Remove Appveyor CI, update README (#4578)

- Remove Appveyor CI
- Write new "Getting the source" subsection, consolidating material
  from a couple of places.  Emphasize using the utils/git-sync-deps
  script for getting a known-good combination of sources.
- Built artifacts:
   - top of tree artifacts are from Kokoro CI bots
   - mention Vulkan SDK and Android NDK as alternatives

Fixes: #4577

.appveyor.yml

@@ -1,90 +0,0 @@
-# Windows Build Configuration for AppVeyor
-# http://www.appveyor.com/docs/appveyor-yml
-
-# version format
-version: "{build}"
-
-# The most recent compiler gives the most interesting new results.
-# Put it first so we get its feedback first.
-os:
-  - Visual Studio 2017
-  #- Visual Studio 2013
-
-platform:
-  - x64
-
-configuration:
-  - Debug
-  #- Release
-
-branches:
-  only:
-    - master
-
-# Travis advances the master-tot tag to current top of the tree after
-# each push into the master branch, because it relies on that tag to
-# upload build artifacts to the master-tot release. This will cause
-# double testing for each push on Appveyor: one for the push, one for
-# the tag advance. Disable testing tags.
-skip_tags: true
-
-clone_depth: 1
-
-matrix:
-  fast_finish: true # Show final status immediately if a test fails.
-  #exclude:
-  #  - os: Visual Studio 2013
-  #    configuration: Debug
-
-# scripts that run after cloning repository
-install:
-  # Install ninja
-  - set NINJA_URL="https://github.com/ninja-build/ninja/releases/download/v1.8.2/ninja-win.zip"
-  - appveyor DownloadFile %NINJA_URL% -FileName ninja.zip
-  - 7z x ninja.zip -oC:\ninja > nul
-  - set PATH=C:\ninja;C:\Python36;%PATH%
-
-before_build:
-  - git clone --depth=1 https://github.com/KhronosGroup/SPIRV-Headers.git external/spirv-headers
-  - git clone https://github.com/google/googletest.git external/googletest
-  - cd external && cd googletest && git reset --hard 1fb1bb23bb8418dc73a5a9a82bbed31dc610fec7 && cd .. && cd ..
-  - git clone --depth=1 https://github.com/google/effcee.git external/effcee
-  - git clone --depth=1 https://github.com/google/re2.git external/re2
-  # Set path and environment variables for the current Visual Studio version
-  - if "%APPVEYOR_BUILD_WORKER_IMAGE%"=="Visual Studio 2013" (call "C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" x86_amd64)
-  - if "%APPVEYOR_BUILD_WORKER_IMAGE%"=="Visual Studio 2017" (call "C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Auxiliary\Build\vcvarsall.bat" x86_amd64)
-
-build:
-  parallel: true  # enable MSBuild parallel builds
-  verbosity: minimal
-
-build_script:
-  - mkdir build && cd build
-  - cmake -GNinja -DCMAKE_BUILD_TYPE=%CONFIGURATION% -DCMAKE_INSTALL_PREFIX=install -DRE2_BUILD_TESTING=OFF ..
-  - ninja install
-
-test_script:
-  - ctest -C %CONFIGURATION% --output-on-failure --timeout 310
-
-after_test:
-  # Zip build artifacts for uploading and deploying
-  - cd install
-  - 7z a SPIRV-Tools-master-windows-"%PLATFORM%"-"%CONFIGURATION%".zip *\*
-
-artifacts:
-  - path: build\install\*.zip
-    name: artifacts-zip
-
-deploy:
-  - provider: GitHub
-    auth_token:
-      secure: TMfcScKzzFIm1YgeV/PwCRXFDCw8Xm0wY2Vb2FU6WKlbzb5eUITTpr6I5vHPnAxS
-    release: master-tot
-    description: "Continuous build of the latest master branch by Appveyor and Travis CI"
-    artifact: artifacts-zip
-    draft: false
-    prerelease: false
-    force_update: true
-    on:
-      branch: master
-      APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017

