internal/rosa: patch library paths

This removes the need for reference LDFLAGS in the standard toolchain.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/busybox.go

@@ -297,7 +297,6 @@ config_disable() {
 cat > /bin/gcc << EOF
 exec clang \
 	-Wno-ignored-optimization-argument \
-	${ROSA_CFLAGS} \
 	${LDFLAGS} \
 	\$@
 EOF

internal/rosa/go.go

@@ -51,7 +51,6 @@ func (t Toolchain) newGo(
 		"CC=cc",
 		"GOCACHE=/tmp/gocache",
 		"GOROOT_BOOTSTRAP=/system/go",
-		"CGO_" + ldflags(false) + " -O2 -g",
 	}, env), `
 mkdir /work/system
 cp -r /usr/src/go /work/system

internal/rosa/kernel.go

@@ -19,7 +19,6 @@ func (t Toolchain) newKernel(
 		t.NewMake(),
 	}, extra), nil, nil, `
 export LLVM=1
-export HOSTCFLAGS="${ROSA_CFLAGS}"
 export HOSTLDFLAGS="${LDFLAGS}"
 chmod -R +w /usr/src/linux && cd /usr/src/linux
 `+script, pkg.Path(AbsUsrSrc.Append("linux"), true, pkg.NewHTTPGetTar(

internal/rosa/llvm.go

@@ -140,8 +140,10 @@ func (t Toolchain) newLLVM(variant string, attr *llvmAttr) pkg.Artifact {
 
 	if attr.flags&llvmProjectClang != 0 {
 		cache = append(cache,
+			[2]string{"CLANG_DEFAULT_LINKER", "lld"},
 			[2]string{"CLANG_DEFAULT_CXX_STDLIB", "libc++"},
 			[2]string{"CLANG_DEFAULT_RTLIB", "compiler-rt"},
+			[2]string{"CLANG_DEFAULT_UNWINDLIB", "libunwind"},
 		)
 	}
 	if attr.flags&llvmProjectLld != 0 {
@@ -237,10 +239,15 @@ func (t Toolchain) NewLLVM() (musl, compilerRT, runtimes, clang pkg.Artifact) {
 		{"LLVM_ENABLE_LIBXML2", "OFF"},
 	}
 
+	var env []string
+	if t == toolchainStage3 {
+		env = []string{
+			"LDFLAGS=" + earlyLDFLAGS(false),
+		}
+	}
+
 	compilerRT = t.newLLVM("compiler-rt", &llvmAttr{
-		env: []string{
+		env: env,
-			ldflags(false),
-		},
 		cmake: [][2]string{
 			// libc++ not yet available
 			{"CMAKE_CXX_COMPILER_TARGET", ""},
@@ -281,20 +288,17 @@ ln -s \
 
 	musl = t.NewMusl(&MuslAttr{
 		Extra: []pkg.Artifact{compilerRT},
-		Env: []string{
+		Env: slices.Concat(env, []string{
-			ldflags(false),
 			"CC=clang",
 			"LIBCC=/system/lib/clang/21/lib/" +
 				triplet() + "/libclang_rt.builtins.a",
 			"AR=ar",
 			"RANLIB=ranlib",
-		},
+		}),
 	})
 
 	runtimes = t.newLLVM("runtimes", &llvmAttr{
-		env: []string{
+		env:   env,
-			ldflags(false),
-		},
 		flags: llvmRuntimeLibunwind | llvmRuntimeLibcxx | llvmRuntimeLibcxxABI,
 		cmake: slices.Concat([][2]string{
 			// libc++ not yet available
@@ -320,9 +324,7 @@ ln -s \
 
 	clang = t.newLLVM("clang", &llvmAttr{
 		flags: llvmProjectClang | llvmProjectLld,
-		env: slices.Concat(clangExtraEnv, []string{
+		env:   slices.Concat(clangExtraEnv, env),
-			ldflags(false),
-		}),
 		cmake: slices.Concat([][2]string{
 			{"LLVM_TARGETS_TO_BUILD", target},
 			{"CMAKE_CROSSCOMPILING", "OFF"},
@@ -342,17 +344,7 @@ ninja check-all
 `,
 
