krytarowski created this revision.
krytarowski added reviewers: joerg, mgorny, ruiu, MaskRay.
krytarowski added a project: lld.
Herald added subscribers: llvm-commits, cfe-commits, mstorsjo, fedor.sergeev,
aheejin, emaste, dschuff.
Herald added projects: clang, LLVM.
The NetBSD target wraps the default Linux/ELF target with OS
specific customization. It is implemented as a light netbsd::link()
module wrapper that mutates arguments in argv[] and calls
elf::link().
This flavor detects the native/current and target Triple based on
argv[0] parsing. This is prerequisite for cross-compilation, in
particular the NetBSD distribution is cross-built always.
The default configuration of the ELF target is tuned for Linux and
there is no way to costomize in-place for the NetBSD target in the
same way as FreeBSD/OpenBSD. FreeBSD whenever needed can check
emulation name ("*_fbsd") and OpenBSD calls its extensions
"PT_OPENBSD_*".
This distinct flavor is needed for NetBSD as:
- the linker MUST work in the standalone mode
- it must be useful with gcc/pcc/others out of the box
- clang NetBSD driver shall not hardcode LLD specific options
- the linker must have support for cross-building
- LLD shall be a drop-in replacement for (NetBSD-patched) GNU ld
There is no code-duplication between the NetBSD and ELF modules.
The NetBSD driver for debugging purposes prints the Target string
for the -v|-V|--version command line argument. There is no functional
or code maintenance change for other Operating Systems, especially
the ELF ones.
Equivalent customization is already done for the Darwin mode. For
instance there are hardcoded default search paths such as "/usr/lib"
and "/Library/Frameworks" in DarwinLdDriver.cpp. There is a prior
art with the MinGW target that similarly wraps coff:link().
This change is a starting point for development of NetBSD support
in LLD.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D70048
Files:
clang/lib/Driver/ToolChain.cpp
lld/CMakeLists.txt
lld/NetBSD/CMakeLists.txt
lld/NetBSD/Driver.cpp
lld/NetBSD/Options.td
lld/include/lld/Common/Driver.h
lld/tools/lld/CMakeLists.txt
lld/tools/lld/lld.cpp
Index: lld/tools/lld/lld.cpp
===================================================================
--- lld/tools/lld/lld.cpp
+++ lld/tools/lld/lld.cpp
@@ -10,12 +10,13 @@
// function is a thin wrapper which dispatches to the platform specific
// driver.
//
-// lld is a single executable that contains four different linkers for ELF,
-// COFF, WebAssembly and Mach-O. The main function dispatches according to
-// argv[0] (i.e. command name). The most common name for each target is shown
+// lld is a single executable that contains five different linkers for ELF,
+// NetBSD, COFF, WebAssembly and Mach-O. The main function dispatches according
+// to argv[0] (i.e. command name). The most common name for each target is shown
// below:
//
// - ld.lld: ELF (Unix)
+// - nb.lld: ELF (NetBSD)
// - ld64: Mach-O (macOS)
// - lld-link: COFF (Windows)
// - ld-wasm: WebAssembly
@@ -45,6 +46,7 @@
enum Flavor {
Invalid,
Gnu, // -flavor gnu
+ NetBSD, // -flavor netbsd
WinLink, // -flavor link
Darwin, // -flavor darwin
Wasm, // -flavor wasm
@@ -58,6 +60,7 @@
static Flavor getFlavor(StringRef s) {
return StringSwitch<Flavor>(s)
.CasesLower("ld", "ld.lld", "gnu", Gnu)
+ .CasesLower("nb.lld", "netbsd", NetBSD)
.CasesLower("wasm", "ld-wasm", Wasm)
.CaseLower("link", WinLink)
.CasesLower("ld64", "ld64.lld", "darwin", Darwin)
@@ -100,10 +103,15 @@
#endif
#if LLVM_ON_UNIX
- // Use GNU driver for "ld" on other Unix-like system.
- if (progname == "ld")
+ // Use GNU or NetBSD driver for "ld" on other Unix-like system.
+ if (progname == "ld") {
+#if defined(__NetBSD__)
+ return NetBSD;
+#else
return Gnu;
#endif
+ }
+#endif
// Progname may be something like "lld-gnu". Parse it.
SmallVector<StringRef, 3> v;
@@ -141,7 +149,7 @@
// and we use it to detect whether we are running tests or not.
static bool canExitEarly() { return StringRef(getenv("LLD_IN_TEST")) != "1"; }
-/// Universal linker main(). This linker emulates the gnu, darwin, or
+/// Universal linker main(). This linker emulates the gnu, netbsd, darwin, or
/// windows linker based on the argv[0] or -flavor option.
