Target Precompile Header (#124)

Initial PCH support for Target

Author: coder137

.gitignore

@@ -16,6 +16,7 @@ _deps
 .vscode/
 .vs/
 .idea/
+.cache/
 
 # Files
 *.gcov

buildcc/lib/target/cmake/mock_target.cmake

@@ -13,7 +13,6 @@ add_library(mock_target STATIC
 
     # Target friend
     src/target/friend/file_extension.cpp
-    include/target/friend/file_extension.h
 
     # Target
     src/target/target.cpp
@@ -22,10 +21,12 @@ add_library(mock_target STATIC
 
     src/target/source.cpp
     src/target/include_dir.cpp
+    src/target/pch.cpp
     src/target/lib.cpp
     src/target/flags.cpp
     src/target/additional_deps.cpp
 
+    src/target/compile_pch.cpp
     src/target/compile_source.cpp
     src/target/link_target.cpp
     src/target/build.cpp

buildcc/lib/target/cmake/target.cmake

@@ -30,12 +30,14 @@ set(TARGET_SRCS
 
     src/target/source.cpp
     src/target/include_dir.cpp
+    src/target/pch.cpp
     src/target/lib.cpp
     src/target/flags.cpp
     src/target/additional_deps.cpp
 
     src/target/recheck_states.cpp
 
+    src/target/compile_pch.cpp
     src/target/compile_source.cpp
     src/target/link_target.cpp
     src/target/build.cpp

buildcc/lib/target/include/target/target.h

@@ -61,10 +61,15 @@ class Target : public BuilderInterface {
 
     std::string target_ext{""};
     std::string obj_ext{".o"};
+    std::string pch_header_ext{".hpp"};
+    std::string pch_compile_ext{".gch"};
 
     std::string prefix_include_dir{"-I"};
     std::string prefix_lib_dir{"-L"};
 
+    std::string pch_command{"{compiler} {preprocessor_flags} {include_dirs} "
+                            "{common_compile_flags} {pch_flags} "
+                            "{compile_flags} -o {output} -c {input}"};
     std::string compile_command{
         "{compiler} {preprocessor_flags} {include_dirs} {common_compile_flags} "
         "{compile_flags} -o {output} -c {input}"};
@@ -101,7 +106,6 @@ class Target : public BuilderInterface {
   }
   virtual ~Target() {}
 
-  Target(Target &&target) = default;
   Target(const Target &target) = delete;
 
   // Builders
@@ -129,6 +133,11 @@ class Target : public BuilderInterface {
   void GlobHeaders(const fs::path &relative_to_target_path);
   void GlobHeadersAbsolute(const fs::path &absolute_path);
 
+  // PCH
+  void AddPch(const fs::path &relative_filename,
+              const fs::path &relative_to_target_path = "");
+  void AddPchAbsolute(const fs::path &absolute_filepath);
+
   // * Include and Lib directory
   void AddIncludeDir(const fs::path &relative_include_dir,
                      bool glob_headers = false);
@@ -145,6 +154,7 @@ class Target : public BuilderInterface {
   // * Flags
   void AddPreprocessorFlag(const std::string &flag);
   void AddCommonCompileFlag(const std::string &flag);
+  void AddPchFlag(const std::string &flag);
   void AddAsmCompileFlag(const std::string &flag);
   void AddCCompileFlag(const std::string &flag);
   void AddCppCompileFlag(const std::string &flag);
@@ -177,6 +187,17 @@ class Target : public BuilderInterface {
   // we can cache these variables during Target construction
   fs::path GetTargetPath() const { return ConstructTargetPath(); }
 
+  // TODO, Make these construct APIs
+  fs::path GetPchHeaderPath() const {
+    return target_intermediate_dir_ /
+           fmt::format("buildcc_pch{}", config_.pch_header_ext);
+  }
+  // Each target only has only 1 PCH file
+  fs::path GetPchCompilePath() const {
+    return GetPchHeaderPath().replace_extension(
+        fmt::format("{}{}", config_.pch_header_ext, config_.pch_compile_ext));
+  }
+
   // Const references
 
   // TODO, Shift getters to source file as well
@@ -207,6 +228,9 @@ class Target : public BuilderInterface {
   const std::unordered_set<std::string> &GetCurrentCommonCompileFlags() const {
     return current_common_compile_flags_;
   }
+  const std::unordered_set<std::string> &GetCurrentPchFlags() const {
+    return current_pch_flags_;
+  }
   const std::unordered_set<std::string> &GetCurrentAsmCompileFlags() const {
     return current_asm_compile_flags_;
   }
@@ -273,11 +297,15 @@ class Target : public BuilderInterface {
   void UnlockedAfterBuild() const;
 
   // Build
+  void BuildPch();
+  // TODO, Rename to BuildObject
   void BuildCompile(std::vector<fs::path> &source_files,
                     std::vector<fs::path> &dummy_source_files);
   void BuildLink();
 
