[clang] [clang] Add option for -nolibc in Driver/ToolChains/Baremetal.cpp (PR #145700)
William Huynh via cfe-commits
cfe-commits at lists.llvm.org
Thu Jul 3 02:10:27 PDT 2025
https://github.com/saturn691 updated https://github.com/llvm/llvm-project/pull/145700
>From 97c87ceb781eee0a04bd93299a341e03cbe68ddd Mon Sep 17 00:00:00 2001
From: William Huynh <William.Huynh at arm.com>
Date: Wed, 25 Jun 2025 14:25:22 +0100
Subject: [PATCH 1/5] [clang] Add option for -nolibc in
Driver/ToolChains/Baremetal.cpp
Some tests in LLVM-libc require this flag, so compiler-rt is still
linked in, but not the C library. With this change, it will not be
ignored.
Minor changes: clang-format
---
clang/lib/Driver/ToolChains/BareMetal.cpp | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index d8168ed15febd..b87427110d7de 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -339,15 +339,15 @@ void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
};
switch (GetCXXStdlibType(DriverArgs)) {
- case ToolChain::CST_Libcxx: {
- SmallString<128> P(D.Dir);
- llvm::sys::path::append(P, "..", "include");
- AddCXXIncludePath(P);
- break;
- }
- case ToolChain::CST_Libstdcxx:
- // We only support libc++ toolchain installation.
- break;
+ case ToolChain::CST_Libcxx: {
+ SmallString<128> P(D.Dir);
+ llvm::sys::path::append(P, "..", "include");
+ AddCXXIncludePath(P);
+ break;
+ }
+ case ToolChain::CST_Libstdcxx:
+ // We only support libc++ toolchain installation.
+ break;
}
std::string SysRoot(computeSysRoot());
@@ -498,7 +498,9 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
AddRunTimeLibs(TC, D, CmdArgs, Args);
- CmdArgs.push_back("-lc");
+ if (!Args.hasArg(options::OPT_nolibc)) {
+ CmdArgs.push_back("-lc");
+ }
}
if (D.isUsingLTO())
>From a433cb779d5b49baba32bae1ce63f151b5cea423 Mon Sep 17 00:00:00 2001
From: William Huynh <William.Huynh at arm.com>
Date: Thu, 26 Jun 2025 10:19:16 +0100
Subject: [PATCH 2/5] Add lit tests in clang/test/Driver/baremetal.cpp
---
clang/test/Driver/baremetal.cpp | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index a80aa9b437117..6dd1ec13d689b 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -143,6 +143,20 @@
// RUN: | FileCheck %s --check-prefix=CHECK-RTLIB-GCC
// CHECK-RTLIB-GCC: -lgcc
+// RUN: %clang -### --target=arm-none-eabi -nolibc %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix=CHECK-NOLIBC
+// CHECK-NOLIBC-NOT: "-lc"
+// CHECK-NOLIBC-NOT: "-lm"
+// CHECK-NOLIBC-NOT: "-lc++"
+// CHECK-NOLIBC: "{{[^"]*}}libclang_rt.builtins.a"
+
+// RUN: %clang -### --target=arm-none-eabi -nostdlib %s 2>&1 \
+// RUN: | FileCheck %s --check-prefix=CHECK-NOSTDLIB
+// CHECK-NOSTDLIB-NOT: "-lc"
+// CHECK-NOSTDLIB-NOT: "-lm"
+// CHECK-NOSTDLIB-NOT: "-lc++"
+// CHECK-NOSTDLIB-NOT: "{{[^"]*}}libclang_rt.builtins.a"
+
// RUN: %clang -### --target=arm-none-eabi -v %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-SYSROOT-INC
// CHECK-SYSROOT-INC-NOT: "-internal-isystem" "include"
>From 36f933f4b53b730afd0458d31a31eec4c3682ec1 Mon Sep 17 00:00:00 2001
