[FreeBSD] Support -stdlib=libstdc++ #126302

arichardson · 2025-02-07T20:14:37Z

The experimental-library-flag.cpp test was failing on FreeBSD builders,
which turned to be caused by missing support for -stdlib=libcstdc++ (and
just using a hardcoded libc++ in all cases).
Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class
and dealing with the FreeSBD < 14 profiling support as a special case.

While touching the test file also drop the unnecessary -o %t.o. This is
not needed since the RUN lines use -### and don't produce any output.

Created using spr 1.3.6-beta.1

llvmbot · 2025-02-07T20:15:15Z

@llvm/pr-subscribers-clang

Author: Alexander Richardson (arichardson)

Changes

The experimental-library-flag.cpp test was failing on FreeBSD builders,
which turned to be caused by missing support for -stdlib=libcstdc++ (and
just using a hardcoded libc++ in all cases).
Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class
and dealing with the FreeSBD < 14 profiling support as a special case.

Full diff: https://github.com/llvm/llvm-project/pull/126302.diff

3 Files Affected:

(modified) clang/lib/Driver/ToolChains/FreeBSD.cpp (+5-5)
(modified) clang/test/Driver/experimental-library-flag.cpp (+5)
(modified) clang/test/Driver/freebsd.cpp (+6-2)

diff --git a/clang/lib/Driver/ToolChains/FreeBSD.cpp b/clang/lib/Driver/ToolChains/FreeBSD.cpp
index a6d859f0ebfec23..bd6ab0f8aba5768 100644
--- a/clang/lib/Driver/ToolChains/FreeBSD.cpp
+++ b/clang/lib/Driver/ToolChains/FreeBSD.cpp
@@ -452,12 +452,12 @@ void FreeBSD::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
 
 void FreeBSD::AddCXXStdlibLibArgs(const ArgList &Args,
                                   ArgStringList &CmdArgs) const {
+  Generic_ELF::AddCXXStdlibLibArgs(Args, CmdArgs);
   unsigned Major = getTriple().getOSMajorVersion();
-  bool Profiling = Args.hasArg(options::OPT_pg) && Major != 0 && Major < 14;
-
-  CmdArgs.push_back(Profiling ? "-lc++_p" : "-lc++");
-  if (Args.hasArg(options::OPT_fexperimental_library))
-    CmdArgs.push_back("-lc++experimental");
+  bool SuffixedLib = Args.hasArg(options::OPT_pg) && Major != 0 && Major < 14;
+  if (SuffixedLib && GetCXXStdlibType(Args) == CST_Libcxx)
+    llvm::replace(CmdArgs, static_cast<const char *>("-lc++"),
+                  static_cast<const char *>("-lc++_p"));
 }
 
 void FreeBSD::AddCudaIncludeArgs(const ArgList &DriverArgs,
diff --git a/clang/test/Driver/experimental-library-flag.cpp b/clang/test/Driver/experimental-library-flag.cpp
index db6a90b50f2553c..62b007516897e4b 100644
--- a/clang/test/Driver/experimental-library-flag.cpp
+++ b/clang/test/Driver/experimental-library-flag.cpp
@@ -9,6 +9,11 @@
 // RUN: %clangxx -fexperimental-library -stdlib=libstdc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBSTDCXX %s
 // RUN: %clangxx -fexperimental-library -stdlib=libc++ -nostdlib++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-NOSTDLIB %s
 
+/// The FreeBSD driver did not support -stdlib=libstdc++ previously, check that it does the right thing here.
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBCXX %s
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libstdc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBSTDCXX %s
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libc++ -nostdlib++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-NOSTDLIB %s
+
 // -fexperimental-library must be passed to CC1.
 // CHECK: -fexperimental-library
 
diff --git a/clang/test/Driver/freebsd.cpp b/clang/test/Driver/freebsd.cpp
index dc8c98d3c3cb749..af6b873a387f13c 100644
--- a/clang/test/Driver/freebsd.cpp
+++ b/clang/test/Driver/freebsd.cpp
@@ -1,9 +1,13 @@
 // RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd -stdlib=platform 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
 // RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd10.0 -stdlib=platform 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-TEN %s
+// RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: %clangxx %s -### -o %t.o --target=amdf64-unknown-freebsd -stdlib=libc++ 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd -stdlib=libstdc++ 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-STDLIBCXX %s
 // CHECK-DEFAULT: "-lc++" "-lm"
-// CHECK-TEN: "-lc++" "-lm"
+// CHECK-STDLIBCXX: "-lstdc++" "-lm"
 
 // RUN: %clangxx %s -### -pg -o %t.o --target=amd64-unknown-freebsd -stdlib=platform 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-PG-DEFAULT %s

llvmbot · 2025-02-07T20:15:16Z

@llvm/pr-subscribers-clang-driver

Author: Alexander Richardson (arichardson)

Changes

The experimental-library-flag.cpp test was failing on FreeBSD builders,
which turned to be caused by missing support for -stdlib=libcstdc++ (and
just using a hardcoded libc++ in all cases).
Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class
and dealing with the FreeSBD < 14 profiling support as a special case.

