ASDAlexander77 · Oct 6, 2026 · Oct 6, 2026
diff --git a/.github/workflows/create-release.yml b/.github/workflows/create-release.yml
@@ -240,7 +240,7 @@ jobs:
         continue-on-error: false
         working-directory: ${{github.workspace}}/__build/tslang/msbuild/x64/release
         env:
-          TSLANG_ANDROID_DEFAULT_LIB_PATH: ${{github.workspace}}/TypeScriptCompilerDefaultLib/__build/android/x86_64
+          TSLANG_ANDROID_DEFAULT_LIB_PATH: ${{github.workspace}}/TypeScriptCompilerDefaultLib/__build
         run: |
           $out = ctest -C ${{ env.BUILD_TYPE }} -R "test-compile-android-" --output-on-failure 2>&1 | Out-String
           $out
@@ -251,28 +251,24 @@ jobs:
       - name: Create Zip of Windows Asset
         working-directory: ${{github.workspace}}/__build
         # Flatten the compiler/runtime binaries into the archive root, and add the
-        # default library as a whole tree so its per-build, per-memory-model subfolders
-        # are preserved:
-        #   defaultlib/{dll,lib}/{debug,release}/{gc,rc,none},
-        #   defaultlib/*.d.ts, defaultlib/generics/
+        # default library as a whole tree so its per-target, per-build, per-memory-model
+        # subfolders are preserved, Android's among them (tslang --print-default-lib-dir names one):
+        #   defaultlib/{dll,lib}/<arch>/<vendor>/<os>/<env>/{debug,release}/{gc,rc,none},
+        #   defaultlib/*.d.ts, defaultlib/generics/ (shared by every target)
         # plus the shared collector in its own folder, because its import library is also named
         # gc.lib: gcdll/gc.lib + gcdll/gc.dll, for programs that load a tslang shared library.
         # tsbindgen looks for clang's resource directory next to itself as lib/clang/<major>
         # (findResourceDir's "release package" candidate), so stage that layout too - its headers
         # only: the official LLVM package also puts compiler-rt's libraries under
         # lib/clang/<major>/lib, which neither tsbindgen nor tslang uses.
-        # Android, per ABI (arm64-v8a, x86_64): android/<abi>/defaultlib/... (--default-lib-path=
-        # android/<abi>) and android/<abi>/lib/{libgc.a,libTypeScriptAsyncRuntime.a} (--gc-lib-path
-        # and --tslang-lib-path).
+        # Android, per ABI (arm64-v8a, x86_64): android/<abi>/lib/{libgc.a,libTypeScriptAsyncRuntime.a}
+        # (--gc-lib-path and --tslang-lib-path); its default library is in the defaultlib tree above.
         run: |
           foreach ($abi in 'arm64-v8a', 'x86_64') {
             $dest = ".\android_stage\android\$abi"
             New-Item -ItemType Directory -Force -Path "$dest\lib" | Out-Null
-            # moved, not copied: the default library's __build, packaged whole below, would carry it twice
-            Move-Item -Path "..\TypeScriptCompilerDefaultLib\__build\android\$abi\defaultlib" -Destination $dest -ErrorAction Stop
             Copy-Item -Path "..\3rdParty\gc\android\$abi\release\lib\libgc.a", ".\tslang-runtime\release\android\$abi\libTypeScriptAsyncRuntime.a" -Destination "$dest\lib" -ErrorAction Stop
           }
-          Remove-Item -Recurse -Force -Path "..\TypeScriptCompilerDefaultLib\__build\android" -ErrorAction Stop