README.md

@@ -53,7 +53,7 @@ These versions undergo extra testing.
 Releases are not directly related to releases (or versions) of
 [SPIRV-Headers][spirv-headers].
 Releases of SPIRV-Tools are tested against the version of SPIRV-Headers listed
-in the DEPS file.
+in the [DEPS](DEPS) file.
 The release generally uses the most recent compatible version of SPIRV-Headers
 available at the time of release.
 No version of SPIRV-Headers other than the one listed in the DEPS file is
@@ -256,6 +256,34 @@ Contributions via merge request are welcome. Changes should:
 
 We intend to maintain a linear history on the GitHub `master` branch.
 
+### Getting the source
+
+Example of getting sources, assuming SPIRV-Tools is configured as a standalone project:
+
+    git clone https://github.com/KhronosGroup/SPIRV-Tools.git   spirv-tools
+    cd spirv-tools
+
+    # Check out sources for dependencies, at versions known to work together,
+    # as listed in the DEPS file.
+    python3 utils/git-sync-deps
+
+For some kinds of development, you may need the latest sources from the third-party projects:
+
+    git clone https://github.com/KhronosGroup/SPIRV-Headers.git spirv-tools/external/spirv-headers
+    git clone https://github.com/google/googletest.git          spirv-tools/external/googletest
+    git clone https://github.com/google/effcee.git              spirv-tools/external/effcee
+    git clone https://github.com/google/re2.git                 spirv-tools/external/re2
+
+#### Dependency on Effcee
+
+Some tests depend on the [Effcee][effcee] library for stateful matching.
+Effcee itself depends on [RE2][re2].
+
+* If SPIRV-Tools is configured as part of a larger project that already uses
+  Effcee, then that project should include Effcee before SPIRV-Tools.
+* Otherwise, SPIRV-Tools expects Effcee sources to appear in `external/effcee`
+  and RE2 sources to appear in `external/re2`.
+
 ### Source code organization
 
 * `example`: demo code of using SPIRV-Tools APIs
@@ -274,14 +302,6 @@ We intend to maintain a linear history on the GitHub `master` branch.
 * `test/`: Tests, using the [googletest][googletest] framework
 * `tools/`: Command line executables
 
-Example of getting sources, assuming SPIRV-Tools is configured as a standalone project:
-
-    git clone https://github.com/KhronosGroup/SPIRV-Tools.git   spirv-tools
-    git clone https://github.com/KhronosGroup/SPIRV-Headers.git spirv-tools/external/spirv-headers
-    git clone https://github.com/google/googletest.git          spirv-tools/external/googletest
-    git clone https://github.com/google/effcee.git              spirv-tools/external/effcee
-    git clone https://github.com/google/re2.git                 spirv-tools/external/re2
-
 ### Tests
 
 The project contains a number of tests, used to drive development
@@ -295,46 +315,12 @@ tests:
   `googletest` source into the `<spirv-dir>/external/googletest` directory before
   configuring and building the project.
 
-*Note*: You must use a version of googletest that includes
-[a fix][googletest-pull-612] for [googletest issue 610][googletest-issue-610].
-The fix is included on the googletest master branch any time after 2015-11-10.
-In particular, googletest must be newer than version 1.7.0.
-
-### Dependency on Effcee
-
-Some tests depend on the [Effcee][effcee] library for stateful matching.
-Effcee itself depends on [RE2][re2].
-
-* If SPIRV-Tools is configured as part of a larger project that already uses
-  Effcee, then that project should include Effcee before SPIRV-Tools.
-* Otherwise, SPIRV-Tools expects Effcee sources to appear in `external/effcee`
-  and RE2 sources to appear in `external/re2`.
-
-
 ## Build
 
-Instead of building manually, you can also download the binaries for your
+*Note*: Prebuilt binaries are available from the [downloads](docs/downloads.md) page.
-platform directly from the [master-tot release][master-tot-release] on GitHub.
-Those binaries are automatically uploaded by the buildbots after successful
-testing and they always reflect the current top of the tree of the master
-branch.
 