Full diff: https://github.com/llvm/llvm-project/pull/126302.diff

3 Files Affected:

(modified) clang/lib/Driver/ToolChains/FreeBSD.cpp (+5-5)
(modified) clang/test/Driver/experimental-library-flag.cpp (+5)
(modified) clang/test/Driver/freebsd.cpp (+6-2)

diff --git a/clang/lib/Driver/ToolChains/FreeBSD.cpp b/clang/lib/Driver/ToolChains/FreeBSD.cpp
index a6d859f0ebfec23..bd6ab0f8aba5768 100644
--- a/clang/lib/Driver/ToolChains/FreeBSD.cpp
+++ b/clang/lib/Driver/ToolChains/FreeBSD.cpp
@@ -452,12 +452,12 @@ void FreeBSD::addLibCxxIncludePaths(const llvm::opt::ArgList &DriverArgs,
 
 void FreeBSD::AddCXXStdlibLibArgs(const ArgList &Args,
                                   ArgStringList &CmdArgs) const {
+  Generic_ELF::AddCXXStdlibLibArgs(Args, CmdArgs);
   unsigned Major = getTriple().getOSMajorVersion();
-  bool Profiling = Args.hasArg(options::OPT_pg) && Major != 0 && Major < 14;
-
-  CmdArgs.push_back(Profiling ? "-lc++_p" : "-lc++");
-  if (Args.hasArg(options::OPT_fexperimental_library))
-    CmdArgs.push_back("-lc++experimental");
+  bool SuffixedLib = Args.hasArg(options::OPT_pg) && Major != 0 && Major < 14;
+  if (SuffixedLib && GetCXXStdlibType(Args) == CST_Libcxx)
+    llvm::replace(CmdArgs, static_cast<const char *>("-lc++"),
+                  static_cast<const char *>("-lc++_p"));
 }
 
 void FreeBSD::AddCudaIncludeArgs(const ArgList &DriverArgs,
diff --git a/clang/test/Driver/experimental-library-flag.cpp b/clang/test/Driver/experimental-library-flag.cpp
index db6a90b50f2553c..62b007516897e4b 100644
--- a/clang/test/Driver/experimental-library-flag.cpp
+++ b/clang/test/Driver/experimental-library-flag.cpp
@@ -9,6 +9,11 @@
 // RUN: %clangxx -fexperimental-library -stdlib=libstdc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBSTDCXX %s
 // RUN: %clangxx -fexperimental-library -stdlib=libc++ -nostdlib++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-NOSTDLIB %s
 
+/// The FreeBSD driver did not support -stdlib=libstdc++ previously, check that it does the right thing here.
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBCXX %s
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libstdc++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-LIBSTDCXX %s
+// RUN: %clangxx --target=x86_64-unknown-freebsd -fexperimental-library -stdlib=libc++ -nostdlib++ -### %s 2>&1 | FileCheck --check-prefixes=CHECK,CHECK-NOSTDLIB %s
+
 // -fexperimental-library must be passed to CC1.
 // CHECK: -fexperimental-library
 
diff --git a/clang/test/Driver/freebsd.cpp b/clang/test/Driver/freebsd.cpp
index dc8c98d3c3cb749..af6b873a387f13c 100644
--- a/clang/test/Driver/freebsd.cpp
+++ b/clang/test/Driver/freebsd.cpp
@@ -1,9 +1,13 @@
 // RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd -stdlib=platform 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
 // RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd10.0 -stdlib=platform 2>&1 \
-// RUN:   | FileCheck --check-prefix=CHECK-TEN %s
+// RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: %clangxx %s -### -o %t.o --target=amdf64-unknown-freebsd -stdlib=libc++ 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-DEFAULT %s
+// RUN: %clangxx %s -### -o %t.o --target=amd64-unknown-freebsd -stdlib=libstdc++ 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-STDLIBCXX %s
 // CHECK-DEFAULT: "-lc++" "-lm"
-// CHECK-TEN: "-lc++" "-lm"
+// CHECK-STDLIBCXX: "-lstdc++" "-lm"
 
 // RUN: %clangxx %s -### -pg -o %t.o --target=amd64-unknown-freebsd -stdlib=platform 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-PG-DEFAULT %s

Created using spr 1.3.6-beta.1

clang/lib/Driver/ToolChains/FreeBSD.cpp

brad0 · 2025-02-10T09:12:06Z

It's not missing as in like someone forgot. It is intentional. Same goes for FreeBSD and OpenBSD's Drivers. The base OS uses libc++ and anything else is not supported.

arichardson · 2025-02-10T17:09:23Z

It's not missing as in like someone forgot. It is intentional. Same goes for FreeBSD and OpenBSD's Drivers. The base OS uses libc++ and anything else is not supported.

