[clang-doc] Reenable time trace support (#141139)

This patch re-enables -ftime-trace support in clang-doc. Initial support
in #97644 was reverted, and never relanded. This patch adds back the
command line option, and leverages the RAII tracing infrastructure more
thoroughly.

Author: ilovepi

clang-tools-extra/clang-doc/BitcodeReader.cpp

@@ -9,6 +9,7 @@
 #include "BitcodeReader.h"
 #include "llvm/ADT/IndexedMap.h"
 #include "llvm/Support/Error.h"
+#include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/raw_ostream.h"
 #include <optional>
 
@@ -672,6 +673,7 @@ llvm::Error ClangDocBitcodeReader::readRecord(unsigned ID, T I) {
 
 template <>
 llvm::Error ClangDocBitcodeReader::readRecord(unsigned ID, Reference *I) {
+  llvm::TimeTraceScope("Reducing infos", "readRecord");
   Record R;
   llvm::StringRef Blob;
   llvm::Expected<unsigned> MaybeRecID = Stream.readRecord(ID, R, &Blob);
@@ -683,6 +685,7 @@ llvm::Error ClangDocBitcodeReader::readRecord(unsigned ID, Reference *I) {
 // Read a block of records into a single info.
 template <typename T>
 llvm::Error ClangDocBitcodeReader::readBlock(unsigned ID, T I) {
+  llvm::TimeTraceScope("Reducing infos", "readBlock");
   if (llvm::Error Err = Stream.EnterSubBlock(ID))
     return Err;
 
@@ -713,6 +716,7 @@ llvm::Error ClangDocBitcodeReader::readBlock(unsigned ID, T I) {
 
 template <typename T>
 llvm::Error ClangDocBitcodeReader::readSubBlock(unsigned ID, T I) {
+  llvm::TimeTraceScope("Reducing infos", "readSubBlock");
   switch (ID) {
   // Blocks can only have certain types of sub blocks.
   case BI_COMMENT_BLOCK_ID: {
@@ -819,6 +823,7 @@ llvm::Error ClangDocBitcodeReader::readSubBlock(unsigned ID, T I) {
 
 ClangDocBitcodeReader::Cursor
 ClangDocBitcodeReader::skipUntilRecordOrBlock(unsigned &BlockOrRecordID) {
+  llvm::TimeTraceScope("Reducing infos", "skipUntilRecordOrBlock");
   BlockOrRecordID = 0;
 
   while (!Stream.AtEndOfStream()) {
@@ -880,6 +885,7 @@ llvm::Error ClangDocBitcodeReader::validateStream() {
 }
 
 llvm::Error ClangDocBitcodeReader::readBlockInfoBlock() {
+  llvm::TimeTraceScope("Reducing infos", "readBlockInfoBlock");
   Expected<std::optional<llvm::BitstreamBlockInfo>> MaybeBlockInfo =
       Stream.ReadBlockInfoBlock();
   if (!MaybeBlockInfo)
@@ -895,6 +901,7 @@ llvm::Error ClangDocBitcodeReader::readBlockInfoBlock() {
 template <typename T>
 llvm::Expected<std::unique_ptr<Info>>
 ClangDocBitcodeReader::createInfo(unsigned ID) {
+  llvm::TimeTraceScope("Reducing infos", "createInfo");
   std::unique_ptr<Info> I = std::make_unique<T>();
   if (auto Err = readBlock(ID, static_cast<T *>(I.get())))
     return std::move(Err);
@@ -903,6 +910,7 @@ ClangDocBitcodeReader::createInfo(unsigned ID) {
 
 llvm::Expected<std::unique_ptr<Info>>
 ClangDocBitcodeReader::readBlockToInfo(unsigned ID) {
+  llvm::TimeTraceScope("Reducing infos", "readBlockToInfo");
   switch (ID) {
   case BI_NAMESPACE_BLOCK_ID:
     return createInfo<NamespaceInfo>(ID);

clang-tools-extra/clang-doc/HTMLMustacheGenerator.cpp

@@ -19,6 +19,7 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Mustache.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/TimeProfiler.h"
 