-In order to build the code, you first need to sync the external repositories
+First [get the sources](#getting-the-source).
-that it depends on. Assume that `<spirv-dir>` is the root directory of the
+Then build using CMake, Bazel, or Android ndk-build.
-checked out code:
-
-```sh
-cd <spirv-dir>
-git clone https://github.com/KhronosGroup/SPIRV-Headers.git external/spirv-headers
-git clone https://github.com/google/effcee.git external/effcee
-git clone https://github.com/google/re2.git external/re2
-git clone https://github.com/google/googletest.git external/googletest # optional
-
-```
-
-*Note*:
-The script `utils/git-sync-deps` can be used to checkout and/or update the
-contents of the repos under `external/` instead of manually maintaining them.
 
 ### Build using CMake
 You can build the project using [CMake][cmake]:
@@ -435,7 +421,7 @@ via setting `SPIRV_TOOLS_EXTRA_DEFINITIONS`. For example, by setting it to
 `/D_ITERATOR_DEBUG_LEVEL=0` on Windows, you can disable checked iterators and
 iterator debugging.
 
-### Android
+### Android ndk-build
 
 SPIR-V Tools supports building static libraries `libSPIRV-Tools.a` and
 `libSPIRV-Tools-opt.a` for Android:
@@ -456,7 +442,8 @@ $ANDROID_NDK/ndk-build -C ../android_test     \
 ```
 
 ### Updating DEPS
-Occasionally the entries in DEPS will need to be updated. This is done on demand
+
+Occasionally the entries in [DEPS](DEPS) will need to be updated. This is done on demand
 when there is a request to do this, often due to downstream breakages. There is
 a script `utils/roll_deps.sh` provided, which will generate a patch with the
 updated DEPS values. This will still need to be tested in your checkout to
@@ -743,4 +730,3 @@ limitations under the License.
 [CMake]: https://cmake.org/
 [cpp-style-guide]: https://google.github.io/styleguide/cppguide.html
 [clang-sanitizers]: http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation
-[master-tot-release]: https://github.com/KhronosGroup/SPIRV-Tools/releases/tag/master-tot

docs/downloads.md

@@ -1,14 +1,28 @@
 # Downloads
-Download the latest builds.
 
-## Release
+## Latest builds
+
+Download the latest builds of the [master](https://github.com/KhronosGroup/SPIRV-Tools/tree/master) branch.
+
+### Release build
 | Windows | Linux | MacOS |
 | --- | --- | --- |
 | [MSVC 2017](https://storage.googleapis.com/spirv-tools/badges/build_link_windows_vs2017_release.html) | [clang](https://storage.googleapis.com/spirv-tools/badges/build_link_linux_clang_release.html) | [clang](https://storage.googleapis.com/spirv-tools/badges/build_link_macos_clang_release.html) |
 | | [gcc](https://storage.googleapis.com/spirv-tools/badges/build_link_linux_gcc_release.html) | |
 
-## Debug
+### Debug build
 | Windows | Linux | MacOS |
 | --- | --- | --- |
 | [MSVC 2017](https://storage.googleapis.com/spirv-tools/badges/build_link_windows_vs2017_debug.html) | [clang](https://storage.googleapis.com/spirv-tools/badges/build_link_linux_clang_debug.html) | [clang](https://storage.googleapis.com/spirv-tools/badges/build_link_macos_clang_debug.html) |
 | | [gcc](https://storage.googleapis.com/spirv-tools/badges/build_link_linux_gcc_debug.html) | |
+
+
+## Vulkan SDK
+
+SPIRV-Tools is published as part of the [LunarG Vulkan SDK](https://www.lunarg.com/vulkan-sdk/).
+The Vulkan SDK is updated approximately every six weeks.
+
+## Android NDK
+
+SPIRV-Tools host executables, and library sources are published as
+part of the [Android NDK](https://developer.android.com/ndk/downloads).