           New-Item -ItemType Directory -Force -Path .\gcdll_stage\gcdll | Out-Null
           Copy-Item -Path ..\3rdParty\gcdll\x64\release\lib\gc.lib, ..\3rdParty\gcdll\x64\release\bin\gc.dll -Destination .\gcdll_stage\gcdll -ErrorAction Stop
           Get-ChildItem -Path ..\3rdParty\llvm\x64\release\lib\clang -Directory | ForEach-Object { $dest = ".\resourcedir_stage\lib\clang\$($_.Name)"; New-Item -ItemType Directory -Force -Path $dest | Out-Null; Copy-Item -Path (Join-Path $_.FullName "include") -Destination $dest -Recurse -ErrorAction Stop }
@@ -453,8 +449,9 @@ jobs:
           cp ./gc/ninja/release/libgc.a ./__stage/
           cp ./tslang/ninja/release/lib/libTypeScriptAsyncRuntime.a ./__stage/
           cp ../3rdParty/llvm/release/bin/wasm-ld ./__stage/
-          # Add the default library as a whole tree so its per-build, per-memory-model
-          # subfolders are preserved: defaultlib/{dll,lib}/{debug,release}/{gc,rc,none},
+          # Add the default library as a whole tree so its per-target, per-build, per-memory-model
+          # subfolders are preserved:
+          # defaultlib/{dll,lib}/<arch>/<vendor>/<os>/<env>/{debug,release}/{gc,rc,none},
           # defaultlib/*.d.ts, defaultlib/generics/
           cp -r ../TypeScriptCompilerDefaultLib/__build/defaultlib ./__stage/
           # tsbindgen looks for clang's resource directory next to itself as lib/clang/<major>

diff --git a/docs/how/cmake_bgfx/README.md b/docs/how/cmake_bgfx/README.md
@@ -109,7 +109,8 @@ build matching the model it was compiled with. One variable drives both:
 cmake --preset default -DTSLANG_MEMORY_MODEL=rc
 ```
 
-It selects `defaultlib/lib/<debug|release>/<model>` as the link directory and adds `-mm=<model>`
+It selects `defaultlib/lib/<arch>/<vendor>/<os>/<env>/<debug|release>/<model>` (as
+`tslang --print-default-lib-dir=lib` names it) as the link directory and adds `-mm=<model>`
 to the compile flags, so the two cannot disagree; configuring fails if that model has not been
 built. Valid values are `gc` (default), `rc` and `none`; only `gc` links Boehm.
 

diff --git a/docs/how/cmake_bgfx/cmake/LocateTSLang.cmake b/docs/how/cmake_bgfx/cmake/LocateTSLang.cmake
@@ -113,18 +113,24 @@ function(setup_tslang_link_paths)
         message(FATAL_ERROR "setup_tslang_link_paths: TSLANG_PREFIX is not set")
     endif()
 
-    # The compiled default lib is split per build mode (debug/release) and then per memory
-    # model (gc/rc/none): a default lib built for one model allocates the way that model
-    # allocates, so linking it into a program built for another is the mismatch the compiler
-    # refuses to paper over. TSLANG_MEMORY_MODEL picks both this directory and the -mm= flag.
+    # The compiled default lib is split per target, then per build mode (debug/release), then
+    # per memory model (gc/rc/none): a default lib built for one model allocates the way that
+    # model allocates, so linking it into a program built for another is the mismatch the
+    # compiler refuses to paper over. TSLANG_MEMORY_MODEL picks both this directory and the -mm=
+    # flag; tslang names the directory (--print-default-lib-dir), so the layout is not spelled
+    # out here.
