Author: Joel Dice Date: 2023-06-26T10:31:40-07:00 New Revision: 55e199a2c9f4b218499733d60129deffa0a025fe
URL: https://github.com/llvm/llvm-project/commit/55e199a2c9f4b218499733d60129deffa0a025fe DIFF: https://github.com/llvm/llvm-project/commit/55e199a2c9f4b218499733d60129deffa0a025fe.diff LOG: [clang][WebAssembly] Support wasm32-wasi shared libraries This adds support for Emscripten-style shared libraries [1] to non-emscripten targets, such as `wasm32-wasi`. Previously, only static linking was supported, and the `-shared` and `-fPIC` flags were simply ignored. Now both flags are honored. Since WASI runtimes do not necessarily include JavaScript support, we cannot rely on the JS-based Emscripten linker to link shared libraries. Instead, we link them using the Component Model proposal [2]. We have prototyped shared library support in `wasi-sdk` [3] and put together a demo [4] which uses a patched version of `wit-component` [5] to link libraries using the Component Model. We plan to submit the required changes upstream to the respective repositories in the next week or two. [1] https://github.com/WebAssembly/tool-conventions/blob/main/DynamicLinking.md [2] https://github.com/WebAssembly/component-model/blob/main/design/mvp/examples/SharedEverythingDynamicLinking.md [3] https://github.com/dicej/wasi-sdk/tree/dynamic-linking [4] https://github.com/dicej/component-linking-demo [5] https://github.com/bytecodealliance/wasm-tools/tree/main/crates/wit-component Signed-off-by: Joel Dice <joel.d...@fermyon.com> Reviewed By: sbc100 Differential Revision: https://reviews.llvm.org/D153293 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/Driver/ToolChains/WebAssembly.cpp clang/test/Driver/wasm-toolchain.c llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 055aa9008b03b..c022e9ffb6604 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -727,6 +727,12 @@ AIX Support WebAssembly Support ^^^^^^^^^^^^^^^^^^^ +- Shared library support (and PIC code generation) for WebAssembly is no longer + limited to the Emscripten target OS and now works with other targets such as + wasm32-wasi. Note that the `format + <https://github.com/WebAssembly/tool-conventions/blob/main/DynamicLinking.md>`_ + is not yet stable and may change between LLVM versions. Also, WASI does not + yet have facilities to load dynamic libraries. AVR Support ^^^^^^^^^^^ diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp index 016b70b1c2ede..fb9c8e4910e8b 100644 --- a/clang/lib/Driver/ToolChains/WebAssembly.cpp +++ b/clang/lib/Driver/ToolChains/WebAssembly.cpp @@ -101,13 +101,16 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA, << CM << A->getOption().getName(); } } - if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) + if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles, options::OPT_shared)) CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(Crt1))); if (Entry) { CmdArgs.push_back(Args.MakeArgString("--entry")); CmdArgs.push_back(Args.MakeArgString(Entry)); } + if (Args.hasArg(options::OPT_shared)) + CmdArgs.push_back(Args.MakeArgString("-shared")); + AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA); if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) { diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c index bfe696d7846e7..909d27f0f2d9c 100644 --- a/clang/test/Driver/wasm-toolchain.c +++ b/clang/test/Driver/wasm-toolchain.c @@ -33,6 +33,20 @@ // LINK_KNOWN: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]" // LINK_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out" +// -shared should be passed through to `wasm-ld` and not include crt1.o with a known OS. + +// RUN: %clang -### -shared --target=wasm32-wasi --sysroot=/foo %s 2>&1 \ +// RUN: | FileCheck -check-prefix=LINK_KNOWN_SHARED %s +// LINK_KNOWN_SHARED: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]" +// LINK_KNOWN_SHARED: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out" + +// -shared should be passed through to `wasm-ld` and not include crt1.o with an unknown OS. + +// RUN: %clang -### -shared --target=wasm32-unknown-unknown --sysroot=/foo %s 2>&1 \ +// RUN: | FileCheck -check-prefix=LINK_UNKNOWN_SHARED %s +// LINK_UNKNOWN_SHARED: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]" +// LINK_UNKNOWN_SHARED: wasm-ld{{.*}}" "-shared" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out" + // A basic C link command-line with optimization with known OS. // RUN: %clang -### -O2 --target=wasm32-wasi --sysroot=/foo %s 2>&1 \ @@ -46,6 +60,18 @@ // RUN: | FileCheck -check-prefix=COMPILE %s // COMPILE: "-cc1" {{.*}} "-internal-isystem" "/foo/include/wasm32-wasi" "-internal-isystem" "/foo/include" +// -fPIC should work on a known OS + +// RUN: %clang -### -fPIC --target=wasm32-wasi --sysroot=/foo %s 2>&1 \ +// RUN: | FileCheck -check-prefix=COMPILE_KNOWN_PIC %s +// COMPILE_KNOWN_PIC: "-cc1" {{.*}} "-mrelocation-model" "pic" "-pic-level" "2" {{.*}} "-internal-isystem" "/foo/include/wasm32-wasi" "-internal-isystem" "/foo/include" + +// -fPIC should work on an unknown OS + +// RUN: %clang -### -fPIC --target=wasm32-unknown-unknown --sysroot=/foo %s 2>&1 \ +// RUN: | FileCheck -check-prefix=COMPILE_UNKNOWN_PIC %s +// COMPILE_UNKNOWN_PIC: "-cc1" {{.*}} "-mrelocation-model" "pic" "-pic-level" "2" + // Thread-related command line tests. // '-pthread' sets +atomics, +bulk-memory, +mutable-globals, +sign-ext, and --shared-memory diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp index c10f07018878b..6ef219f216a3b 100644 --- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp +++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp @@ -99,13 +99,6 @@ static Reloc::Model getEffectiveRelocModel(std::optional<Reloc::Model> RM, return Reloc::Static; } - if (!TT.isOSEmscripten()) { - // Relocation modes other than static are currently implemented in a way - // that only works for Emscripten, so disable them if we aren't targeting - // Emscripten. - return Reloc::Static; - } - return *RM; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