 using namespace llvm;
 using namespace llvm::json;
@@ -125,13 +126,18 @@ static Error setupTemplateFiles(const clang::doc::ClangDocContext &CDCtx) {
 Error MustacheHTMLGenerator::generateDocs(
     StringRef RootDir, StringMap<std::unique_ptr<doc::Info>> Infos,
     const clang::doc::ClangDocContext &CDCtx) {
-  if (auto Err = setupTemplateFiles(CDCtx))
-    return Err;
+  {
+    llvm::TimeTraceScope TS("Setup Templates");
+    if (auto Err = setupTemplateFiles(CDCtx))
+      return Err;
+  }
+
   // Track which directories we already tried to create.
   StringSet<> CreatedDirs;
   // Collect all output by file name and create the necessary directories.
   StringMap<std::vector<doc::Info *>> FileToInfos;
   for (const auto &Group : Infos) {
+    llvm::TimeTraceScope TS("setup directories");
     doc::Info *Info = Group.getValue().get();
 
     SmallString<128> Path;
@@ -148,15 +154,19 @@ Error MustacheHTMLGenerator::generateDocs(
     FileToInfos[Path].push_back(Info);
   }
 
-  for (const auto &Group : FileToInfos) {
-    std::error_code FileErr;
-    raw_fd_ostream InfoOS(Group.getKey(), FileErr, sys::fs::OF_None);
-    if (FileErr)
-      return createFileOpenError(Group.getKey(), FileErr);
-
-    for (const auto &Info : Group.getValue())
-      if (Error Err = generateDocForInfo(Info, InfoOS, CDCtx))
-        return Err;
+  {
+    llvm::TimeTraceScope TS("Generate Docs");
+    for (const auto &Group : FileToInfos) {
+      llvm::TimeTraceScope TS("Info to Doc");
+      std::error_code FileErr;
+      raw_fd_ostream InfoOS(Group.getKey(), FileErr, sys::fs::OF_None);
+      if (FileErr)
+        return createFileOpenError(Group.getKey(), FileErr);
+
+      for (const auto &Info : Group.getValue())
+        if (Error Err = generateDocForInfo(Info, InfoOS, CDCtx))
+          return Err;
+    }
   }
   return Error::success();
 }

clang-tools-extra/clang-doc/Mapper.cpp

@@ -7,13 +7,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "Mapper.h"
-#include "BitcodeWriter.h"
 #include "Serialize.h"
 #include "clang/AST/Comment.h"
 #include "clang/Index/USRGeneration.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSet.h"
 #include "llvm/Support/Mutex.h"
+#include "llvm/Support/TimeProfiler.h"
 
 namespace clang {
 namespace doc {
@@ -40,48 +40,66 @@ Location MapASTVisitor::getDeclLocation(const NamedDecl *D) const {
 }
 
 void MapASTVisitor::HandleTranslationUnit(ASTContext &Context) {
+  if (CDCtx.FTimeTrace)
+    llvm::timeTraceProfilerInitialize(200, "clang-doc");
   TraverseDecl(Context.getTranslationUnitDecl());
+  if (CDCtx.FTimeTrace)
+    llvm::timeTraceProfilerFinishThread();
 }
 
 template <typename T>
 bool MapASTVisitor::mapDecl(const T *D, bool IsDefinition) {
-  // If we're looking a decl not in user files, skip this decl.
-  if (D->getASTContext().getSourceManager().isInSystemHeader(D->getLocation()))
-    return true;
+  llvm::TimeTraceScope TS("Mapping declaration");
+  {
+    llvm::TimeTraceScope TS("Preamble");
+    // If we're looking a decl not in user files, skip this decl.
+    if (D->getASTContext().getSourceManager().isInSystemHeader(
+            D->getLocation()))
+      return true;
 
-  // Skip function-internal decls.
-  if (D->getParentFunctionOrMethod())
-    return true;
+    // Skip function-internal decls.
+    if (D->getParentFunctionOrMethod())
+      return true;
+  }
+
+  std::pair<std::unique_ptr<Info>, std::unique_ptr<Info>> CP;
 
