1 files changed, 180 insertions, 0 deletions
diff --git a/contrib/llvm-project/clang/lib/Frontend/HeaderIncludeGen.cpp b/contrib/llvm-project/clang/lib/Frontend/HeaderIncludeGen.cpp
new file mode 100644
index 000000000000..5f91157816b0
--- /dev/null
+++ b/contrib/llvm-project/clang/lib/Frontend/HeaderIncludeGen.cpp
@@ -0,0 +1,180 @@
+//===-- HeaderIncludeGen.cpp - Generate Header Includes -------------------===//
+//
+// 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 "clang/Frontend/DependencyOutputOptions.h"
+#include "clang/Frontend/Utils.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Frontend/FrontendDiagnostic.h"
+#include "clang/Lex/Preprocessor.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace clang;
+
+namespace {
+class HeaderIncludesCallback : public PPCallbacks {
+  SourceManager &SM;
+  raw_ostream *OutputFile;
+  const DependencyOutputOptions &DepOpts;
+  unsigned CurrentIncludeDepth;
+  bool HasProcessedPredefines;
+  bool OwnsOutputFile;
+  bool ShowAllHeaders;
+  bool ShowDepth;
+  bool MSStyle;
+
+public:
+  HeaderIncludesCallback(const Preprocessor *PP, bool ShowAllHeaders_,
+                         raw_ostream *OutputFile_,
+                         const DependencyOutputOptions &DepOpts,
+                         bool OwnsOutputFile_, bool ShowDepth_, bool MSStyle_)
+      : SM(PP->getSourceManager()), OutputFile(OutputFile_), DepOpts(DepOpts),
+        CurrentIncludeDepth(0), HasProcessedPredefines(false),
+        OwnsOutputFile(OwnsOutputFile_), ShowAllHeaders(ShowAllHeaders_),
+        ShowDepth(ShowDepth_), MSStyle(MSStyle_) {}
+
+  ~HeaderIncludesCallback() override {
+    if (OwnsOutputFile)
+      delete OutputFile;
+  }
+
+  void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                   SrcMgr::CharacteristicKind FileType,
+                   FileID PrevFID) override;
+};
+}
+
+static void PrintHeaderInfo(raw_ostream *OutputFile, StringRef Filename,
+                            bool ShowDepth, unsigned CurrentIncludeDepth,
+                            bool MSStyle) {
+  // Write to a temporary string to avoid unnecessary flushing on errs().
+  SmallString<512> Pathname(Filename);
+  if (!MSStyle)
+    Lexer::Stringify(Pathname);
+
+  SmallString<256> Msg;
+  if (MSStyle)
+    Msg += "Note: including file:";
+
+  if (ShowDepth) {
+    // The main source file is at depth 1, so skip one dot.
+    for (unsigned i = 1; i != CurrentIncludeDepth; ++i)
+      Msg += MSStyle ? ' ' : '.';
+
+    if (!MSStyle)
+      Msg += ' ';
+  }
+  Msg += Pathname;
+  Msg += '\n';
+
+  *OutputFile << Msg;
+  OutputFile->flush();
+}
+
+void clang::AttachHeaderIncludeGen(Preprocessor &PP,
+                                   const DependencyOutputOptions &DepOpts,
+                                   bool ShowAllHeaders, StringRef OutputPath,
+                                   bool ShowDepth, bool MSStyle) {
+  raw_ostream *OutputFile = &llvm::errs();
+  bool OwnsOutputFile = false;
+
+  // Choose output stream, when printing in cl.exe /showIncludes style.
+  if (MSStyle) {
+    switch (DepOpts.ShowIncludesDest) {
+    default:
+      llvm_unreachable("Invalid destination for /showIncludes output!");
+    case ShowIncludesDestination::Stderr:
+      OutputFile = &llvm::errs();
+      break;
+    case ShowIncludesDestination::Stdout:
+      OutputFile = &llvm::outs();
+      break;
+    }
+  }
+
+  // Open the output file, if used.
