Default library binaries split by target triple, then build, then memory model

[ASDAlexander77]

Summary

The compiled default library is now split by target triple for every target (the host included), then by build mode, then by memory model:

defaultlib/{lib,dll}/<arch>/<vendor>/<os>/<env>/{debug,release}/{gc,rc,none}/
  x64 Windows  x86_64/pc/windows/msvc      x86 Windows  i386/pc/windows/msvc
  Linux        x86_64/unknown/linux/gnu    Android      aarch64|x86_64/unknown/linux/android
defaultlib/*.d.ts, generics/, ...          shared by every build

• Each segment is LLVM's canonical name for the parsed triple component (getArchTypeName etc.), so i686/i386, an Android API level (android29) or an MSVC version share one tree. The x86 arch is therefore i386. The environment is included because Android's OS is linux: without it Android and glibc Linux would collide.
• Everything other than the binaries stays at the defaultlib root, common to all builds. Android no longer has its own __build/android/<abi>/defaultlib tree: it takes --default-lib-path=<the folder holding defaultlib> like every other target.
• getDefaultLibSubDir moves from Defines.h (which the async runtime includes without LLVM) to defaultlib.cpp and takes an llvm::Triple. The linker (exe.cpp), the JIT (host triple), --install-default-lib and the new option all call it. The old DEFAULT_LIB_ARCH_X86 special case is gone.
• New tslang --print-default-lib-dir=<lib|dll> [-mtriple=...] [--di] -mm=<model> prints the folder. Build scripts, CMake templates and tests ask it instead of spelling the layout out, so producer and consumer cannot drift. test-default-lib-dir pins the strings.
• The missing-library error now names the triple: no default library built for x86_64-pc-windows-msvc -mm=rc: ....

Consumers updated: defaultlib-collector.cmake, android-link.cmake, check-x86-libs.sh, check-x86-run.sh, the VSCode/CMake template in Files.h, docs/how/cmake_{tslang,dll,bgfx}, create-release.yml (the Android default library now ships in the shared defaultlib tree; android/<abi>/lib keeps only libgc.a and libTypeScriptAsyncRuntime.a).

Also: check-x86-libs.sh's stand-in default-library trees get a lib.d.ts, missing since #371 made an unreadable reference an error. Three of its cases were failing before this change.

Merge order

DefaultLib counterpart: ASDAlexander77/TypeScriptCompilerDefaultLib#30. Merge this one first: the DefaultLib build scripts call --print-default-lib-dir and refuse to run with a tslang that lacks it. Old release zips and a new compiler are incompatible (and vice versa), so the next tag needs a full default-library rebuild, which create-release.yml already does.

Test plan

• test-default-lib-dir, test-compile-android-codegen
• DefaultLib rebuilt into the new layout: x64 and x86 Windows (debug and release, gc/rc/none), Android arm64-v8a and x86_64 (all 12)
• test-jit-gc-defaultlib-collector, test-compile-gc-defaultlib-collector with TSLANG_REQUIRE_DEFAULT_LIB=1 (not skipped)
• test-compile-android-link against the shared tree (not skipped)
• check-x86-libs.sh all ok, including the x64 control against the real library
• check-x86-run.sh default-library section all ok against the i386 tree. Two unrelated failures (both --no-default-lib) are pre-existing: the -mm=none frame-allocator IR check expects aligned_alloc but frames now come from __tslang_heap_malloc, and await_order -mm=gc output order is flaky. Filed separately.
• tslang --cmake project configures and resolves defaultlib/lib/x86_64/pc/windows/msvc/release/rc for -DTSLANG_MEMORY_MODEL=rc
• Linux: DefaultLib scripts/build.sh only syntax-checked locally; the build_on_linux release job is the real test

🤖 Generated with Claude Code