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Generate build information from CHANGES.md

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This PR significantly reworks the way glslang is versioned.

Instead of committing changes to the `GLSLANG_MINOR_VERSION` define in
`glslang/Public/ShaderLang.h`, and using `make-revision` to generate
`GLSLANG_PATCH_LEVEL` in `glslang/Include/revision.h`, all version
information is now derived from the new `CHANGES.md` file.

`CHANGES.md` acts as the single source of truth for glslang version
information, along with a convenient place to put all release notes for
each notable change made.

`CHANGES.md` is parsed using the new `build_info.py` python script.
This script can read basic template files to produce new source files,
which it does to read the new `build_info.h.tmpl` to generate (at build
time) a glslang private header at
`<build-dir>/include/glslang/build_info.h`.
I've written generators for each of the CMake, Bazel, gn, and
`Android.mk` build scripts.

The new version code conforms to the Semantic Versioning 2.0 spec.

This new version is also used by the CMake rules to produce versioned
shared objects, including a major-versioned SONAME.

New APIs:
---------

* `glslang::GetVersion()` returns a `Version` struct with the version
  major, minor, patch and flavor.

Breaking API changes:
---------------------

* The public defines `GLSLANG_MINOR_VERSION` and `GLSLANG_PATCH_LEVEL`
  have been entirely removed.
* `glslang/Public/ShaderLang.h` and `glslang/Include/revision.h` have
  been deleted.
* Instead, `<build-dir>/include/glslang/build_info.h` is created in
  the build directory, and `<build-dir>/include` is a CMake `PUBLIC`
  (dependee-inherited) include directory for the glslang targets.
* `<build-dir>/include/glslang/build_info.h` contains the following
   new #defines:
   `GLSLANG_VERSION_MAJOR`, `GLSLANG_VERSION_MINOR`,
   `GLSLANG_VERSION_PATCH`, `GLSLANG_VERSION_FLAVOR`,
   `GLSLANG_VERSION_GREATER_THAN(major, minor, patch)`,
   `GLSLANG_VERSION_GREATER_OR_EQUAL_TO(major, minor, patch)`,
   `GLSLANG_VERSION_LESS_THAN(major, minor, patch)`,
   `GLSLANG_VERSION_LESS_OR_EQUAL_TO(major, minor, patch)`
*  The CMake install output directory contains a copy of
   `build_info.h` at: `include/glslang/build_info.h`
*  Python3 is now always required to build glslang (likely always
   required for transitive dependency builds).
This commit is contained in:
Ben Clayton
2020-06-17 11:17:19 +01:00
parent 5aaa0c2bc8
commit fbe9a23baf
16 changed files with 514 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
CMakeLists.txt
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@@ -57,6 +57,14 @@ if(BUILD_SHARED_LIBS)
set(LIB_TYPE SHARED)
endif()
if ("${CMAKE_BUILD_TYPE}" STREQUAL "")
# This logic inside SPIRV-Tools, which can upset build target dependencies
# if changed after targets are already defined. To prevent these issues,
# ensure CMAKE_BUILD_TYPE is assigned early and at the glslang root scope.
message(STATUS "No build type selected, default to Debug")
set(CMAKE_BUILD_TYPE "Debug")
endif()
option(SKIP_GLSLANG_INSTALL "Skip installation" ${SKIP_GLSLANG_INSTALL})
if(NOT ${SKIP_GLSLANG_INSTALL})
set(ENABLE_GLSLANG_INSTALL ON)
@@ -221,12 +229,54 @@ endfunction(glslang_set_link_args)
# CMake needs to find the right version of python, right from the beginning,
# otherwise, it will find the wrong version and fail later
if(BUILD_EXTERNAL AND IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/External)
find_package(PythonInterp 3 REQUIRED)
find_package(PythonInterp 3 REQUIRED)
# We depend on these for later projects, so they should come first.
add_subdirectory(External)
endif()
# Root directory for build-time generated include files
set(GLSLANG_GENERATED_INCLUDEDIR "${CMAKE_BINARY_DIR}/include")
################################################################################
# Build version information generation
################################################################################
set(GLSLANG_CHANGES_FILE "${CMAKE_SOURCE_DIR}/CHANGES.md")
set(GLSLANG_BUILD_INFO_PY "${CMAKE_SOURCE_DIR}/build_info.py")
set(GLSLANG_BUILD_INFO_H_TMPL "${CMAKE_SOURCE_DIR}/build_info.h.tmpl")
set(GLSLANG_BUILD_INFO_H "${GLSLANG_GENERATED_INCLUDEDIR}/glslang/build_info.h")
# Command to build the build_info.h file
add_custom_command(
OUTPUT ${GLSLANG_BUILD_INFO_H}
COMMAND ${PYTHON_EXECUTABLE} "${GLSLANG_BUILD_INFO_PY}"
${CMAKE_CURRENT_SOURCE_DIR}
"-i" ${GLSLANG_BUILD_INFO_H_TMPL}
"-o" ${GLSLANG_BUILD_INFO_H}
DEPENDS ${GLSLANG_BUILD_INFO_PY}
${GLSLANG_CHANGES_FILE}
${GLSLANG_BUILD_INFO_H_TMPL}
COMMENT "Generating ${GLSLANG_BUILD_INFO_H}")
# Target to build the build_info.h file
add_custom_target(glslang-build-info DEPENDS ${GLSLANG_BUILD_INFO_H})
# Populate the CMake GLSLANG_VERSION* variables with the build version
# information.
execute_process(
COMMAND ${PYTHON_EXECUTABLE} "${GLSLANG_BUILD_INFO_PY}"
${CMAKE_CURRENT_SOURCE_DIR} "<major>.<minor>.<patch><-flavor>;<major>;<minor>;<patch>;<flavor>"
OUTPUT_VARIABLE "GLSLANG_VERSIONS"
OUTPUT_STRIP_TRAILING_WHITESPACE)
list(GET "GLSLANG_VERSIONS" 0 "GLSLANG_VERSION")
list(GET "GLSLANG_VERSIONS" 1 "GLSLANG_VERSION_MAJOR")
list(GET "GLSLANG_VERSIONS" 2 "GLSLANG_VERSION_MINOR")
list(GET "GLSLANG_VERSIONS" 3 "GLSLANG_VERSION_PATCH")
list(GET "GLSLANG_VERSIONS" 4 "GLSLANG_VERSION_FLAVOR")
configure_file(${GLSLANG_CHANGES_FILE} "${CMAKE_CURRENT_BINARY_DIR}/CHANGES.md") # Required to re-run cmake on version change
# glslang_add_build_info_dependency() adds the glslang-build-info dependency and
# generated include directories to target.
function(glslang_add_build_info_dependency target)
target_include_directories(${target} PUBLIC $<BUILD_INTERFACE:${GLSLANG_GENERATED_INCLUDEDIR}>)
add_dependencies(${target} glslang-build-info)
endfunction()
# glslang_only_export_explicit_symbols() makes the symbol visibility hidden by
# default for <target> when building shared libraries, and sets the
@@ -256,6 +306,11 @@ else()
message(NOTICE "Your CMake version is ${CMAKE_VERSION}. Update to at least 3.16 to enable precompiled headers to speed up incremental builds")
endif()
if(BUILD_EXTERNAL AND IS_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/External)
# We depend on these for later projects, so they should come first.
add_subdirectory(External)
endif()
if(NOT TARGET SPIRV-Tools-opt)
set(ENABLE_OPT OFF)
endif()