[flang] [clang] [flang][Driver] Support -nodefaultlibs, -nostartfiles and -nostdlib (PR #72601)

[Brad Smith via cfe-commits]

https://github.com/brad0 updated https://github.com/llvm/llvm-project/pull/72601

>From da17459071b039e9da0f53ae5e68ab1c3aaa13e4 Mon Sep 17 00:00:00 2001
From: Brad Smith <brad at comstyle.com>
Date: Wed, 15 Nov 2023 14:24:11 -0500
Subject: [PATCH] [flang][Driver] Support -nodefaultlibs, -nostartfiles and
 -nostdlib

---
 clang/include/clang/Driver/Options.td |  9 ++++---
 flang/test/Driver/dynamic-linker.f90  | 35 +++++++++++++++++++++++++++
 2 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index b2f2bcb6ac37910..bc04c53d7c76b9d 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5152,7 +5152,8 @@ def : Flag<["-"], "nocudalib">, Alias<nogpulib>;
 def gpulibc : Flag<["-"], "gpulibc">, Visibility<[ClangOption, CC1Option]>,
   HelpText<"Link the LLVM C Library for GPUs">;
 def nogpulibc : Flag<["-"], "nogpulibc">, Visibility<[ClangOption, CC1Option]>;
-def nodefaultlibs : Flag<["-"], "nodefaultlibs">;
+def nodefaultlibs : Flag<["-"], "nodefaultlibs">,
+  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>;
 def nodriverkitlib : Flag<["-"], "nodriverkitlib">;
 def nofixprebinding : Flag<["-"], "nofixprebinding">;
 def nolibc : Flag<["-"], "nolibc">;
@@ -5162,7 +5163,8 @@ def no_pie : Flag<["-"], "no-pie">, Visibility<[ClangOption, FlangOption]>;
 def noprebind : Flag<["-"], "noprebind">;
 def noprofilelib : Flag<["-"], "noprofilelib">;
 def noseglinkedit : Flag<["-"], "noseglinkedit">;
-def nostartfiles : Flag<["-"], "nostartfiles">, Group<Link_Group>;
+def nostartfiles : Flag<["-"], "nostartfiles">, Group<Link_Group>,
+  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>;
 def nostdinc : Flag<["-"], "nostdinc">,
   Visibility<[ClangOption, CLOption, DXCOption]>, Group<IncludePath_Group>;
 def nostdlibinc : Flag<["-"], "nostdlibinc">, Group<IncludePath_Group>;
@@ -5170,7 +5172,8 @@ def nostdincxx : Flag<["-"], "nostdinc++">, Visibility<[ClangOption, CC1Option]>
   Group<IncludePath_Group>,
   HelpText<"Disable standard #include directories for the C++ standard library">,
   MarshallingInfoNegativeFlag<HeaderSearchOpts<"UseStandardCXXIncludes">>;
-def nostdlib : Flag<["-"], "nostdlib">, Group<Link_Group>;
+def nostdlib : Flag<["-"], "nostdlib">, Group<Link_Group>,
+  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>;
 def nostdlibxx : Flag<["-"], "nostdlib++">;
 def object : Flag<["-"], "object">;
 def o : JoinedOrSeparate<["-"], "o">,
diff --git a/flang/test/Driver/dynamic-linker.f90 b/flang/test/Driver/dynamic-linker.f90
index df119c22a2ea516..aa90be5ac196e0e 100644
--- a/flang/test/Driver/dynamic-linker.f90
+++ b/flang/test/Driver/dynamic-linker.f90
@@ -18,3 +18,38 @@
 ! MSVC-LINKER-OPTIONS: "{{.*}}link{{(.exe)?}}"
 ! MSVC-LINKER-OPTIONS-SAME: "-dll"
 ! MSVC-LINKER-OPTIONS-SAME: "-rpath" "/path/to/dir"
+
+! Verify that certain linker flags are known to the frontend and are not passed on
+! to the linker.
+
+! RUN: %flang -### --target=x86_64-unknown-freebsd -nostdlib %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTDLIB %s
+! RUN: %flang -### --target=x86_64-unknown-netbsd -nostdlib %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTDLIB %s
+! RUN: %flang -### --target=i386-pc-solaris2.11 -nostdlib %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTDLIB %s
+
+! NOSTDLIB: "{{.*}}ld{{(.exe)?}}"
+! NOSTDLIB-NOT: crt{{[^.]+}}.o
+! NOSTDLIB-NOT: "-lFortran_main" "-lFortranRuntime" "-lFortranDecimal" "-lm"
+
+! RUN: %flang -### --target=x86_64-unknown-freebsd -nodefaultlibs %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NODEFAULTLIBS %s
+! RUN: %flang -### --target=x86_64-unknown-netbsd -nodefaultlibs %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NODEFAULTLIBS %s
+! RUN: %flang -### --target=i386-pc-solaris2.11 -nodefaultlibs %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NODEFAULTLIBS %s
+
+! NODEFAULTLIBS: "{{.*}}ld{{(.exe)?}}"
+! NODEFAULTLIBS-NOT: "-lFortran_main" "-lFortranRuntime" "-lFortranDecimal" "-lm"
+
+! RUN: %flang -### --target=x86_64-unknown-freebsd -nostartfiles %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTARTFILES %s
+! RUN: %flang -### --target=x86_64-unknown-netbsd -nostartfiles %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTARTFILES %s
+! RUN: %flang -### --target=i386-pc-solaris2.11 -nostartfiles %s 2>&1 | FileCheck \
+! RUN:     --check-prefixes=NOSTARTFILES %s
+
+! NOSTARTFILES: "{{.*}}ld{{(.exe)?}}"
+! NOSTARTFILES-NOT: crt{{[^.]+}}.o
+! NOSTARTFILES: "-lFortran_main" "-lFortranRuntime" "-lFortranDecimal" "-lm"