 		patches: [][2]string{
-			{"xfail-broken-tests", `diff --git a/clang/test/Driver/hexagon-toolchain-linux.c b/clang/test/Driver/hexagon-toolchain-linux.c
+			{"xfail-broken-tests", `diff --git a/clang/test/Modules/timestamps.c b/clang/test/Modules/timestamps.c
-index e791353cca07..4efaf3948054 100644
---- a/clang/test/Driver/hexagon-toolchain-linux.c
-+++ b/clang/test/Driver/hexagon-toolchain-linux.c
-@@ -1,3 +1,5 @@
-+// XFAIL: target={{.*-rosa-linux-musl}}
-+
- // UNSUPPORTED: system-windows
-
- // -----------------------------------------------------------------------------
-diff --git a/clang/test/Modules/timestamps.c b/clang/test/Modules/timestamps.c
 index 50fdce630255..4b4465a75617 100644
 --- a/clang/test/Modules/timestamps.c
 +++ b/clang/test/Modules/timestamps.c
@@ -389,6 +381,86 @@ index cdbf21fb9026..dd052858700d 100644
 
    if (!DriverArgs.hasArg(options::OPT_nobuiltininc) && getTriple().isMusl())
      addSystemInclude(DriverArgs, CC1Args, ResourceDirInclude);
+`},
+
+			{"path-system-libraries", `diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
+index 8d3775de9be5..1e126e2d6f24 100644
+--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
++++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
+@@ -463,6 +463,15 @@ void tools::AddLinkerInputs(const ToolChain &TC, const InputInfoList &Inputs,
+   if (!TC.isCrossCompiling())
+     addDirectoryList(Args, CmdArgs, "-L", "LIBRARY_PATH");
+
++  const std::string RosaSuffix = "-rosa-linux-musl";
++  if (TC.getTripleString().size() > RosaSuffix.size() &&
++      std::equal(RosaSuffix.rbegin(), RosaSuffix.rend(), TC.getTripleString().rbegin())) {
++    CmdArgs.push_back("-rpath");
++    CmdArgs.push_back("/system/lib");
++    CmdArgs.push_back("-rpath");
++    CmdArgs.push_back(("/system/lib/" + TC.getTripleString()).c_str());
++  }
++
+   for (const auto &II : Inputs) {
+     // If the current tool chain refers to an OpenMP offloading host, we
+     // should ignore inputs that refer to OpenMP offloading devices -
+diff --git a/clang/lib/Driver/ToolChains/Linux.cpp b/clang/lib/Driver/ToolChains/Linux.cpp
+index 8ac8d4eb9181..795995bb53cb 100644
+--- a/clang/lib/Driver/ToolChains/Linux.cpp
++++ b/clang/lib/Driver/ToolChains/Linux.cpp
+@@ -324,6 +324,7 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+     Generic_GCC::AddMultilibPaths(D, SysRoot, "libo32", MultiarchTriple, Paths);
+     addPathIfExists(D, concat(SysRoot, "/libo32"), Paths);
+     addPathIfExists(D, concat(SysRoot, "/usr/libo32"), Paths);
++    addPathIfExists(D, concat(SysRoot, "/system/libo32"), Paths);
+   }
+   Generic_GCC::AddMultilibPaths(D, SysRoot, OSLibDir, MultiarchTriple, Paths);
+
+@@ -343,16 +344,20 @@ Linux::Linux(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
+
+   addPathIfExists(D, concat(SysRoot, "/usr/lib", MultiarchTriple), Paths);
+   addPathIfExists(D, concat(SysRoot, "/usr", OSLibDir), Paths);
++  addPathIfExists(D, concat(SysRoot, "/system/lib", MultiarchTriple), Paths);
++  addPathIfExists(D, concat(SysRoot, "/system", OSLibDir), Paths);
+   if (IsRISCV) {
+     StringRef ABIName = tools::riscv::getRISCVABI(Args, Triple);
+     addPathIfExists(D, concat(SysRoot, "/", OSLibDir, ABIName), Paths);
+     addPathIfExists(D, concat(SysRoot, "/usr", OSLibDir, ABIName), Paths);
++    addPathIfExists(D, concat(SysRoot, "/system", OSLibDir, ABIName), Paths);
+   }
+
+   Generic_GCC::AddMultiarchPaths(D, SysRoot, OSLibDir, Paths);
+
+   addPathIfExists(D, concat(SysRoot, "/lib"), Paths);
+   addPathIfExists(D, concat(SysRoot, "/usr/lib"), Paths);
++  addPathIfExists(D, concat(SysRoot, "/system/lib"), Paths);
+ }
+
+ ToolChain::RuntimeLibType Linux::GetDefaultRuntimeLibType() const {
+@@ -457,6 +462,11 @@ std::string Linux::getDynamicLinker(const ArgList &Args) const {
+     return Triple.isArch64Bit() ? "/system/bin/linker64" : "/system/bin/linker";
+   }
+   if (Triple.isMusl()) {
++    const std::string RosaSuffix = "-rosa-linux-musl";
++    if (Triple.str().size() > RosaSuffix.size() &&
++        std::equal(RosaSuffix.rbegin(), RosaSuffix.rend(), Triple.str().rbegin()))
++      return "/system/bin/linker";
++
+     std::string ArchName;
+     bool IsArm = false;
+
+diff --git a/clang/tools/clang-installapi/Options.cpp b/clang/tools/clang-installapi/Options.cpp
+index 64324a3f8b01..15ce70b68217 100644
+--- a/clang/tools/clang-installapi/Options.cpp
++++ b/clang/tools/clang-installapi/Options.cpp
+@@ -515,7 +515,7 @@ bool Options::processFrontendOptions(InputArgList &Args) {
+     FEOpts.FwkPaths = std::move(FrameworkPaths);
+
+   // Add default framework/library paths.
+-  PathSeq DefaultLibraryPaths = {"/usr/lib", "/usr/local/lib"};
++  PathSeq DefaultLibraryPaths = {"/usr/lib", "/system/lib", "/usr/local/lib"};
+   PathSeq DefaultFrameworkPaths = {"/Library/Frameworks",
+                                    "/System/Library/Frameworks"};
+
 `},
 		},
 	})

