablesPath;
+      *Destination = Arguments[++Index];
+      continue;
+    }
+    std::cerr << "rcc-backend-descgen: unknown argument '" << Argument << "'\n";
+    return false;
+  }
+  if (!Result.InputPath.empty() && !Result.HeaderPath.empty() && !Result.TablesPath.empty())
+    return true;
+  std::cerr << "usage: rcc-backend-descgen --input <file> --header <file> --tables <file>\n";
+  return false;
+}
+
+[[nodiscard]] bool writeFile(const std::filesystem::path &Path, std::string_view Contents) {
+  std::error_code Error;
+  std::filesystem::create_directories(Path.parent_path(), Error);
+  if (Error) {
+    std::cerr << "rcc-backend-descgen: cannot create output directory for '" << Path.string()
+              << "': " << Error.message() << '\n';
+    return false;
+  }
+  std::ofstream Output(Path, std::ios::binary | std::ios::trunc);
+  if (!Output) {
+    std::cerr << "rcc-backend-descgen: cannot open output '" << Path.string() << "'\n";
+    return false;
+  }
+  Output.write(Contents.data(), static_cast<std::streamsize>(Contents.size()));
+  if (Output) {
+    Output.close();
+    return true;
+  }
+  std::cerr << "rcc-backend-descgen: cannot write output '" << Path.string() << "'\n";
+  return false;
+}
+
+} // namespace
+
+int main(int ArgumentCount, char *Arguments[]) {
+  CommandLine Command;
+  if (!parseCommandLine(ArgumentCount, Arguments, Command))
+    return 1;
+
+  std::ifstream Input(Command.InputPath, std::ios::binary);
+  if (!Input) {
+    std::cerr << "rcc-backend-descgen: cannot open input '" << Command.InputPath << "'\n";
+    return 1;
+  }
+  const std::string SourceText{std::istreambuf_iterator<char>(Input),
+                               std::istreambuf_iterator<char>()};
+  const rcc::targetgen::DescriptionGenerationResult Result =
+      rcc::targetgen::generateDescription(Command.InputPath, SourceText);
+  if (!Result.succeeded()) {
+    const rcc::TextSource Source(Command.InputPath, SourceText);
+    for (const rcc::TextDiagnostic &Diagnostic : Result.Diagnostics)
+      std::cerr << rcc::formatTextDiagnostic(Diagnostic, Source) << '\n';
+    return 1;
+  }
+
+  return writeFile(Command.HeaderPath, Result.Output->RegisterHeader) &&
+                 writeFile(Command.TablesPath, Result.Output->TargetTables)
+             ? 0
+             : 1;
+}