   //
+  void PrePchCompile();
+  // TODO, Rename to PreObjectCompile
   void PreCompile();
   void PreLink();
 
@@ -298,6 +326,8 @@ class Target : public BuilderInterface {
       const std::unordered_set<std::string> &current_external_libs);
 
   // Tasks
+  void PchTask();
+  // TODO, Rename to ObjectTask and TargetTask
   void CompileTask();
   void LinkTask();
 
@@ -319,6 +349,7 @@ class Target : public BuilderInterface {
   // Construct
   fs::path ConstructObjectPath(const fs::path &absolute_source_file) const;
   fs::path ConstructTargetPath() const;
+  std::string ConstructPchCompileCommand() const;
   std::string
   ConstructCompileCommand(const fs::path &absolute_current_source) const;
   std::string ConstructLinkCommand() const;
@@ -344,12 +375,14 @@ class Target : public BuilderInterface {
   // TODO, Use an internal::Storer class / struct for this to reduce clutter
   internal::default_files current_source_files_;
   internal::default_files current_header_files_;
+  internal::default_files current_pch_files_;
   internal::default_files current_lib_deps_;
   internal::fs_unordered_set current_include_dirs_;
   internal::fs_unordered_set current_lib_dirs_;
   std::unordered_set<std::string> current_external_lib_deps_;
   std::unordered_set<std::string> current_preprocessor_flags_;
   std::unordered_set<std::string> current_common_compile_flags_;
+  std::unordered_set<std::string> current_pch_flags_;
   std::unordered_set<std::string> current_asm_compile_flags_;
   std::unordered_set<std::string> current_c_compile_flags_;
   std::unordered_set<std::string> current_cpp_compile_flags_;
@@ -360,6 +393,8 @@ class Target : public BuilderInterface {
   // Not used for serialization
   // NOTE, Always store the absolute source path -> absolute compiled source
   // path here
+  OutputInfo pch_file_;
+  // TODO, Remove current from these
   std::unordered_map<fs::path, OutputInfo, internal::PathHash>
       current_object_files_;
   OutputInfo current_target_file_;
@@ -369,6 +404,7 @@ class Target : public BuilderInterface {
   FileExt ext_{*this};
 
   tf::Taskflow tf_;
+  tf::Task pch_task_;
   tf::Task compile_task_;
   tf::Task link_task_;
 };

buildcc/lib/target/include/target/target_loader.h

@@ -47,6 +47,7 @@ class TargetLoader : public LoaderInterface {
 
   const path_unordered_set &GetLoadedSources() const { return loaded_sources_; }
   const path_unordered_set &GetLoadedHeaders() const { return loaded_headers_; }
+  const path_unordered_set &GetLoadedPchs() const { return loaded_pchs_; }
   const path_unordered_set &GetLoadedLibDeps() const {
     return loaded_lib_deps_;
   }
@@ -64,6 +65,9 @@ class TargetLoader : public LoaderInterface {
   const std::unordered_set<std::string> &GetLoadedCommonCompileFlags() const {
     return loaded_common_compile_flags_;
   }
+  const std::unordered_set<std::string> &GetLoadedPchFlags() const {
+    return loaded_pch_flags_;
+  }
   const std::unordered_set<std::string> &GetLoadedAsmCompileFlags() const {
     return loaded_asm_compile_flags_;
   }
@@ -93,6 +97,7 @@ class TargetLoader : public LoaderInterface {
 
   path_unordered_set loaded_sources_;
   path_unordered_set loaded_headers_;
+  path_unordered_set loaded_pchs_;
   path_unordered_set loaded_lib_deps_;
 
   std::unordered_set<std::string> loaded_external_lib_dirs_;
@@ -102,6 +107,7 @@ class TargetLoader : public LoaderInterface {
 
   std::unordered_set<std::string> loaded_preprocessor_flags_;
   std::unordered_set<std::string> loaded_common_compile_flags_;
+  std::unordered_set<std::string> loaded_pch_flags_;
   std::unordered_set<std::string> loaded_asm_compile_flags_;
   std::unordered_set<std::string> loaded_c_compile_flags_;
   std::unordered_set<std::string> loaded_cpp_compile_flags_;

buildcc/lib/target/mock/target/tasks.cpp

@@ -2,6 +2,8 @@
 
 namespace buildcc::base {
 
+void Target::PchTask() { BuildPch(); }
+
 void Target::CompileTask() {
   std::vector<fs::path> source_files;
   std::vector<fs::path> dummy_source_files;

buildcc/lib/target/src/target/README.md

@@ -17,6 +17,8 @@
 - [x] `include_dir.cpp`
   - Include Dir
   - Header File
+- [x] `pch.cpp`
+  - Precompile Header files 
 - [x] `lib.cpp`
   - Lib Dir
   - Lib File (full path Target supplied)
@@ -55,7 +57,7 @@
 