     if(CMAKE_BUILD_TYPE STREQUAL "Release")
-        set(_defaultlib_config "release")
+        set(_defaultlib_build_flag "")
     else()
-        set(_defaultlib_config "debug")
+        set(_defaultlib_build_flag "--di")
     endif()
 
-    set(_defaultlib_dir
-        "${TSLANG_BIN_DIR}/defaultlib/lib/${_defaultlib_config}/${TSLANG_MEMORY_MODEL}")
+    execute_process(COMMAND "${CMAKE_TSLANG_COMPILER}" --print-default-lib-dir=lib ${_defaultlib_build_flag}
+                            -mm=${TSLANG_MEMORY_MODEL}
+        OUTPUT_VARIABLE _defaultlib_subdir
+        OUTPUT_STRIP_TRAILING_WHITESPACE
+        COMMAND_ERROR_IS_FATAL ANY)
+    set(_defaultlib_dir "${TSLANG_BIN_DIR}/${_defaultlib_subdir}")
     if(NOT IS_DIRECTORY "${_defaultlib_dir}")
         message(FATAL_ERROR
             "No default library built for -mm=${TSLANG_MEMORY_MODEL}: ${_defaultlib_dir} "

diff --git a/docs/how/cmake_dll/CMakeLists.txt b/docs/how/cmake_dll/CMakeLists.txt
@@ -11,21 +11,27 @@ enable_language(TSLANG)
 # Include folders
 include_directories(${CMAKE_TSLANG_DIR}/defaultlib)
 
-# The compiled default lib is split into per-build subfolders (debug/release) and then per
-# memory model (gc/rc/none); pick the pair matching this build, so that the CRT, the allocator
-# and the default-lib binaries all agree. A library built for one model cannot be linked into
-# a program built for another.
+# The compiled default lib is split per target, then per build (debug/release), then per memory
+# model (gc/rc/none); pick the one matching this build, so that the CRT, the allocator and the
+# default-lib binaries all agree. A library built for one model cannot be linked into a program
+# built for another. tslang names the folder (--print-default-lib-dir), so this never spells out
+# the layout.
 if (CMAKE_BUILD_TYPE STREQUAL "Release")
-	set(TSLANG_DEFAULTLIB_BUILD "release")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "")
 else()
-	set(TSLANG_DEFAULTLIB_BUILD "debug")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "--di")
 endif()
 
 set(TSLANG_MEMORY_MODEL "gc" CACHE STRING "Memory model of compiled code: gc, rc or none")
 set_property(CACHE TSLANG_MEMORY_MODEL PROPERTY STRINGS gc rc none)
 
+execute_process(COMMAND "${CMAKE_TSLANG_COMPILER}" --print-default-lib-dir=lib ${TSLANG_DEFAULTLIB_BUILD_FLAG} -mm=${TSLANG_MEMORY_MODEL}
+	OUTPUT_VARIABLE TSLANG_DEFAULTLIB_SUBDIR
+	OUTPUT_STRIP_TRAILING_WHITESPACE
+	COMMAND_ERROR_IS_FATAL ANY)
+
 # Lib folders
-link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/defaultlib/lib/${TSLANG_DEFAULTLIB_BUILD}/${TSLANG_MEMORY_MODEL})
+link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/${TSLANG_DEFAULTLIB_SUBDIR})
 
 # set options
 if (CMAKE_BUILD_TYPE STREQUAL "Release")

diff --git a/docs/how/cmake_dll/README.md b/docs/how/cmake_dll/README.md
@@ -52,7 +52,8 @@ the build matching the model it was compiled with. One variable drives both:
 cmake --preset default -DTSLANG_MEMORY_MODEL=rc
 ```
 
-It selects `defaultlib/lib/<debug|release>/<model>` as the link directory and adds `-mm=<model>`
+It selects `defaultlib/lib/<arch>/<vendor>/<os>/<env>/<debug|release>/<model>` (as
+`tslang --print-default-lib-dir=lib` names it) as the link directory and adds `-mm=<model>`
 to the compile flags, so the two cannot disagree. Valid values are `gc` (default), `rc` and
 `none`; only `gc` links Boehm.
 

diff --git a/docs/how/cmake_tslang/CMakeLists.txt b/docs/how/cmake_tslang/CMakeLists.txt
@@ -11,14 +11,15 @@ enable_language(TSLANG)
 # Include folders
 include_directories(${CMAKE_TSLANG_DIR}/defaultlib)
 
-# The compiled default lib is split into per-build subfolders (debug/release) and then per
-# memory model (gc/rc/none); pick the pair matching this build, so that the CRT, the allocator
-# and the default-lib binaries all agree. A library built for one model cannot be linked into
-# a program built for another.