internal/rosa/musl.go

@@ -29,8 +29,12 @@ func (t Toolchain) NewMusl(attr *MuslAttr) pkg.Artifact {
 
 	target := "install"
 	script := `
-mv -v /work/lib/* /work/system/lib
+mkdir -p /work/system/bin
-rmdir -v /work/lib/
+COMPAT_LINKER_NAME="ld-musl-$(uname -m).so.1"
+ln -vs ../lib/libc.so /work/system/bin/linker
+ln -vs libc.so "/work/system/lib/${COMPAT_LINKER_NAME}"
+rm -v "/work/lib/${COMPAT_LINKER_NAME}"
+rmdir -v /work/lib
 `
 	if attr.Headers {
 		target = "install-headers"

internal/rosa/python.go

@@ -39,6 +39,10 @@ func (t Toolchain) NewPython() pkg.Artifact {
 		t.NewLibffi(),
 	}, nil, []string{
 		"EXTRATESTOPTS=-j0 -x " + strings.Join(skipTests, " -x "),
+
+		// _ctypes appears to infer something from the linker name
+		"LDFLAGS=-Wl,--dynamic-linker=/system/lib/" +
+			"ld-musl-" + linuxArch() + ".so.1",
 	}, `
 # test_synopsis_sourceless assumes this is writable and checks __pycache__
 chmod -R +w /usr/src/python/

internal/rosa/rosa.go

@@ -65,10 +65,9 @@ const (
 	EnvTriplet = "ROSA_TRIPLE"
 )
 
-// ldflags returns LDFLAGS corresponding to triplet.
+// earlyLDFLAGS returns LDFLAGS corresponding to triplet.
-func ldflags(static bool) string {
+func earlyLDFLAGS(static bool) string {
-	s := "LDFLAGS=" +
+	s := "-fuse-ld=lld " +
-		"-fuse-ld=lld " +
 		"-L/system/lib -Wl,-rpath=/system/lib " +
 		"-L/system/lib/" + triplet() + " " +
 		"-Wl,-rpath=/system/lib/" + triplet() + " " +
@@ -76,7 +75,7 @@ func ldflags(static bool) string {
 		"-unwindlib=libunwind " +
 		"-Wl,--as-needed"
 	if !static {
-		s += " -Wl,--dynamic-linker=/system/lib/ld-musl-x86_64.so.1"
+		s += " -Wl,--dynamic-linker=/system/bin/linker"
 	}
 	return s
 }
@@ -199,7 +198,7 @@ ln -vs ../usr/bin /work/bin
 		env = fixupEnviron(env, []string{
 			EnvTriplet + "=" + triplet(),
 			lcMessages,
-			ldflags(true),
+			"LDFLAGS=" + earlyLDFLAGS(true),
 		}, "/system/bin",
 			"/usr/bin",
 			"/usr/lib/llvm/21/bin",
@@ -220,8 +219,6 @@ ln -vs ../usr/bin /work/bin
 			EnvTriplet + "=" + triplet(),
 			lcMessages,
 
-			ldflags(false),
-
 			"AR=ar",
 			"RANLIB=ranlib",
 			"LIBCC=/system/lib/clang/21/lib/" + triplet() +