From: William Huynh <William.Huynh at arm.com>
Date: Wed, 2 Jul 2025 11:49:22 +0100
Subject: [PATCH 3/5] Reapply suggestions from Petr
---
clang/test/Driver/baremetal.cpp | 4 ----
1 file changed, 4 deletions(-)
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index 471854aaa7b4b..7b78d71ad5de0 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -166,15 +166,11 @@
// RUN: %clang -### --target=arm-none-eabi -nolibc %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-NOLIBC
// CHECK-NOLIBC-NOT: "-lc"
-// CHECK-NOLIBC-NOT: "-lm"
-// CHECK-NOLIBC-NOT: "-lc++"
// CHECK-NOLIBC: "{{[^"]*}}libclang_rt.builtins.a"
// RUN: %clang -### --target=arm-none-eabi -nostdlib %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-NOSTDLIB
// CHECK-NOSTDLIB-NOT: "-lc"
-// CHECK-NOSTDLIB-NOT: "-lm"
-// CHECK-NOSTDLIB-NOT: "-lc++"
// CHECK-NOSTDLIB-NOT: "{{[^"]*}}libclang_rt.builtins.a"
// RUN: %clang -### --target=arm-none-eabi -v %s 2>&1 \
>From f4170d8b2c0cdf8c987ff5835070fd14acecec8a Mon Sep 17 00:00:00 2001
From: William Huynh <William.Huynh at arm.com>
Date: Wed, 2 Jul 2025 11:50:24 +0100
Subject: [PATCH 4/5] Delete trivial brace
---
clang/lib/Driver/ToolChains/BareMetal.cpp | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/BareMetal.cpp b/clang/lib/Driver/ToolChains/BareMetal.cpp
index dce3248b7587e..9145e8f5d5343 100644
--- a/clang/lib/Driver/ToolChains/BareMetal.cpp
+++ b/clang/lib/Driver/ToolChains/BareMetal.cpp
@@ -674,9 +674,8 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
CmdArgs.push_back("--start-group");
AddRunTimeLibs(TC, D, CmdArgs, Args);
- if (!Args.hasArg(options::OPT_nolibc)) {
+ if (!Args.hasArg(options::OPT_nolibc))
CmdArgs.push_back("-lc");
- }
if (TC.hasValidGCCInstallation() || detectGCCToolchainAdjacent(D))
CmdArgs.push_back("-lgloss");
CmdArgs.push_back("--end-group");
>From 68b2eda3762c60f1c0d2af118b2a13fae4fc951f Mon Sep 17 00:00:00 2001
From: William Huynh <William.Huynh at arm.com>
Date: Thu, 3 Jul 2025 10:10:13 +0100
Subject: [PATCH 5/5] Add -rtlib=compiler-rt to tests in baremetal.cpp
---
clang/test/Driver/baremetal.cpp | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/clang/test/Driver/baremetal.cpp b/clang/test/Driver/baremetal.cpp
index 7b78d71ad5de0..5c86cac4d3f3c 100644
--- a/clang/test/Driver/baremetal.cpp
+++ b/clang/test/Driver/baremetal.cpp
@@ -163,12 +163,12 @@
// RUN: | FileCheck %s --check-prefix=CHECK-RTLIB-GCC
// CHECK-RTLIB-GCC: -lgcc
-// RUN: %clang -### --target=arm-none-eabi -nolibc %s 2>&1 \
+// RUN: %clang -### --target=arm-none-eabi -nolibc -rtlib=compiler-rt %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-NOLIBC
// CHECK-NOLIBC-NOT: "-lc"
// CHECK-NOLIBC: "{{[^"]*}}libclang_rt.builtins.a"
-// RUN: %clang -### --target=arm-none-eabi -nostdlib %s 2>&1 \
+// RUN: %clang -### --target=arm-none-eabi -nostdlib -rtlib=compiler-rt %s 2>&1 \
// RUN: | FileCheck %s --check-prefix=CHECK-NOSTDLIB
// CHECK-NOSTDLIB-NOT: "-lc"
// CHECK-NOSTDLIB-NOT: "{{[^"]*}}libclang_rt.builtins.a"
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