84 lines
2.7 KiB
Plaintext
84 lines
2.7 KiB
Plaintext
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# asm-underscore.m4 serial 5
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dnl Copyright (C) 2010-2022 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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AC_REQUIRE([AC_PROG_EGREP])
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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_REQUIRE([gl_C_ASM])
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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 $gl_c_asm_opt conftest.c) >/dev/null 2>&1
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if LC_ALL=C $EGREP '(^|[[^a-zA-Z0-9_]])_foo([[^a-zA-Z0-9_]]|$)' conftest.$gl_asmext >/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='"'${USER_LABEL_PREFIX}'"'
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AC_SUBST([ASM_SYMBOL_PREFIX])
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])
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# gl_C_ASM
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# Determines how to produce an assembly language file from C source code.
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# Sets the variables:
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# gl_asmext - the extension of assembly language output,
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# gl_c_asm_opt - the C compiler option that produces assembly language output.
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AC_DEFUN([gl_C_ASM],
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[
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AC_EGREP_CPP([MicrosoftCompiler],
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[
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#ifdef _MSC_VER
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MicrosoftCompiler
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#endif
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],
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[dnl Microsoft's 'cl' and 'clang-cl' produce an .asm file, whereas 'clang'
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dnl produces a .s file. Need to distinguish 'clang' and 'clang-cl'.
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rm -f conftest*
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echo 'int dummy;' > conftest.c
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AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS -c conftest.c) >/dev/null 2>&1
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if test -f conftest.o; then
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gl_asmext='s'
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gl_c_asm_opt='-S'
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else
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gl_asmext='asm'
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gl_c_asm_opt='-c -Fa'
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fi
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rm -f conftest*
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],
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[gl_asmext='s'
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gl_c_asm_opt='-S'
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])
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])
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