[clang] [WebAssembly] Change the default linker for `wasm32-wasip2` (PR #84569)
Alex Crichton via cfe-commits
cfe-commits at lists.llvm.org
Mon Mar 18 12:25:10 PDT 2024
https://github.com/alexcrichton updated https://github.com/llvm/llvm-project/pull/84569
>From 99ca952b60344d2ff683d05d8baa423aa11da83a Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex at alexcrichton.com>
Date: Fri, 8 Mar 2024 13:36:18 -0800
Subject: [PATCH 1/2] [WebAssembly] Change the default linker for
`wasm32-wasip2`
This commit changes the default linker in the WebAssembly toolchain for
the `wasm32-wasip2` target. This target is being added to the
WebAssembly/wasi-sdk and WebAssembly/wasi-libc projects to target the
Component Model by default, in contrast with the preexisting
`wasm32-wasi` target (in the process of being renamed to
`wasm32-wasip1`) which outputs a core WebAssembly module by default.
The `wasm-component-ld` project currently lives in my GitHub account at
https://github.com/alexcrichton/wasm-component-ld and isn't necessarily
"official" yet, but it's expected to continue to evolve as the
`wasm32-wasip2` target continues to shape up and evolve.
---
clang/lib/Driver/ToolChains/WebAssembly.cpp | 6 ++++++
clang/lib/Driver/ToolChains/WebAssembly.h | 2 +-
clang/test/Driver/wasm-toolchain.c | 8 ++++++++
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp
index b8c2573d6265fb..a6c43c627f7206 100644
--- a/clang/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -221,6 +221,12 @@ WebAssembly::WebAssembly(const Driver &D, const llvm::Triple &Triple,
}
}
+const char *WebAssembly::getDefaultLinker() const {
+ if (getOS() == "wasip2")
+ return "wasm-component-ld";
+ return "wasm-ld";
+}
+
bool WebAssembly::IsMathErrnoDefault() const { return false; }
bool WebAssembly::IsObjCNonFragileABIDefault() const { return true; }
diff --git a/clang/lib/Driver/ToolChains/WebAssembly.h b/clang/lib/Driver/ToolChains/WebAssembly.h
index ae60f464c10818..76e0ca39bd748d 100644
--- a/clang/lib/Driver/ToolChains/WebAssembly.h
+++ b/clang/lib/Driver/ToolChains/WebAssembly.h
@@ -67,7 +67,7 @@ class LLVM_LIBRARY_VISIBILITY WebAssembly final : public ToolChain {
llvm::opt::ArgStringList &CmdArgs) const override;
SanitizerMask getSupportedSanitizers() const override;
- const char *getDefaultLinker() const override { return "wasm-ld"; }
+ const char *getDefaultLinker() const override;
CXXStdlibType GetDefaultCXXStdlibType() const override {
return ToolChain::CST_Libcxx;
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
index f950283ec42aa0..59cfdfb3cb113b 100644
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/test/Driver/wasm-toolchain.c
@@ -197,3 +197,11 @@
// RUN: not %clang -### %s --target=wasm32-unknown-unknown --sysroot=%s/no-sysroot-there -fPIC -mno-mutable-globals %s 2>&1 \
// RUN: | FileCheck -check-prefix=PIC_NO_MUTABLE_GLOBALS %s
// PIC_NO_MUTABLE_GLOBALS: error: invalid argument '-fPIC' not allowed with '-mno-mutable-globals'
+
+// Test that `wasm32-wasip2` invokes the `wasm-component-ld` linker by default
+// instead of `wasm-ld`.
+
+// RUN: %clang -### -O2 --target=wasm32-wasip2 %s --sysroot /foo 2>&1 \
+// RUN: | FileCheck -check-prefix=LINK_WASIP2 %s
+// LINK_WASIP2: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
+// LINK_WASIP2: wasm-component-ld{{.*}}" "-L/foo/lib/wasm32-wasip2" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
>From d1a1b22da3e1361a34f2d4fa8a2f9ef361f109ee Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex at alexcrichton.com>
Date: Mon, 18 Mar 2024 12:23:23 -0700
Subject: [PATCH 2/2] Pass a path to `wasm-ld` to `wasm-component-ld`
This commit adds an explicit argument that's passed to
`wasm-component-ld` containing the location of `wasm-ld` itself. This
enables `wasm-component-ld` to avoid hunting around looking for it and
instead use the install that's paired with Clang itself.
