llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-driver Author: Louis Dionne (ldionne) <details> <summary>Changes</summary> When libc++ is bootstrapped with clang, the resulting clang uses the just-built libcxx headers from <install>/bin/../include/c++/v1. However, before this patch, clang would still use the system-provided libc++.dylib (usually in the Apple SDK) because it would fail to add the corresponding linker flag to find the just-built libc++. After this patch, Clang will also add `-L <install>/bin/../lib` to the linker search paths, which will allow the just-built libc++.dylib to be found. Fixes #<!-- -->77653 rdar://107060541 --- Full diff: https://github.com/llvm/llvm-project/pull/170303.diff 10 Files Affected: - (modified) clang/lib/Driver/ToolChains/Darwin.cpp (+41-3) - (added) clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++.dylib () - (added) clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++experimental.a () - (added) clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/bin/.keep () - (added) clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/include/c++/v1/.keep () - (added) clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++.a () - (added) clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++experimental.a () - (modified) clang/test/Driver/darwin-header-search-libcxx.cpp (+2-2) - (added) clang/test/Driver/darwin-link-libcxx.cpp (+81) - (modified) clang/test/Driver/experimental-library-flag.cpp (+5-3) ``````````diff diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp index fc3cd9030f71d..6665b54ca473d 100644 --- a/clang/lib/Driver/ToolChains/Darwin.cpp +++ b/clang/lib/Driver/ToolChains/Darwin.cpp @@ -2846,11 +2846,49 @@ void AppleMachO::AddCXXStdlibLibArgs(const ArgList &Args, CXXStdlibType Type = GetCXXStdlibType(Args); switch (Type) { - case ToolChain::CST_Libcxx: - CmdArgs.push_back("-lc++"); + case ToolChain::CST_Libcxx: { + // On Darwin, we prioritize a libc++ located in the toolchain to a libc++ + // located in the sysroot. Unlike the driver for most other platforms, on + // Darwin we do that by explicitly passing the library path to the linker + // to avoid having to add the toolchain's `lib/` directory to the linker + // search path, which would make other libraries findable as well. + // + // Prefering the toolchain library over the sysroot library matches the + // behavior we have for headers, where we prefer headers in the toolchain + // over headers in the sysroot if there are any. Note that it's important + // for the header search path behavior to match the link-time search path + // behavior to ensure that we link the program against a library that + // matches the headers that were used to compile it. + // + // Otherwise, we end up compiling against some set of headers and then + // linking against a different library (which, confusingly, shares the same + // name) which may have been configured with different options, be at a + // different version, etc. + SmallString<128> InstallLib = llvm::sys::path::parent_path(getDriver().Dir); + llvm::sys::path::append(InstallLib, "lib"); // <install>/bin/../lib + auto Link = [&](StringRef Library) { + SmallString<128> Shared(InstallLib); + llvm::sys::path::append(Shared, + SmallString<4>("lib") + Library + ".dylib"); + SmallString<128> Static(InstallLib); + llvm::sys::path::append(Static, SmallString<4>("lib") + Library + ".a"); + SmallString<32> Relative("-l"); + Relative += Library; + + if (getVFS().exists(Shared)) { + CmdArgs.push_back(Args.MakeArgString(Shared)); + } else if (getVFS().exists(Static)) { + CmdArgs.push_back(Args.MakeArgString(Static)); + } else { + CmdArgs.push_back(Args.MakeArgString(Relative)); + } + }; + + Link("c++"); if (Args.hasArg(options::OPT_fexperimental_library)) - CmdArgs.push_back("-lc++experimental"); + Link("c++experimental"); break; + } case ToolChain::CST_Libstdcxx: // Unfortunately, -lstdc++ doesn't always exist in the standard search path; diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++.dylib b/clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++.dylib new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++experimental.a b/clang/test/Driver/Inputs/basic_darwin_toolchain/usr/lib/libc++experimental.a new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/bin/.keep b/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/bin/.keep new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/include/c++/v1/.keep b/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/include/c++/v1/.keep new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++.a b/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++.a new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++experimental.a b/clang/test/Driver/Inputs/basic_darwin_toolchain_static/usr/lib/libc++experimental.a new file mode 100644 index 0000000000000..e69de29bb2d1d diff --git a/clang/test/Driver/darwin-header-search-libcxx.cpp b/clang/test/Driver/darwin-header-search-libcxx.cpp index cc8ec9ceb89b3..e8985a4e22b2f 