int main(int argc, const char **argv) {
InitLLVM x(argc, argv);
@@ -152,6 +160,8 @@
if (isPETarget(args))
return !mingw::link(args);
return !elf::link(args, canExitEarly());
+ case NetBSD:
+ return !netbsd::link(args, canExitEarly());
case WinLink:
return !coff::link(args, canExitEarly());
case Darwin:
@@ -160,7 +170,7 @@
return !wasm::link(args, canExitEarly());
default:
die("lld is a generic driver.\n"
- "Invoke ld.lld (Unix), ld64.lld (macOS), lld-link (Windows), wasm-ld"
- " (WebAssembly) instead");
+ "Invoke ld.lld (Unix), nb.lld (NetBSD), ld64.lld (macOS), lld-link "
+ "(Windows), wasm-ld (WebAssembly) instead");
}
}
Index: lld/tools/lld/CMakeLists.txt
===================================================================
--- lld/tools/lld/CMakeLists.txt
+++ lld/tools/lld/CMakeLists.txt
@@ -12,6 +12,7 @@
lldCOFF
lldDriver
lldELF
+ lldNetBSD
lldMinGW
lldWasm
)
@@ -20,7 +21,7 @@
RUNTIME DESTINATION bin)
if(NOT LLD_SYMLINKS_TO_CREATE)
- set(LLD_SYMLINKS_TO_CREATE lld-link ld.lld ld64.lld wasm-ld)
+ set(LLD_SYMLINKS_TO_CREATE lld-link ld.lld nb.lld ld64.lld wasm-ld)
endif()
foreach(link ${LLD_SYMLINKS_TO_CREATE})
Index: lld/include/lld/Common/Driver.h
===================================================================
--- lld/include/lld/Common/Driver.h
+++ lld/include/lld/Common/Driver.h
@@ -28,6 +28,11 @@
llvm::raw_ostream &diag = llvm::errs());
}
+namespace netbsd {
+bool link(llvm::ArrayRef<const char *> args, bool canExitEarly,
+ llvm::raw_ostream &diag = llvm::errs());
+}
+
namespace mach_o {
bool link(llvm::ArrayRef<const char *> args, bool canExitEarly,
llvm::raw_ostream &diag = llvm::errs());
Index: lld/NetBSD/Options.td
===================================================================
--- /dev/null
+++ lld/NetBSD/Options.td
@@ -0,0 +1,7 @@
+include "llvm/Option/OptParser.td"
+
+class F<string name>: Flag<["--", "-"], name>;
+
+def version: F<"version">, HelpText<"Display the version number and exit">;
+def v: Flag<["-"], "v">, HelpText<"Display the version number">;
+def: Flag<["-"], "V">, Alias<version>, HelpText<"Alias for --version">;
Index: lld/NetBSD/Driver.cpp
===================================================================
--- /dev/null
+++ lld/NetBSD/Driver.cpp
@@ -0,0 +1,187 @@
+//===- nb.lld.cpp - NetBSD LLD standalone linker --------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// The NetBSD flavor of LLD.
+//
+// This driver wraps the default ELF/GNU lld linker with NetBSD specific
+// customization.
+//
+// This code supports standalone linker usage.
+//
+//===----------------------------------------------------------------------===//
+
+#include "lld/Common/Driver.h"
+#include "lld/Common/ErrorHandler.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Option/Option.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+
+using namespace lld;
+using namespace llvm;
+using namespace llvm::sys;
+
+namespace {
+enum ID {
+ OPT_INVALID = 0, // This is not an option ID.
+#define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
+#include "Options.inc"
+#undef OPTION
+};
+
+#define PREFIX(NAME, VALUE) const char *const NAME[] = VALUE;
+#include "Options.inc"
+#undef PREFIX
+
+// Create table mapping all options defined in Options.td
+static const opt::OptTable::Info infoTable[] = {
+#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X7, X8, X9, X10, X11, X12) \
+ {X1, X2, X10, X11, OPT_##ID, opt::Option::KIND##Class, \
+ X9, X8, OPT_##GROUP, OPT_##ALIAS, X7, X12},
+#include "Options.inc"
+#undef OPTION
+};
+
+class NetBSDOptTable : public opt::OptTable {
+public:
+ NetBSDOptTable() : OptTable(infoTable) {}
+};
+} // namespace
+
+static Triple targetTriple;
+
+static void setTargetTriple(StringRef argv0, opt::InputArgList &args) {
+ std::string targetError;
+
+ // Firstly, try to get it from program name prefix
+ std::string ProgName = llvm::sys::path::stem(argv0);
+ size_t lastComponent = ProgName.rfind('-');
+ if (lastComponent != std::string::npos) {
+ std::string prefix = ProgName.substr(0, lastComponent);
+ if (llvm::TargetRegistry::lookupTarget(prefix, targetError)) {
+ targetTriple = llvm::Triple(prefix);
+ return;
+ }
+ }
+
+ // Secondly, use the default target triple
+ targetTriple = llvm::Triple(getDefaultTargetTriple());
+}
+
+static void prependTargetCustomization(std::vector<const char *> &args) {
+ // force-disable RO segment due to ld.elf_so limitations
+ args.push_back("--no-rosegment");
+
+ // force-disable superfluous RUNPATH
+ args.push_back("--disable-new-dtags");
+
+ // force-disable superfluous GNU stack
+ args.push_back("-znognustack");
+
+ // set default image base address
+ switch (targetTriple.getArch()) {
+ case llvm::Triple::aarch64:
+ case llvm::Triple::aarch64_be:
+ args.push_back("--image-base=0x200100000");
+ break;
+ default:
+ break;
+ }
+
+ // NetBSD driver relies on the linker knowing the default search paths.
