Merge pull request #77372 from etcwilde/ewilde/stdlib-rebuild-readme-and-sync

Extract stdlib sources for new standard library

Author: etcwilde

.gitignore

@@ -78,3 +78,17 @@ SortedCFDatabase.def
 htmlcov
 .coverage
 /benchmark/scripts/Benchmark_Driverc
+
+#==============================================================================#
+# Ignore copied Swift Stdlib files while migrating stdlib
+#==============================================================================#
+Runtimes/**/*.swift
+Runtimes/**/*.h
+Runtimes/**/*.cpp
+Runtimes/**/*.c
+Runtimes/**/*.m
+Runtimes/**/*.mm
+Runtimes/**/*.def
+Runtimes/**/*.gyb
+Runtimes/**/*.apinotes
+Runtimes/**/*.yaml

Runtimes/Readme.md

@@ -0,0 +1,99 @@
+# Swift Runtime Libraries
+
+This directory contains the pieces of the Swift runtime libraries.
+
+## Development
+
+While we're bringing up the new standard library build, please do not commit the
+standard library source files. Use the `Resync.cmake` file to copy the files as
+needed.
+
+```sh
+$ cmake -P Resync.cmake
+```
+
+> [!IMPORTANT]
+> Re-run this script after updating your Swift checkout to ensure that you are
+> building the latest standard library sources.
+
+Once the migration is completed, we will be deleting this script. It
+is a temporary workaround to avoid trying to keep multiple sets of files in
+sync.
+
+## Layering
+
+```
+╔═══════════════╗
+║               ║
+║    Testing    ║
+║               ║
+╠───────────────╣
+│               │
+│ Supplemental  │
+│               │
+├───────────────┤
+│               │
+│    Overlay    │
+│               │
+├───────────────┤
+│               │
+│     Core      │
+│               │
+└───────────────┘
+```
+
+### Core
+
+The _Core_ project contains the basic datatypes and underpinnings used by the
+rest of the libraries that make up the standard library. The _Core_ libraries
+must be built first.
+The _Core_ project provides the following libraries:
+ - `swiftCore`
+ - `swift_Concurrency`
+ - `SwiftOnoneSupport`
+ - `CommandLine`
+ - `Demangling`
+ - `Runtime`
+ - `LLVMSupport`
+ - `StdlibStubs`
+ - `Threading`
+ - `SwiftShim`
+
+These libraries must work across the platforms that Swift supports.
+
+### Overlay
+
+The Overlay project contains a few default platform overlay libraries. A
+platform overlay is responsible for exposing the system libraries into Swift in
+an ergonomic fashion. On most systems, this exposes the C standard library and a
+few other libraries that are normally available on that system. The overlay
+libraries are allowed to depend on any of the runtime libraries provided by the
+_Core_ project and libraries distributed by the platform.
+
+The platform overlay is specific to the platform that it overlays and cannot be
+used across platforms.
+
+### Supplemental
+
+The supplemental libraries provide the remainder of the standard distribution of
+libraries provided by Swift.
+
+The Supplemental libraries include:
+ - `RegexParser`
+ - `StringProcessing`
+ - `RegexBuilder`
+ - `Cxx Interop`
+ - `Synchronization`
+ - `Distributed`
+ - `Observation`
+
+The behavior of these libraries may differ slightly based on the behavior of the
+underlying operating system. These libraries are allowed to depend on the
+platform overlay and the libraries provided by the _Core_ project.
+
+### Testing
+
+The testing project provides testing support for the libraries that make up the
+standard library. These libraries are optional and are not intended for
+shipping. They must be built last, after the Core, the Overlay, and the
+Supplemental libraries.

Runtimes/Resync.cmake

@@ -0,0 +1,70 @@
+# This CMake script keeps the files in the new standard library build in sync
+# with the existing standard library.
+
+# TODO: Once the migration is completed, we can delete this file
+
+cmake_minimum_required(VERSION 3.21)
+
+# Where the standard library lives today
+set(StdlibSources "${CMAKE_CURRENT_LIST_DIR}/../stdlib")
+
+message(STATUS "Source dir: ${StdlibSources}")
+
+# Copy the files under the "name" directory in the standard library into the new
+# location under Runtimes
+function(copy_library_sources name from_prefix to_prefix)
+  message(STATUS "${name}[${StdlibSources}/${from_prefix}/${name}] -> ${to_prefix}/${name} ")
+
+  file(GLOB_RECURSE filenames
+    FOLLOW_SYMLINKS
+    LIST_DIRECTORIES FALSE
+    RELATIVE "${StdlibSources}/${from_prefix}"
+    "${StdlibSources}/${from_prefix}/${name}/*.swift"
+    "${StdlibSources}/${from_prefix}/${name}/*.h"
+    "${StdlibSources}/${from_prefix}/${name}/*.cpp"
+    "${StdlibSources}/${from_prefix}/${name}/*.c"
+    "${StdlibSources}/${from_prefix}/${name}/*.mm"
+    "${StdlibSources}/${from_prefix}/${name}/*.m"
+    "${StdlibSources}/${from_prefix}/${name}/*.def"
+    "${StdlibSources}/${from_prefix}/${name}/*.gyb"
+    "${StdlibSources}/${from_prefix}/${name}/*.apinotes"
+    "${StdlibSources}/${from_prefix}/${name}/*.yaml")
+
+  foreach(file ${filenames})
+    # Get and create the directory
+    get_filename_component(dirname ${file} DIRECTORY)
+    file(MAKE_DIRECTORY "${to_prefix}/${dirname}")
+    file(COPY_FILE
+      "${StdlibSources}/${from_prefix}/${file}"         # From
+      "${CMAKE_CURRENT_LIST_DIR}/${to_prefix}/${file}"  # To
+      RESULT _output
+      ONLY_IF_DIFFERENT)
+    if(_output)
+      message(SEND_ERROR
+        "Copy ${from_prefix}/${file} -> ${to_prefix}/${file} Failed: ${_output}")
+    endif()
+  endforeach()
+endfunction()
+
+# Directories in the existing standard library that make up the Core project
+
+# Copy shared core headers
+copy_library_sources(include "" "Core")
+
+set(CoreLibs
+  LLVMSupport)
+
+  # Add these as we get them building
+  # core
+  # Concurrency
+  # SwiftOnoneSUpport
+  # CommandLineSupport
+  # Demangling
+  # runtime)
+
+foreach(library ${CoreLibs})
+  copy_library_sources(${library} "public" "Core")
+endforeach()
+
+# TODO: Add source directories for the platform overlays, supplemental
+# libraries, and test support libraries.