+# The compiled default lib is split per target, then per build (debug/release), then per memory
+# model (gc/rc/none); pick the one matching this build, so that the CRT, the allocator and the
+# default-lib binaries all agree. A library built for one model cannot be linked into a program
+# built for another. tslang names the folder (--print-default-lib-dir), so this never spells out
+# the layout.
 if (CMAKE_BUILD_TYPE STREQUAL "Release")
-	set(TSLANG_DEFAULTLIB_BUILD "release")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "")
 else()
-	set(TSLANG_DEFAULTLIB_BUILD "debug")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "--di")
 endif()
 
 set(TSLANG_MEMORY_MODEL "gc" CACHE STRING "Memory model of compiled code: gc, rc or none")
@@ -30,8 +31,13 @@ set_property(CACHE TSLANG_MEMORY_MODEL PROPERTY STRINGS gc rc none)
 # Two collectors free each other's live objects. See docs/memory-models.md.
 option(TSLANG_SHARED_GC "The program loads tslang shared libraries (gc: share one collector)" OFF)
 
+execute_process(COMMAND "${CMAKE_TSLANG_COMPILER}" --print-default-lib-dir=lib ${TSLANG_DEFAULTLIB_BUILD_FLAG} -mm=${TSLANG_MEMORY_MODEL}
+	OUTPUT_VARIABLE TSLANG_DEFAULTLIB_SUBDIR
+	OUTPUT_STRIP_TRAILING_WHITESPACE
+	COMMAND_ERROR_IS_FATAL ANY)
+
 # Lib folders
-link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/defaultlib/lib/${TSLANG_DEFAULTLIB_BUILD}/${TSLANG_MEMORY_MODEL})
+link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/${TSLANG_DEFAULTLIB_SUBDIR})
 
 # set options
 if (CMAKE_BUILD_TYPE STREQUAL "Release")

diff --git a/docs/how/cmake_tslang/README.md b/docs/how/cmake_tslang/README.md
@@ -52,7 +52,8 @@ the build matching the model it was compiled with. One variable drives both:
 cmake --preset default -DTSLANG_MEMORY_MODEL=rc
 ```
 
-It selects `defaultlib/lib/<debug|release>/<model>` as the link directory and adds `-mm=<model>`
+It selects `defaultlib/lib/<arch>/<vendor>/<os>/<env>/<debug|release>/<model>` (as
+`tslang --print-default-lib-dir=lib` names it) as the link directory and adds `-mm=<model>`
 to the compile flags, so the two cannot disagree. Valid values are `gc` (default), `rc` and
 `none`; only `gc` links Boehm.
 
@@ -69,7 +70,7 @@ cmake --preset default -DTSLANG_SHARED_GC=ON
 
 - Windows: links `gcdll/gc.lib` (gc.dll's import library) instead of the static `gc.lib`, and copies
   `gc.dll` beside the program. Ship it with `TypeScriptDefaultLib.dll`
-  (`defaultlib/dll/<release|debug>/gc`) and your libraries.
+  (`defaultlib/dll/<arch>/<vendor>/<os>/<env>/<release|debug>/gc`) and your libraries.
 - Linux: links the whole static collector and exports its `GC_*` symbols, so the shared library
   uses the program's collector.
 

diff --git a/docs/memory-models.md b/docs/memory-models.md
@@ -150,7 +150,8 @@ What to ship with a Windows program that loads a tslang shared library, all in o
 
 - the program and its shared libraries,
 - `gc.dll` (from `gcdll/` in the release package),
-- `TypeScriptDefaultLib.dll` (from `defaultlib/dll/<release|debug>/gc`), which every shared library
+- `TypeScriptDefaultLib.dll` (from `defaultlib/dll/x86_64/pc/windows/msvc/<release|debug>/gc`;
+  `tslang --print-default-lib-dir=dll [--di]` names it), which every shared library
   built with the default library imports.