100644 --- a/clang/test/Driver/darwin-header-search-libcxx.cpp +++ b/clang/test/Driver/darwin-header-search-libcxx.cpp @@ -92,7 +92,7 @@ // CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1: "-internal-isystem" "[[TOOLCHAIN]]/usr/bin/../include/c++/v1" // CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1-NOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1" -// Make sure that using -nostdinc, -nostdinc++ or -nostdlib will drop both the toolchain +// Make sure that using -nostdinc, -nostdinc++ or -nostdlibinc will drop both the toolchain // C++ include path and the sysroot one. // // RUN: %clang -### %s -fsyntax-only 2>&1 \ @@ -116,7 +116,7 @@ // RUN: -isysroot %S/Inputs/basic_darwin_sdk_usr_cxx_v1 \ // RUN: -stdlib=platform \ // RUN: -nostdinc++ \ -// RUN: | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_usr \ +// RUN: | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_usr_cxx_v1 \ // RUN: -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \ // RUN: --check-prefix=CHECK-LIBCXX-NOSTDINCXX %s // CHECK-LIBCXX-NOSTDINCXX: "-cc1" diff --git a/clang/test/Driver/darwin-link-libcxx.cpp b/clang/test/Driver/darwin-link-libcxx.cpp new file mode 100644 index 0000000000000..1c4f31b257512 --- /dev/null +++ b/clang/test/Driver/darwin-link-libcxx.cpp @@ -0,0 +1,81 @@ +// UNSUPPORTED: system-windows + +// Tests to check that we link against the toolchain-provided libc++ built library when it is provided. +// This is required to prefer the toolchain's libc++ over the system's libc++, which matches the behavior +// we have for header search paths. + +// When libc++.dylib is NOT in the toolchain, we should use -lc++ and fall back to the libc++ +// in the sysroot. +// +// (1) Without -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain_no_libcxx/usr/bin \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain_no_libcxx \ +// RUN: --check-prefix=CHECK-1 %s +// CHECK-1: "/usr/bin/ld" +// CHECK-1: "-lc++" +// CHECK-1-NOT: "[[TOOLCHAIN]]/usr/lib" +// +// (2) With -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain_no_libcxx/usr/bin \ +// RUN: -fexperimental-library \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain_no_libcxx \ +// RUN: --check-prefix=CHECK-2 %s +// CHECK-2: "/usr/bin/ld" +// CHECK-2: "-lc++" "-lc++experimental" +// CHECK-2-NOT: "[[TOOLCHAIN]]/usr/lib" + +// When we have libc++.dylib in the toolchain, it should be used over the one in the sysroot. +// There are a few cases worth testing. +// +// (1) Without -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain/usr/bin \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \ +// RUN: --check-prefix=CHECK-3 %s +// CHECK-3: "/usr/bin/ld" +// CHECK-3: "[[TOOLCHAIN]]/usr/lib/libc++.dylib" +// CHECK-3-NOT: "-lc++" +// +// (2) With -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain/usr/bin \ +// RUN: -fexperimental-library \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \ +// RUN: --check-prefix=CHECK-4 %s +// CHECK-4: "/usr/bin/ld" +// CHECK-4: "[[TOOLCHAIN]]/usr/lib/libc++.dylib" +// CHECK-4: "[[TOOLCHAIN]]/usr/lib/libc++experimental.a" +// CHECK-4-NOT: "-lc++" +// CHECK-4-NOT: "-lc++experimental" + +// When we have libc++.a in the toolchain instead of libc++.dylib, it should be +// used over the one in the sysroot. +// +// (1) Without -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain_static/usr/bin \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain_static \ +// RUN: --check-prefix=CHECK-5 %s +// CHECK-5: "/usr/bin/ld" +// CHECK-5: "[[TOOLCHAIN]]/usr/lib/libc++.a" +// CHECK-5-NOT: "-lc++" +// +// (2) With -fexperimental-library. +// RUN: %clangxx -### %s 2>&1 \ +// RUN: --target=x86_64-apple-darwin \ +// RUN: -ccc-install-dir %S/Inputs/basic_darwin_toolchain_static/usr/bin \ +// RUN: -fexperimental-library \ +// RUN: | FileCheck -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain_static \ +// RUN: --check-prefix=CHECK-6 %s +// CHECK-6: "/usr/bin/ld" +// CHECK-6: "[[TOOLCHAIN]]/usr/lib/libc++.a" +// CHECK-6: "[[TOOLCHAIN]]/usr/lib/libc++experimental.a" +// CHECK-6-NOT: "-lc++" +// CHECK-6-NOT: "-lc++experimental" diff --git a/clang/test/Driver/experimental-library-flag.cpp b/clang/test/Driver/experimental-library-flag.cpp index 62b007516897e..0546a09d5518b 100644 --- a/clang/test/Driver/experimental-library-flag.cpp +++ b/clang/test/Driver/experimental-library-flag.cpp @@ -18,6 +18,8 @@ // CHECK: -fexperimental-library // Depending on the stdlib in use, we should (or not) pass -lc++experimental. -// CHECK-LIBCXX: -lc++experimental -// CHECK-LIBSTDCXX-NOT: -lc++experimental -// CHECK-NOSTDLIB-NOT: -lc++experimental +// Note that we don't check for `-lc++experimental` specifically, since some targets +// like Darwin pass the path to the library explicitly instead of using `-lx`. +// CHECK-LIBCXX: c++experimental +// CHECK-LIBSTDCXX-NOT: c++experimental +// CHECK-NOSTDLIB-NOT: c++experimental `````````` </details> https://github.com/llvm/llvm-project/pull/170303 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
