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[WebAssembly] Don't use default GetLinkerPath
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We can't (don't want to) honor the same set of "-fuse-ld" flags with
WebAssembly since the ELF linkers (ld.lld, ld.gnu, etc) don't work with
wasm object files.

Instead we implement our own linker finding logic, similar or other
non-ELF platforms like MSVC.

We've had a few issues with CLANG_DEFAULT_LINKER overriding the
WebAssembly linker which doesn't make sense since there is no generic
linker that can handle WebAssembly today.

Differential Revision: https://reviews.llvm.org/D59743

llvm-svn: 356953
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@sbc100
sbc100 committed Mar 25, 2019
1 parent bc97887 commit 4dcf3ac
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Showing 4 changed files with 31 additions and 9 deletions.
23 changes: 22 additions & 1 deletion clang/lib/Driver/ToolChains/WebAssembly.cpp
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Expand Up @@ -12,6 +12,8 @@
#include "clang/Driver/Driver.h"
#include "clang/Driver/DriverDiagnostic.h"
#include "clang/Driver/Options.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include "llvm/Option/ArgList.h"

using namespace clang::driver;
Expand All @@ -36,14 +38,33 @@ bool wasm::Linker::isLinkJob() const { return true; }

bool wasm::Linker::hasIntegratedCPP() const { return false; }

std::string wasm::Linker::getLinkerPath(const ArgList &Args) const {
const ToolChain &ToolChain = getToolChain();
if (const Arg* A = Args.getLastArg(options::OPT_fuse_ld_EQ)) {
StringRef UseLinker = A->getValue();
if (!UseLinker.empty()) {
if (llvm::sys::path::is_absolute(UseLinker) &&
llvm::sys::fs::can_execute(UseLinker))
return UseLinker;

// Accept 'lld', and 'ld' as aliases for the default linker
if (UseLinker != "lld" && UseLinker != "ld")
ToolChain.getDriver().Diag(diag::err_drv_invalid_linker_name)
<< A->getAsString(Args);
}
}

return ToolChain.getDefaultLinker();
}

void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output,
const InputInfoList &Inputs,
const ArgList &Args,
const char *LinkingOutput) const {

const ToolChain &ToolChain = getToolChain();
const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
const char *Linker = Args.MakeArgString(getLinkerPath(Args));
ArgStringList CmdArgs;

if (Args.hasArg(options::OPT_s))
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1 change: 1 addition & 0 deletions clang/lib/Driver/ToolChains/WebAssembly.h
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Expand Up @@ -23,6 +23,7 @@ class LLVM_LIBRARY_VISIBILITY Linker : public GnuTool {
explicit Linker(const ToolChain &TC);
bool isLinkJob() const override;
bool hasIntegratedCPP() const override;
std::string getLinkerPath(const llvm::opt::ArgList &Args) const;
void ConstructJob(Compilation &C, const JobAction &JA,
const InputInfo &Output, const InputInfoList &Inputs,
const llvm::opt::ArgList &TCArgs,
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8 changes: 4 additions & 4 deletions clang/test/Driver/wasm-toolchain.c
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Expand Up @@ -12,25 +12,25 @@

// A basic C link command-line with unknown OS.

// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo -fuse-ld=wasm-ld %s 2>&1 | FileCheck -check-prefix=LINK %s
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK %s
// LINK: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK: wasm-ld{{.*}}" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C link command-line with optimization with unknown OS.

// RUN: %clang -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo -fuse-ld=wasm-ld %s 2>&1 | FileCheck -check-prefix=LINK_OPT %s
// RUN: %clang -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK_OPT %s
// LINK_OPT: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_OPT: wasm-ld{{.*}}" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C link command-line with known OS.

// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo -fuse-ld=wasm-ld %s 2>&1 | FileCheck -check-prefix=LINK_KNOWN %s
// RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK_KNOWN %s
// LINK_KNOWN: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi-musl" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C link command-line with optimization with known OS.

// RUN: %clang -### -O2 -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo -fuse-ld=wasm-ld %s 2>&1 | FileCheck -check-prefix=LINK_OPT_KNOWN %s
// RUN: %clang -### -O2 -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo %s 2>&1 | FileCheck -check-prefix=LINK_OPT_KNOWN %s
// LINK_OPT_KNOWN: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_OPT_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi-musl" "crt1.o" "[[temp]]" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

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8 changes: 4 additions & 4 deletions clang/test/Driver/wasm-toolchain.cpp
View file
Expand Up @@ -12,25 +12,25 @@

// A basic C++ link command-line with unknown OS.

// RUN: %clangxx -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo -fuse-ld=wasm-ld --stdlib=c++ %s 2>&1 | FileCheck -check-prefix=LINK %s
// RUN: %clangxx -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo --stdlib=c++ %s 2>&1 | FileCheck -check-prefix=LINK %s
// LINK: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK: wasm-ld{{.*}}" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C++ link command-line with optimization with unknown OS.

// RUN: %clangxx -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s --stdlib=c++ -fuse-ld=wasm-ld 2>&1 | FileCheck -check-prefix=LINK_OPT %s
// RUN: %clangxx -### -O2 -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s --stdlib=c++ 2>&1 | FileCheck -check-prefix=LINK_OPT %s
// LINK_OPT: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_OPT: wasm-ld{{.*}}" "-L/foo/lib" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C++ link command-line with known OS.

// RUN: %clangxx -### -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo -fuse-ld=wasm-ld --stdlib=c++ %s 2>&1 | FileCheck -check-prefix=LINK_KNOWN %s
// RUN: %clangxx -### -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo --stdlib=c++ %s 2>&1 | FileCheck -check-prefix=LINK_KNOWN %s
// LINK_KNOWN: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi-musl" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

// A basic C++ link command-line with optimization with known OS.

// RUN: %clangxx -### -O2 -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo %s --stdlib=c++ -fuse-ld=wasm-ld 2>&1 | FileCheck -check-prefix=LINK_OPT_KNOWN %s
// RUN: %clangxx -### -O2 -no-canonical-prefixes -target wasm32-unknown-wasi-musl --sysroot=/foo %s --stdlib=c++ 2>&1 | FileCheck -check-prefix=LINK_OPT_KNOWN %s
// LINK_OPT_KNOWN: clang{{.*}}" "-cc1" {{.*}} "-o" "[[temp:[^"]*]]"
// LINK_OPT_KNOWN: wasm-ld{{.*}}" "-L/foo/lib/wasm32-wasi-musl" "crt1.o" "[[temp]]" "-lc++" "-lc++abi" "-lc" "{{.*[/\\]}}libclang_rt.builtins-wasm32.a" "-o" "a.out"

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