 
 A shared library that was linked against the static `gc.lib` anyway — by an older `tslang`, or by

diff --git a/tslang/build_tslang_defaultlib_debug.bat b/tslang/build_tslang_defaultlib_debug.bat
@@ -2,8 +2,8 @@ pushd
 cd ../../TypeScriptCompilerDefaultLib/
 call build.bat
 
-rem Copy the whole staged defaultlib tree so per-build subfolders are preserved:
-rem defaultlib\dll\{debug,release}\{gc,rc,none}, defaultlib\lib\{debug,release}\{gc,rc,none},
+rem Copy the whole staged defaultlib tree so every target's, build's and model's subfolders are
+rem preserved: defaultlib\{dll,lib}\<arch>\<vendor>\<os>\<env>\{debug,release}\{gc,rc,none},
 rem *.d.ts, generics\
 xcopy __build\defaultlib\*.* "../TypeScriptCompiler/__build/tslang/windows-msbuild-2026-debug/bin/defaultlib/" /i /e /y
 

diff --git a/tslang/build_tslang_defaultlib_release.bat b/tslang/build_tslang_defaultlib_release.bat
@@ -2,8 +2,8 @@ pushd
 cd ../../TypeScriptCompilerDefaultLib/
 call build.bat
 
-rem Copy the whole staged defaultlib tree so per-build subfolders are preserved:
-rem defaultlib\dll\{debug,release}\{gc,rc,none}, defaultlib\lib\{debug,release}\{gc,rc,none},
+rem Copy the whole staged defaultlib tree so every target's, build's and model's subfolders are
+rem preserved: defaultlib\{dll,lib}\<arch>\<vendor>\<os>\<env>\{debug,release}\{gc,rc,none},
 rem *.d.ts, generics\
 xcopy __build\defaultlib\*.* "../TypeScriptCompiler/__build/tslang/windows-msbuild-2026-release/bin/defaultlib/" /i /e /y
 

diff --git a/tslang/include/TypeScript/Defines.h b/tslang/include/TypeScript/Defines.h
@@ -318,27 +318,23 @@
 // warns about, and it is the largest instance of it, since every program that does not pass
 // `--no-default-lib` links this one.
 //
-// Layout: defaultlib/{lib,dll}/[x86/]{debug,release}/{gc,rc,none}/. The model name is exactly
-// `memoryModelName()`, so the directory and the `-mm=` flag cannot drift apart.
+// The model name is exactly `memoryModelName()`, so the directory and the `-mm=` flag cannot
+// drift apart.
 #define DEFAULT_LIB_KIND_STATIC "lib"
 #define DEFAULT_LIB_KIND_SHARED "dll"
 
-// ...and, for a Windows x86 target, per arch, outermost under lib/ or dll/ like every other x86
-// library (spec "Arch in the library layout"). Every other target, x64 included, has no arch
-// segment, so existing trees keep their shape. There is no fallback to the x64 tree: an x64
-// library links into an x86 program only to fail on every symbol.
-#define DEFAULT_LIB_ARCH_X86 "x86"
-
-inline std::string getDefaultLibSubDir(bool shared, bool debugBuild, const char *memoryModel, const char *arch)
-{
-    std::string subDir = std::string(DEFAULT_LIB_DIR "/") + (shared ? DEFAULT_LIB_KIND_SHARED : DEFAULT_LIB_KIND_STATIC) + "/";
-    if (arch && *arch)
-    {
-        subDir += std::string(arch) + "/";
-    }
-
-    return subDir + (debugBuild ? DEFAULT_LIB_BUILD_DIR_DEBUG : DEFAULT_LIB_BUILD_DIR_RELEASE) + "/" + memoryModel;
-}
+// ...and, outermost under lib/ or dll/, per target, as the LLVM triple names it: arch, vendor, OS
+// and environment, each the canonical name LLVM gives the parsed component, so the spellings of
+// one target (i686/i386, an Android API level, an MSVC version) share a tree. Every target is
+// keyed this way, the host included. There is no fallback to another target's tree: a library
+// built for one links into a program for another only to fail on every symbol.
