Alter project so builds fail faster

[fosterbrereton]

Right now the Clang dependencies are built before the hyde sources are. If there is an error in the hyde sources (especially building on Linux) the build takes more than two hours before those errors are discovered.

It would be great to build only the minimal number of Clang dependencies first to get the hyde sources built, then build the rest of Clang. That way if there are any failures in the hyde sources, they will be discovered sooner, saving us time.

Here are some initial attempts to alter CMakeLists.txt (the error message it produces will follow):

# Copyright 2018 Adobe
# All Rights Reserved.

# NOTICE: Adobe permits you to use, modify, and distribute this file in
# accordance with the terms of the Adobe license agreement accompanying
# it. If you have received this file from a source other than Adobe,
# then your use, modification, or distribution of it requires the prior
# written permission of Adobe.

cmake_minimum_required(VERSION 3.23)

set(CMAKE_POLICY_DEFAULT_CMP0077 NEW) # Avoid overriding normal variables with option()
set(CMAKE_POLICY_DEFAULT_CMP0126 NEW) # Avoid overriding normal variables with set(CACHE)

include(FetchContent)

set(FETCHCONTENT_QUIET FALSE)

set(CMAKE_OSX_ARCHITECTURES "x86_64;arm64")

project(hyde)

set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_EXTENSIONS OFF)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_XCODE_GENERATE_SCHEME OFF)

message(STATUS "INFO: Setting up LLVM...")

FetchContent_Declare(
    llvm
    GIT_REPOSITORY https://github.com/llvm/llvm-project.git
    GIT_TAG 8dfdcc7b7bf66834a761bd8de445840ef68e4d1a # llvmorg-15.0.7
    GIT_SHALLOW TRUE
    GIT_PROGRESS TRUE
    SOURCE_SUBDIR llvm
)

set(LLVM_ENABLE_PROJECTS "clang")
set(LLVM_TARGETS_TO_BUILD "X86;AArch64")
set(LLVM_ENABLE_ZSTD OFF)

FetchContent_MakeAvailable(llvm)

message(STATUS "INFO: LLVM source dir: ${llvm_SOURCE_DIR}")
message(STATUS "INFO: LLVM binary dir: ${llvm_BINARY_DIR}")

set(SRC_SOURCES
    ${PROJECT_SOURCE_DIR}/sources/autodetect.cpp
    ${PROJECT_SOURCE_DIR}/sources/main.cpp
    ${PROJECT_SOURCE_DIR}/sources/output_yaml.cpp
)

set(SRC_EMITTERS
    ${PROJECT_SOURCE_DIR}/emitters/yaml_base_emitter.cpp
    ${PROJECT_SOURCE_DIR}/emitters/yaml_class_emitter.cpp
    ${PROJECT_SOURCE_DIR}/emitters/yaml_enum_emitter.cpp
    ${PROJECT_SOURCE_DIR}/emitters/yaml_function_emitter.cpp
    ${PROJECT_SOURCE_DIR}/emitters/yaml_library_emitter.cpp
    ${PROJECT_SOURCE_DIR}/emitters/yaml_sourcefile_emitter.cpp
)

set(SRC_MATCHERS
    ${PROJECT_SOURCE_DIR}/matchers/class_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/enum_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/function_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/namespace_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/typealias_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/typedef_matcher.cpp
    ${PROJECT_SOURCE_DIR}/matchers/utilities.cpp
)

set(SRC_YAMLCPP
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/binary.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/convert.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/depthguard.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/directives.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/emit.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/emitfromevents.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/emitter.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/emitterstate.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/emitterutils.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/exceptions.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/exp.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/memory.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/node.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/node_data.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/nodebuilder.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/nodeevents.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/null.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/ostream_wrapper.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/parse.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/parser.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/regex_yaml.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/scanner.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/scanscalar.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/scantag.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/scantoken.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/simplekey.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/singledocparser.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/stream.cpp
    ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/src/tag.cpp
)

# We make the hyde sources a library so that we can define these sources as a dependency of the
# executable. This will cause cmake to order the compilation of these files ahead of any other
# dependencies like Clang (because we specify this library as the first dependency of the
# executable.) The big benefit to this change is that they'll get compiled (and possibly
# break) _first_, letting builds fail faster than if Clang we're compiled ahead of these sources.

