49 lines
1.7 KiB
Text
49 lines
1.7 KiB
Text
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# asm-underscore.m4 serial 1
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dnl Copyright (C) 2010 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl From Bruno Haible. Based on as-underscore.m4 in GNU clisp.
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# gl_ASM_SYMBOL_PREFIX
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# Tests for the prefix of C symbols at the assembly language level and the
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# linker level. This prefix is either an underscore or empty. Defines the
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# C macro USER_LABEL_PREFIX to this prefix, and sets ASM_SYMBOL_PREFIX to
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# a stringified variant of this prefix.
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AC_DEFUN([gl_ASM_SYMBOL_PREFIX],
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[
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dnl We don't use GCC's __USER_LABEL_PREFIX__ here, because
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dnl 1. It works only for GCC.
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dnl 2. It is incorrectly defined on some platforms, in some GCC versions.
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AC_CACHE_CHECK(
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[whether C symbols are prefixed with underscore at the linker level],
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[gl_cv_prog_as_underscore],
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[cat > conftest.c <<EOF
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#ifdef __cplusplus
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extern "C" int foo (void);
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#endif
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int foo(void) { return 0; }
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EOF
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# Look for the assembly language name in the .s file.
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AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -S conftest.c) >/dev/null 2>&1
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if grep _foo conftest.s >/dev/null ; then
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gl_cv_prog_as_underscore=yes
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else
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gl_cv_prog_as_underscore=no
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fi
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rm -f conftest*
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])
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if test $gl_cv_prog_as_underscore = yes; then
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USER_LABEL_PREFIX=_
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else
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USER_LABEL_PREFIX=
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fi
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AC_DEFINE_UNQUOTED([USER_LABEL_PREFIX], [$USER_LABEL_PREFIX],
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[Define to the prefix of C symbols at the assembler and linker level,
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either an underscore or empty.])
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ASM_SYMBOL_PREFIX='"'${USER_LABEL_PREFIX}'"'
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AC_SUBST([ASM_SYMBOL_PREFIX])
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])
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