-  llvm::SmallString<128> USR;
-  // If there is an error generating a USR for the decl, skip this decl.
-  if (index::generateUSRForDecl(D, USR))
-    return true;
-  // Prevent Visiting USR twice
   {
-    llvm::sys::SmartScopedLock<true> Guard(USRVisitedGuard);
-    StringRef Visited = USR.str();
-    if (USRVisited.count(Visited) && !isTypedefAnonRecord<T>(D))
+    llvm::TimeTraceScope TS("emit info from astnode");
+    llvm::SmallString<128> USR;
+    // If there is an error generating a USR for the decl, skip this decl.
+    if (index::generateUSRForDecl(D, USR))
       return true;
-    // We considered a USR to be visited only when its defined
-    if (IsDefinition)
-      USRVisited.insert(Visited);
+    // Prevent Visiting USR twice
+    {
+      llvm::sys::SmartScopedLock<true> Guard(USRVisitedGuard);
+      StringRef Visited = USR.str();
+      if (USRVisited.count(Visited) && !isTypedefAnonRecord<T>(D))
+        return true;
+      // We considered a USR to be visited only when its defined
+      if (IsDefinition)
+        USRVisited.insert(Visited);
+    }
+    bool IsFileInRootDir;
+    llvm::SmallString<128> File =
+        getFile(D, D->getASTContext(), CDCtx.SourceRoot, IsFileInRootDir);
+    CP = serialize::emitInfo(D, getComment(D, D->getASTContext()),
+                             getDeclLocation(D), CDCtx.PublicOnly);
+  }
+
+  auto &[Child, Parent] = CP;
+
+  {
+    llvm::TimeTraceScope TS("serialized info into bitcode");
+    // A null in place of a valid Info indicates that the serializer is skipping
+    // this decl for some reason (e.g. we're only reporting public decls).
+    if (Child)
+      CDCtx.ECtx->reportResult(llvm::toHex(llvm::toStringRef(Child->USR)),
+                               serialize::serialize(Child));
+    if (Parent)
+      CDCtx.ECtx->reportResult(llvm::toHex(llvm::toStringRef(Parent->USR)),
+                               serialize::serialize(Parent));
   }
-  bool IsFileInRootDir;
-  llvm::SmallString<128> File =
-      getFile(D, D->getASTContext(), CDCtx.SourceRoot, IsFileInRootDir);
-  auto [Child, Parent] =
-      serialize::emitInfo(D, getComment(D, D->getASTContext()),
-                          getDeclLocation(D), CDCtx.PublicOnly);
-
-  // A null in place of a valid Info indicates that the serializer is skipping
-  // this decl for some reason (e.g. we're only reporting public decls).
-  if (Child)
-    CDCtx.ECtx->reportResult(llvm::toHex(llvm::toStringRef(Child->USR)),
-                             serialize::serialize(Child));
-  if (Parent)
-    CDCtx.ECtx->reportResult(llvm::toHex(llvm::toStringRef(Parent->USR)),
-                             serialize::serialize(Parent));
   return true;
 }
 

clang-tools-extra/clang-doc/Representation.cpp

@@ -369,9 +369,11 @@ ClangDocContext::ClangDocContext(tooling::ExecutionContext *ECtx,
                                  StringRef OutDirectory, StringRef SourceRoot,
                                  StringRef RepositoryUrl,
                                  StringRef RepositoryLinePrefix, StringRef Base,
-                                 std::vector<std::string> UserStylesheets)
+                                 std::vector<std::string> UserStylesheets,
+                                 bool FTimeTrace)
     : ECtx(ECtx), ProjectName(ProjectName), PublicOnly(PublicOnly),
-      OutDirectory(OutDirectory), UserStylesheets(UserStylesheets), Base(Base) {
+      FTimeTrace(FTimeTrace), OutDirectory(OutDirectory),
+      UserStylesheets(UserStylesheets), Base(Base) {
   llvm::SmallString<128> SourceRootDir(SourceRoot);
   if (SourceRoot.empty())
     // If no SourceRoot was provided the current path is used as the default

clang-tools-extra/clang-doc/Representation.h

@@ -524,10 +524,13 @@ struct ClangDocContext {
   ClangDocContext(tooling::ExecutionContext *ECtx, StringRef ProjectName,
                   bool PublicOnly, StringRef OutDirectory, StringRef SourceRoot,
                   StringRef RepositoryUrl, StringRef RepositoryCodeLinePrefix,
-                  StringRef Base, std::vector<std::string> UserStylesheets);
+                  StringRef Base, std::vector<std::string> UserStylesheets,
+                  bool FTimeTrace = false);
   tooling::ExecutionContext *ECtx;
   std::string ProjectName; // Name of project clang-doc is documenting.
   bool PublicOnly; // Indicates if only public declarations are documented.
+  bool FTimeTrace; // Indicates if ftime trace is turned on
+  int Granularity; // Granularity of ftime trace
   std::string OutDirectory; // Directory for outputting generated files.
   std::string SourceRoot;   // Directory where processed files are stored. Links
                             // to definition locations will only be generated if