add_library(hyde_lib STATIC)

target_sources(hyde_lib
    PRIVATE
        ${SRC_SOURCES}
        ${SRC_EMITTERS}
        ${SRC_MATCHERS}
        ${SRC_YAMLCPP}
)

source_group(sources FILES ${SRC_SOURCES})
source_group(emitters FILES ${SRC_EMITTERS})
source_group(matchers FILES ${SRC_MATCHERS})
source_group(yaml-cpp FILES ${SRC_YAMLCPP})

target_include_directories(hyde_lib
    PUBLIC
        ${CMAKE_CURRENT_SOURCE_DIR}
        ${CMAKE_CURRENT_SOURCE_DIR}/include
        ${PROJECT_SOURCE_DIR}/submodules/yaml-cpp/include/
        ${PROJECT_SOURCE_DIR}/submodules/json/include/
        ${llvm_SOURCE_DIR}/clang/include
        ${llvm_BINARY_DIR}/tools/clang/include
        ${llvm_SOURCE_DIR}/llvm/include
        ${llvm_BINARY_DIR}/include
)

target_compile_options(hyde_lib
    PUBLIC
        -Wall
        -Wno-comment
        -Werror
        -Wno-range-loop-analysis
)

if (NOT LLVM_ENABLE_RTTI)
    target_compile_options(hyde_lib PRIVATE -fno-rtti)
endif()

# cmake won't let you make an executable with no source files, so we create a dummy empty file.
# See: https://stackoverflow.com/a/34234515/153535
file(WRITE ${CMAKE_CURRENT_BINARY_DIR}/null.cpp "// See CMakeLists.txt for the origin of this file.")
add_executable(hyde ${CMAKE_CURRENT_BINARY_DIR}/null.cpp)

target_link_libraries(hyde
    hyde_lib
    clang
    clangAST
    clangASTMatchers
    clangBasic
    clangFrontend
    clangLex
    clangTooling
)

if (PROJECT_IS_TOP_LEVEL)
    set_target_properties(hyde PROPERTIES XCODE_GENERATE_SCHEME ON)
endif()

Here is the error message produced by the build system:

[1/3639] Building CXX object CMakeFiles/hyde_lib.dir/sources/main.cpp.o
FAILED: CMakeFiles/hyde_lib.dir/sources/main.cpp.o 
/usr/bin/c++  -I/home/runner/work/hyde/hyde -I/home/runner/work/hyde/hyde/include -I/home/runner/work/hyde/hyde/submodules/yaml-cpp/include -I/home/runner/work/hyde/hyde/submodules/json/include -I/home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include -I/home/runner/work/hyde/hyde/build/_deps/llvm-build/tools/clang/include -I/home/runner/work/hyde/hyde/build/_deps/llvm-src/llvm/include -I/home/runner/work/hyde/hyde/build/_deps/llvm-build/include -O3 -DNDEBUG -std=c++20 -Wall -Wno-comment -Werror -Wno-range-loop-analysis -fno-rtti -MD -MT CMakeFiles/hyde_lib.dir/sources/main.cpp.o -MF CMakeFiles/hyde_lib.dir/sources/main.cpp.o.d -o CMakeFiles/hyde_lib.dir/sources/main.cpp.o -c /home/runner/work/hyde/hyde/sources/main.cpp
In file included from /home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include/clang/AST/ASTContext.h:18,
                 from /home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include/clang/Frontend/ASTUnit.h:17,
                 from /home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include/clang/Frontend/FrontendAction.h:23,
                 from /home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include/clang/Frontend/FrontendActions.h:12,
                 from /home/runner/work/hyde/hyde/sources/main.cpp:23:
/home/runner/work/hyde/hyde/build/_deps/llvm-src/clang/include/clang/AST/ASTFwd.h:21:10: fatal error: clang/AST/DeclNodes.inc: No such file or directory
   21 | #include "clang/AST/DeclNodes.inc"
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
[2/3[6](https://github.com/adobe/hyde/actions/runs/5613466345/job/15209547361#step:4:7)3[9](https://github.com/adobe/hyde/actions/runs/5613466345/job/15209547361#step:4:10)] Building CXX object CMakeFiles/hyde_lib.dir/sources/autodetect.cpp.o
[3/3639] Building CXX object CMakeFiles/hyde_lib.dir/sources/output_yaml.cpp.o
ninja: build stopped: subcommand failed.
Error: Process completed with exit code 1.

It would seem no reordering of dependencies in target_link_libraries causes the Clang dependencies to build before the hyde_lib dependencies. I suspect the clangAST and/or clangASTMatchers dependency is responsible for constructing clang/AST/DeclNodes.inc which the rest of the Clang headers depend on.