+  if (!OutputPath.empty()) {
+    std::error_code EC;
+    llvm::raw_fd_ostream *OS = new llvm::raw_fd_ostream(
+        OutputPath.str(), EC,
+        llvm::sys::fs::OF_Append | llvm::sys::fs::OF_Text);
+    if (EC) {
+      PP.getDiagnostics().Report(clang::diag::warn_fe_cc_print_header_failure)
+          << EC.message();
+      delete OS;
+    } else {
+      OS->SetUnbuffered();
+      OutputFile = OS;
+      OwnsOutputFile = true;
+    }
+  }
+
+  // Print header info for extra headers, pretending they were discovered by
+  // the regular preprocessor. The primary use case is to support proper
+  // generation of Make / Ninja file dependencies for implicit includes, such
+  // as sanitizer blacklists. It's only important for cl.exe compatibility,
+  // the GNU way to generate rules is -M / -MM / -MD / -MMD.
+  for (const auto &Header : DepOpts.ExtraDeps)
+    PrintHeaderInfo(OutputFile, Header, ShowDepth, 2, MSStyle);
+  PP.addPPCallbacks(std::make_unique<HeaderIncludesCallback>(
+      &PP, ShowAllHeaders, OutputFile, DepOpts, OwnsOutputFile, ShowDepth,
+      MSStyle));
+}
+
+void HeaderIncludesCallback::FileChanged(SourceLocation Loc,
+                                         FileChangeReason Reason,
+                                       SrcMgr::CharacteristicKind NewFileType,
+                                       FileID PrevFID) {
+  // Unless we are exiting a #include, make sure to skip ahead to the line the
+  // #include directive was at.
+  PresumedLoc UserLoc = SM.getPresumedLoc(Loc);
+  if (UserLoc.isInvalid())
+    return;
+
+  // Adjust the current include depth.
+  if (Reason == PPCallbacks::EnterFile) {
+    ++CurrentIncludeDepth;
+  } else if (Reason == PPCallbacks::ExitFile) {
+    if (CurrentIncludeDepth)
+      --CurrentIncludeDepth;
+
+    // We track when we are done with the predefines by watching for the first
+    // place where we drop back to a nesting depth of 1.
+    if (CurrentIncludeDepth == 1 && !HasProcessedPredefines) {
+      if (!DepOpts.ShowIncludesPretendHeader.empty()) {
+        PrintHeaderInfo(OutputFile, DepOpts.ShowIncludesPretendHeader,
+                        ShowDepth, 2, MSStyle);
+      }
+      HasProcessedPredefines = true;
+    }
+
+    return;
+  } else
+    return;
+
+  // Show the header if we are (a) past the predefines, or (b) showing all
+  // headers and in the predefines at a depth past the initial file and command
+  // line buffers.
+  bool ShowHeader = (HasProcessedPredefines ||
+                     (ShowAllHeaders && CurrentIncludeDepth > 2));
+  unsigned IncludeDepth = CurrentIncludeDepth;
+  if (!HasProcessedPredefines)
+    --IncludeDepth; // Ignore indent from <built-in>.
+  else if (!DepOpts.ShowIncludesPretendHeader.empty())
+    ++IncludeDepth; // Pretend inclusion by ShowIncludesPretendHeader.
+
+  // Dump the header include information we are past the predefines buffer or
+  // are showing all headers and this isn't the magic implicit <command line>
+  // header.
+  // FIXME: Identify headers in a more robust way than comparing their name to
+  // "<command line>" and "<built-in>" in a bunch of places.
+  if (ShowHeader && Reason == PPCallbacks::EnterFile &&
+      UserLoc.getFilename() != StringRef("<command line>")) {
+    PrintHeaderInfo(OutputFile, UserLoc.getFilename(), ShowDepth, IncludeDepth,
+                    MSStyle);
+  }
+}