You can install it from ports though and it should be possible to use that?

arichardson · 2025-02-15T20:45:38Z

ping, is this ok to merge?

bsdjhb · 2025-02-15T21:05:13Z

It's not missing as in like someone forgot. It is intentional. Same goes for FreeBSD and OpenBSD's Drivers. The base OS uses libc++ and anything else is not supported.

You could use it with a libstdc++ from ports. GCC supports both variants for the same reason. FreeBSD's default GCC ports include libstdc++ which is used for 3rd party packages built with GCC instead of clang. I also suggested this approach to Alex for fixing the test failure. I'd really rather the option "work". I depend on the option working in the reverse when using GCC to build FreeBSD's base system (that is, -stdlib=c++). Someone using -stdlib=stdc++ should get what they have explicitly asked for.

MaskRay

code/test looks good for me as a driver maintainer. Needs a stamp from a FreeBSD reviewer.

clang/test/Driver/freebsd.cpp

Created using spr 1.3.6-beta.1

The experimental-library-flag.cpp test was failing on FreeBSD builders, which turned to be caused by missing support for -stdlib=libcstdc++ (and just using a hardcoded libc++ in all cases). Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class and dealing with the FreeSBD < 14 profiling support as a special case. While touching the test file also drop the unnecessary `-o %t.o`. This is not needed since the RUN lines use -### and don't produce any output. Reviewed By: DimitryAndric, MaskRay Pull Request: llvm/llvm-project#126302 (cherry picked from commit f75126eeabba13ce2aab53c2e4296fca12b9da0d)

The experimental-library-flag.cpp test was failing on FreeBSD builders, which turned to be caused by missing support for -stdlib=libcstdc++ (and just using a hardcoded libc++ in all cases). Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class and dealing with the FreeSBD < 14 profiling support as a special case. While touching the test file also drop the unnecessary `-o %t.o`. This is not needed since the RUN lines use -### and don't produce any output. Reviewed By: DimitryAndric, MaskRay Pull Request: llvm/llvm-project#126302

The experimental-library-flag.cpp test was failing on FreeBSD builders, which turned to be caused by missing support for -stdlib=libcstdc++ (and just using a hardcoded libc++ in all cases). Simplify FreeBSD::AddCXXStdlibLibArgs() by deferring to the parent class and dealing with the FreeSBD < 14 profiling support as a special case. While touching the test file also drop the unnecessary `-o %t.o`. This is not needed since the RUN lines use -### and don't produce any output. Reviewed By: DimitryAndric, MaskRay Pull Request: llvm/llvm-project#126302 (cherry picked from commit f75126eeabba13ce2aab53c2e4296fca12b9da0d)

[𝘀𝗽𝗿] initial version

6b89c65

Created using spr 1.3.6-beta.1

llvmbot added clang Clang issues not falling into any other category clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' labels Feb 7, 2025

arichardson requested review from emaste, bsdjhb, DimitryAndric and jrtc27 February 7, 2025 20:14

typo fix in RUN line

3041071

Created using spr 1.3.6-beta.1

arichardson commented Feb 7, 2025

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arichardson mentioned this pull request Feb 15, 2025

Default to v9 semantics in clang CTSRD-CHERI/llvm-project#757

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MaskRay approved these changes Feb 15, 2025

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DimitryAndric approved these changes Feb 16, 2025

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arichardson added 2 commits February 16, 2025 12:26

drop -o %t.o

191de34

Created using spr 1.3.6-beta.1

fix typo in RUN line

358235b

Created using spr 1.3.6-beta.1

arichardson merged commit f75126e into main Feb 16, 2025
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arichardson deleted the users/arichardson/spr/freebsd-support-stdliblibstdc branch February 16, 2025 20:32

arichardson mentioned this pull request Feb 16, 2025

[FreeBSD] Support -stdlib=libstdc++ CTSRD-CHERI/llvm-project#759

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[FreeBSD] Support -stdlib=libstdc++ #126302

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[FreeBSD] Support -stdlib=libstdc++ #126302

[FreeBSD] Support -stdlib=libstdc++ #126302

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