1 files changed, 119 insertions, 0 deletions
diff --git a/libc/utils/HdrGen/Generator.cpp b/libc/utils/HdrGen/Generator.cpp
new file mode 100644
index 00000000000..996f3bf2699
--- /dev/null
+++ b/libc/utils/HdrGen/Generator.cpp
@@ -0,0 +1,119 @@
+//===---- Implementation of the main header generation class -----*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "Generator.h"
+
+#include "IncludeFileCommand.h"
+#include "PublicAPICommand.h"
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cstdlib>
+#include <memory>
+
+static const char CommandPrefix[] = "%%";
+static const size_t CommandPrefixSize = llvm::StringRef(CommandPrefix).size();
+
+static const char CommentPrefix[] = "<!>";
+
+static const char ParamNamePrefix[] = "${";
+static const size_t ParamNamePrefixSize =
+    llvm::StringRef(ParamNamePrefix).size();
+static const char ParamNameSuffix[] = "}";
+static const size_t ParamNameSuffixSize =
+    llvm::StringRef(ParamNameSuffix).size();
+
+namespace llvm_libc {
+
+Command *Generator::getCommandHandler(llvm::StringRef CommandName) {
+  if (CommandName == IncludeFileCommand::Name) {
+    if (!IncludeFileCmd)
+      IncludeFileCmd = std::make_unique<IncludeFileCommand>();
+    return IncludeFileCmd.get();
+  } else if (CommandName == PublicAPICommand::Name) {
+    if (!PublicAPICmd)
+      PublicAPICmd = std::make_unique<PublicAPICommand>();
+    return PublicAPICmd.get();
+  } else {
+    return nullptr;
+  }
+}
+
+void Generator::parseCommandArgs(llvm::StringRef ArgStr, ArgVector &Args) {
+  if (!ArgStr.contains(',') && ArgStr.trim(' ').trim('\t').size() == 0) {
+    // If it is just space between the parenthesis
+    return;
+  }
+
+  ArgStr.split(Args, ",");
+  for (llvm::StringRef &A : Args) {
+    A = A.trim(' ');
+    if (A.startswith(ParamNamePrefix) && A.endswith(ParamNameSuffix)) {
+      A = A.drop_front(ParamNamePrefixSize).drop_back(ParamNameSuffixSize);
+      A = ArgMap[A];
+    }
+  }
+}
+
+void Generator::generate(llvm::raw_ostream &OS, llvm::RecordKeeper &Records) {
+  auto DefFileBuffer = llvm::MemoryBuffer::getFile(HeaderDefFile);
+  if (!DefFileBuffer) {
+    llvm::errs() << "Unable to open " << HeaderDefFile << ".\n";
+    std::exit(1);
+  }
+  llvm::SourceMgr SrcMgr;
+  unsigned DefFileID = SrcMgr.AddNewSourceBuffer(
+      std::move(DefFileBuffer.get()), llvm::SMLoc::getFromPointer(nullptr));
+
+  llvm::StringRef Content = SrcMgr.getMemoryBuffer(DefFileID)->getBuffer();
+  while (true) {
+    std::pair<llvm::StringRef, llvm::StringRef> P = Content.split('\n');
+    Content = P.second;
+
+    llvm::StringRef Line = P.first.trim(' ');
+    if (Line.startswith(CommandPrefix)) {
+      Line = Line.drop_front(CommandPrefixSize);
+
+      P = Line.split("(");
+      if (P.second.empty() || P.second[P.second.size() - 1] != ')') {
+        SrcMgr.PrintMessage(llvm::SMLoc::getFromPointer(P.second.data()),
+                            llvm::SourceMgr::DK_Error,
+                            "Command argument list should begin with '(' "
+                            "and end with ')'.");
+        std::exit(1);
+      }
+      llvm::StringRef CommandName = P.first;
+      Command *Cmd = getCommandHandler(CommandName);
+      if (Cmd == nullptr) {
+        SrcMgr.PrintMessage(llvm::SMLoc::getFromPointer(CommandName.data()),
+                            llvm::SourceMgr::DK_Error,
+                            "Unknown command '%%" + CommandName + "'.");
+        std::exit(1);
+      }
+
+      llvm::StringRef ArgStr = P.second.drop_back(1);
+      ArgVector Args;
+      parseCommandArgs(ArgStr, Args);
+
+      Command::ErrorReporter Reporter(
+          llvm::SMLoc::getFromPointer(CommandName.data()), SrcMgr);
+      Cmd->run(OS, Args, StdHeader, Records, Reporter);
+    } else if (!Line.startswith(CommentPrefix)) {
+      // There is no comment or command on this line so we just write it as is.
+      OS << P.first << "\n";
+    }
+
+    if (P.second.empty())
+      break;
+  }
+}
+
+} // namespace llvm_libc