+ // Please keep this in sync with clang/lib/Driver/ToolChains/NetBSD.cpp
+ // (NetBSD::NetBSD constructor)
+ switch (targetTriple.getArch()) {
+ case llvm::Triple::x86:
+ args.push_back("-L=/usr/lib/i386");
+ break;
+ case llvm::Triple::arm:
+ case llvm::Triple::armeb:
+ case llvm::Triple::thumb:
+ case llvm::Triple::thumbeb:
+ switch (targetTriple.getEnvironment()) {
+ case llvm::Triple::EABI:
+ case llvm::Triple::GNUEABI:
+ args.push_back("-L=/usr/lib/eabi");
+ break;
+ case llvm::Triple::EABIHF:
+ case llvm::Triple::GNUEABIHF:
+ args.push_back("-L=/usr/lib/eabihf");
+ break;
+ default:
+ args.push_back("-L=/usr/lib/oabi");
+ break;
+ }
+ break;
+#if 0 // TODO
+ case llvm::Triple::mips64:
+ case llvm::Triple::mips64el:
+ if (tools::mips::hasMipsAbiArg(Args, "o32")) {
+ args.push_back("-L=/usr/lib/o32");
+ } else if (tools::mips::hasMipsAbiArg(Args, "64")) {
+ args.push_back("-L=/usr/lib/64");
+ }
+ break;
+#endif
+ case llvm::Triple::ppc:
+ args.push_back("-L=/usr/lib/powerpc");
+ break;
+ case llvm::Triple::sparc:
+ args.push_back("-L=/usr/lib/sparc");
+ break;
+ default:
+ break;
+ }
+
+ args.push_back("-L=/usr/lib");
+}
+
+// Adapt command line arguments for NetBSD and then call elf::link.
+bool netbsd::link(ArrayRef<const char *> argsArr, bool canExitEarly,
+ raw_ostream &diag) {
+ bool printTarget = false;
+
+ NetBSDOptTable parser;
+ unsigned MAI;
+ unsigned MAC;
+ opt::InputArgList args = parser.ParseArgs(argsArr.slice(1), MAI, MAC);
+
+ // Append to -v or -version the target information from slld.
+ if (args.hasArg(OPT_v) || args.hasArg(OPT_version))
+ printTarget = true;
+
+ InitializeAllTargets();
+ setTargetTriple(argsArr[0], args);
+
+ if (!targetTriple.isOSNetBSD()) {
+ error("invalid NetBSD target: " + targetTriple.str());
+ return false;
+ }
+
+ // Construct new argv[] that is passed to elf::link().
+ // It will contain NetBSD specific customization.
+ std::vector<const char *> Argv;
+
+ // Pretend that we were executed as the GNU/ELF target.
+ Argv.push_back("ld.lld");
+
+ // Prepend original arguments with the target options.
+ prependTargetCustomization(Argv);
+
+ // Append original arguments, skipping the program name.
+ for (auto I = argsArr.begin() + 1, E = argsArr.end(); I != E; ++I)
+ Argv.push_back(*I);
+
+ if (printTarget)
+ message("Target: " + targetTriple.str());
+
+ return elf::link(Argv, canExitEarly, diag);
+}
Index: lld/NetBSD/CMakeLists.txt
===================================================================
--- /dev/null
+++ lld/NetBSD/CMakeLists.txt
@@ -0,0 +1,24 @@
+set(LLVM_TARGET_DEFINITIONS Options.td)
+tablegen(LLVM Options.inc -gen-opt-parser-defs)
+add_public_tablegen_target(NetBSDOptionsTableGen)
+
+if(NOT LLD_BUILT_STANDALONE)
+ set(tablegen_deps intrinsics_gen)
+endif()
+
+add_lld_library(lldNetBSD
+ Driver.cpp
+
+ LINK_COMPONENTS
+ Option
+ Support
+ Target
+
+ LINK_LIBS
+ lldELF
+ lldCommon
+
+ DEPENDS
+ NetBSDOptionsTableGen
+ ${tablegen_deps}
+)
Index: lld/CMakeLists.txt
===================================================================
--- lld/CMakeLists.txt
+++ lld/CMakeLists.txt
@@ -222,4 +222,5 @@
add_subdirectory(COFF)
add_subdirectory(ELF)
add_subdirectory(MinGW)
+add_subdirectory(NetBSD)
add_subdirectory(wasm)
Index: clang/lib/Driver/ToolChain.cpp
===================================================================
--- clang/lib/Driver/ToolChain.cpp
+++ clang/lib/Driver/ToolChain.cpp
@@ -534,6 +534,8 @@
llvm::SmallString<8> LinkerName;
if (Triple.isOSDarwin())
LinkerName.append("ld64.");
+ else if (Triple.isOSNetBSD())
+ LinkerName.append("nb.");
else
LinkerName.append("ld.");
LinkerName.append(UseLinker);
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