 ## Action on Target
 
-- [ ] `compile_header.cpp` (pch)
+- [x] `compile_header.cpp` (pch)
 - [x] `compile_source.cpp` (object)
 - [x] `link_target.cpp` (executable, library, C++20 module)
 - [x] `build.cpp`

buildcc/lib/target/src/target/build.cpp

@@ -58,19 +58,25 @@ void Target::Build() {
       {"linker", toolchain_.GetLinker()},
   });
 
+  // Load the serialized file
+  (void)loader_.Load();
+
+  // PCH Compile
+  if (!current_pch_files_.user.empty()) {
+    // TODO, Update .output at Constructor
+    pch_file_.command = ConstructPchCompileCommand();
+    PchTask();
+  }
+
   // Compile Command
+  // Link Command
   for (auto &object_rel : current_object_files_) {
     object_rel.second.command = ConstructCompileCommand(object_rel.first);
   }
+  CompileTask();
 
-  // Link Command
+  // TODO, Update .output at Constructor
   current_target_file_.command = ConstructLinkCommand();
-
-  // Load the serialized file
-  (void)loader_.Load();
-
-  // Register the tasks
-  CompileTask();
   LinkTask();
 }
 

buildcc/lib/target/src/target/compile_pch.cpp

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2021 Niket Naidu. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "target/target.h"
+
+#include "env/assert_fatal.h"
+#include "env/util.h"
+#include "target/util.h"
+
+namespace {
+
+constexpr const char *const kFormat = R"(// Generated by BuildCC
+#pragma once
+
+// clang-format off
+{aggregated_includes}
+)";
+
+void AggregateToFile(const fs::path &filename,
+                     const buildcc::internal::fs_unordered_set &header_files) {
+  std::string aggregated_includes;
+  for (const auto &hf : header_files) {
+    std::string temp = fmt::format("#include \"{}\"\r\n", hf.string());
+    aggregated_includes.append(temp);
+  }
+
+  buildcc::Command command;
+  std::string constructed_output = command.Construct(
+      kFormat, {
+                   {"aggregated_includes", aggregated_includes},
+               });
+  bool success = buildcc::env::SaveFile(filename.string().c_str(),
+                                        constructed_output, false);
+  buildcc::env::assert_fatal(success, "Could not save pch file");
+}
+
+} // namespace
+
+namespace buildcc::base {
+
+std::string Target::ConstructPchCompileCommand() const {
+  const std::string compiler = GetState().contains_cpp_src
+                                   ? GetToolchain().GetCppCompiler()
+                                   : GetToolchain().GetCCompiler();
+  const FileExt::Type file_ext_type =
+      GetState().contains_cpp_src ? FileExt::Type::Cpp : FileExt::Type::C;
+  const std::string compile_flags =
+      ext_.GetCompileFlags(file_ext_type).value_or("");
+  return command_.Construct(
+      config_.pch_command,
+      {
+          {"compiler", compiler},
+          {"pch_flags", internal::aggregate(current_pch_flags_)},
+          {"compile_flags", compile_flags},
+          {"output", GetPchCompilePath().string()},
+          {"input", GetPchHeaderPath().string()},
+      });
+}
+
+void Target::PrePchCompile() {
+  for (const auto &user_pf : current_pch_files_.user) {
+    current_pch_files_.internal.emplace(
+        buildcc::internal::Path::CreateExistingPath(user_pf));
+  }
+}
+
+void Target::BuildPch() {
+  PrePchCompile();
+  if (!loader_.IsLoaded()) {
+    dirty_ = true;
+  } else {
+    RecheckFlags(loader_.GetLoadedPreprocessorFlags(),
+                 current_preprocessor_flags_);
+    RecheckFlags(loader_.GetLoadedCommonCompileFlags(),
+                 current_common_compile_flags_);
+    RecheckFlags(loader_.GetLoadedPchFlags(), current_pch_flags_);
+    RecheckFlags(loader_.GetLoadedCCompileFlags(), current_c_compile_flags_);
+    RecheckFlags(loader_.GetLoadedCppCompileFlags(),
+                 current_cpp_compile_flags_);
+    RecheckDirs(loader_.GetLoadedIncludeDirs(), current_include_dirs_);
+    RecheckPaths(loader_.GetLoadedHeaders(), current_header_files_.internal);
+    RecheckPaths(loader_.GetLoadedPchs(), current_pch_files_.internal);
+  }
+
+  if (dirty_) {
+    AggregateToFile(GetPchHeaderPath(), current_pch_files_.user);
+    bool success = Command::Execute(pch_file_.command);
+    env::assert_fatal(success, "Failed to compile pch");
+  }
+}
+
+} // namespace buildcc::base