Additionally this reinterprets the `-fuse-ld=lld` argument to explicitly
requesting the `wasm-ld` linker flavor, even on `wasm32-wasip2` targets.
---
clang/lib/Driver/ToolChains/WebAssembly.cpp | 20 ++++++++++++++++++--
clang/test/Driver/wasm-toolchain.c | 16 ++++++++++++++++
2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/WebAssembly.cpp b/clang/lib/Driver/ToolChains/WebAssembly.cpp
index a6c43c627f7206..61bf9d8aae72d2 100644
--- a/clang/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/clang/lib/Driver/ToolChains/WebAssembly.cpp
@@ -44,8 +44,15 @@ std::string wasm::Linker::getLinkerPath(const ArgList &Args) const {
llvm::sys::fs::can_execute(UseLinker))
return std::string(UseLinker);
- // Accept 'lld', and 'ld' as aliases for the default linker
- if (UseLinker != "lld" && UseLinker != "ld")
+ // Interpret 'lld' as explicitly requesting `wasm-ld`, so look for that
+ // linker. Note that for `wasm32-wasip2` this overrides the default linker
+ // of `wasm-component-ld`.
+ if (UseLinker == "lld") {
+ return ToolChain.GetProgramPath("wasm-ld");
+ }
+
+ // Allow 'ld' as an alias for the default linker
+ if (UseLinker != "ld")
ToolChain.getDriver().Diag(diag::err_drv_invalid_linker_name)
<< A->getAsString(Args);
}
@@ -73,6 +80,15 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (Args.hasArg(options::OPT_s))
CmdArgs.push_back("--strip-all");
+ // On `wasip2` the default linker is `wasm-component-ld` which wraps the
+ // execution of `wasm-ld`. Find `wasm-ld` and pass it as an argument of where
+ // to find it to avoid it needing to hunt and rediscover or search `PATH` for
+ // where it is.
+ if (llvm::sys::path::stem(Linker).ends_with_insensitive("wasm-component-ld")) {
+ CmdArgs.push_back("--wasm-ld-path");
+ CmdArgs.push_back(Args.MakeArgString(ToolChain.GetProgramPath("wasm-ld")));
+ }
+
Args.addAllArgs(CmdArgs, {options::OPT_L, options::OPT_u});
ToolChain.AddFilePathLibArgs(Args, CmdArgs);
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
index 59cfdfb3cb113b..88590a3ba4c453 100644
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/test/Driver/wasm-toolchain.c
@@ -205,3 +205,19 @@
// RUN: | FileCheck -check-prefix=LINK_WASIP2 %s
// LINK_WASIP2: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_WASIP2: wasm-component-ld{{.*}}" "-L/foo/lib/wasm32-wasip2" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"
+
+// Test that on `wasm32-wasip2` the `wasm-component-ld` programs is told where
+// to find `wasm-ld` by default.
+
+// RUN: %clang -### -O2 --target=wasm32-wasip2 %s --sysroot /foo 2>&1 \
+// RUN: | FileCheck -check-prefix=LINK_WASIP2_FIND_WASMLD %s
+// LINK_WASIP2_FIND_WASMLD: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
+// LINK_WASIP2_FIND_WASMLD: wasm-component-ld{{.*}}" {{.*}} "--wasm-ld-path" "{{.*}}wasm-ld{{.*}}" {{.*}} "[[temp]]" {{.*}}
+
+// If `wasm32-wasip2` is configured with `wasm-ld` as a linker then don't pass
+// the `--wasm-ld-path` flag.
+
+// RUN: %clang -### -O2 --target=wasm32-wasip2 -fuse-ld=lld %s --sysroot /foo 2>&1 \
+// RUN: | FileCheck -check-prefix=LINK_WASIP2_USE_WASMLD %s
+// LINK_WASIP2_USE_WASMLD: "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
+// LINK_WASIP2_USE_WASMLD: wasm-ld{{.*}}" "-m" "wasm32" {{.*}} "[[temp]]" {{.*}}
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