[Git][ghc/ghc][wip/romes/remove-toolchain-runtime-config] Configure -Wl,--no-as-needed

[Rodrigo Mesquita (@alt-romes)]

Rodrigo Mesquita pushed to branch wip/romes/remove-toolchain-runtime-config at Glasgow Haskell Compiler / GHC


Commits:
53ea4e07 by Rodrigo Mesquita at 2023-06-26T15:59:51+01:00
Configure -Wl,--no-as-needed

To fixup, but this is one of the things we must now configure instead of
determine at runtime

Be sure to enumerate those in a bullet list

- - - - -


2 changed files:

- + m4/fp_link_supports_no_as_needed.m4
- m4/fptools_set_c_ld_flags.m4


Changes:

=====================================
m4/fp_link_supports_no_as_needed.m4
=====================================
@@ -0,0 +1,33 @@
+# FP_LINK_SUPPORTS_NO_AS_NEEDED
+# ----------------------------------
+# Set the Cc linker flag -Wl,--no-as-needed if it is supported
+# $1 is the name of the linker flags variable when linking with gcc
+# See also Note [ELF needed shared libs]
+AC_DEFUN([FP_LINK_SUPPORTS_NO_AS_NEEDED],
+[
+    AC_MSG_CHECKING([whether Cc linker supports -Wl,--no-as-needed])
+    echo 'int f(int a) {return 2*a;}' > conftest.a.c
+    echo 'int f(int a); int main(int argc, char **argv) {return f(0);}' > conftest.b.c
+    $CC -o conftest.a.o conftest.a.c
+    $CC -o conftest.b.o conftest.b.c
+    if "$CC" "$$1" -Wl,--no-as-needed -o conftest conftest.a.o conftest.b.o > /dev/null 2>&1
+    then
+        $1="$$1 -Wl,--no-as-needed"
+        AC_MSG_RESULT([yes])
+    else
+        AC_MSG_RESULT([no])
+    fi
+    rm -f conftest*
+])
+
+# Note [ELF needed shared libs]
+# ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+# Some distributions change the link editor's default handling of
+# ELF DT_NEEDED tags to include only those shared objects that are
+# needed to resolve undefined symbols. For Template Haskell we need
+# the last temporary shared library also if it is not needed for the
+# currently linked temporary shared library. We specify --no-as-needed
+# to override the default. This flag exists in GNU ld and GNU gold.
+# 
+# The flag is only needed on ELF systems. On Windows (PE) and Mac OS X
+# (Mach-O) the flag is not needed.


=====================================
m4/fptools_set_c_ld_flags.m4
=====================================
@@ -17,6 +17,13 @@ AC_DEFUN([FPTOOLS_SET_C_LD_FLAGS],
         ;;
     esac
 
+    # See Note [ELF needed shared libs]
+    case $$1 in
+    *-linux|*-freebsd*)
+        FP_LINK_SUPPORTS_NO_AS_NEEDED([$3])
+        ;;
+    esac
+
     case $$1 in
     i386-unknown-mingw32)
         $2="$$2 -march=i686"



View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/53ea4e07001bb6cc99c7360d91f05e07484b448b

-- 
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/53ea4e07001bb6cc99c7360d91f05e07484b448b
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