+//
+// Layout: defaultlib/{lib,dll}/<arch>/<vendor>/<os>/<env>/{debug,release}/{gc,rc,none}/, e.g.
+// defaultlib/lib/x86_64/pc/windows/msvc/release/gc or defaultlib/lib/aarch64/unknown/linux/android/
+// release/gc. Everything else (*.d.ts, generics/, ...) stays at the defaultlib root, shared by
+// every build. Composed in ONE place, getDefaultLibSubDir (tslang/tslang/defaultlib.cpp), which
+// the linker, the JIT, --install-default-lib and --print-default-lib-dir all call; the build
+// scripts ask --print-default-lib-dir rather than spelling the path out.
 
 #define DEBUG_SCOPE "current"
 #define CU_DEBUG_SCOPE "compileUnit"

diff --git a/tslang/include/TypeScript/VSCodeTemplate/Files.h b/tslang/include/TypeScript/VSCodeTemplate/Files.h
@@ -301,21 +301,27 @@ project(<<PROJECT>> CXX TSLANG)
 # Include folders
 include_directories(${CMAKE_TSLANG_DIR}/defaultlib)
 
-# The compiled default lib is split into per-build subfolders (debug/release) and then per
-# memory model (gc/rc/none); pick the pair matching this build, so that the CRT, the allocator
-# and the default-lib binaries all agree. A library built for one model cannot be linked into
-# a program built for another.
+# The compiled default lib is split per target, then per build (debug/release), then per memory
+# model (gc/rc/none); pick the one matching this build, so that the CRT, the allocator and the
+# default-lib binaries all agree. A library built for one model cannot be linked into a program
+# built for another. tslang names the folder (--print-default-lib-dir), so this never spells out
+# the layout.
 if (CMAKE_BUILD_TYPE STREQUAL "Release")
-	set(TSLANG_DEFAULTLIB_BUILD "release")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "")
 else()
-	set(TSLANG_DEFAULTLIB_BUILD "debug")
+	set(TSLANG_DEFAULTLIB_BUILD_FLAG "--di")
 endif()
 
 set(TSLANG_MEMORY_MODEL "gc" CACHE STRING "Memory model of compiled code: gc, rc or none")
 set_property(CACHE TSLANG_MEMORY_MODEL PROPERTY STRINGS gc rc none)
 
+execute_process(COMMAND "${CMAKE_TSLANG_COMPILER}" --print-default-lib-dir=lib ${TSLANG_DEFAULTLIB_BUILD_FLAG} -mm=${TSLANG_MEMORY_MODEL}
+	OUTPUT_VARIABLE TSLANG_DEFAULTLIB_SUBDIR
+	OUTPUT_STRIP_TRAILING_WHITESPACE
+	COMMAND_ERROR_IS_FATAL ANY)
+
 # Lib folders
-link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/defaultlib/lib/${TSLANG_DEFAULTLIB_BUILD}/${TSLANG_MEMORY_MODEL})
+link_directories(${CMAKE_TSLANG_DIR} ${CMAKE_TSLANG_DIR}/${TSLANG_DEFAULTLIB_SUBDIR})
 
 # set options
 if (CMAKE_BUILD_TYPE STREQUAL "Release")
@@ -480,7 +486,8 @@ the build matching the model it was compiled with. One variable drives both:
 cmake --preset default -DTSLANG_MEMORY_MODEL=rc
 ```
 
-It selects `defaultlib/lib/<debug|release>/<model>` as the link directory and adds `-mm=<model>`
+It selects `defaultlib/lib/<arch>/<vendor>/<os>/<env>/<debug|release>/<model>` (as
+`tslang --print-default-lib-dir=lib` names it) as the link directory and adds `-mm=<model>`
 to the compile flags, so the two cannot disagree. Valid values are `gc` (default), `rc` and
 `none`; only `gc` links Boehm.