ntp_compiler.m4 revision 275970 
1dnl ######################################################################
2dnl Common m4sh code for compiler stuff
3AC_DEFUN([NTP_COMPILER], [
4AC_REQUIRE([AC_PROG_CC_C89])
5
6CFLAGS_NTP=
7CPPFLAGS_NTP=
8LDADD_NTP=
9LDFLAGS_NTP=
10AC_SUBST([CFLAGS_NTP])
11AC_SUBST([CPPFLAGS_NTP])
12AC_SUBST([LDADD_NTP])
13AC_SUBST([LDFLAGS_NTP])
14
15case "$ac_cv_prog_cc_c89" in
16 no)
17    AC_MSG_WARN([ANSI C89/ISO C90 is the minimum to compile NTP]
18		[ version 4.2.5 and higher.])
19    ;;
20esac
21
22AC_CACHE_CHECK(
23    [if $CC can handle @%:@warning],
24    [ntp_cv_cpp_warning],
25    [AC_COMPILE_IFELSE(
26	[AC_LANG_PROGRAM([[]], [[#warning foo]])],
27	[ntp_cv_cpp_warning=yes],
28	[ntp_cv_cpp_warning=no]
29    )]
30)
31case "$ntp_cv_cpp_warning" in
32 no)
33    AC_DEFINE([NO_OPTION_NAME_WARNINGS], [1],
34	[Should we avoid @%:@warning on option name collisions?])
35esac
36
37AC_CACHE_CHECK(
38    [if $CC supports __attribute__((...))],
39    [ntp_cv_cc_attribute],
40    [AC_COMPILE_IFELSE(
41	[AC_LANG_PROGRAM(
42	    [[]],
43	    [[void foo(void) __attribute__((__noreturn__));]]
44	    )],
45	[ntp_cv_cc_attribute=yes],
46	[ntp_cv_cc_attribute=no]
47    )]
48)
49case "$ntp_cv_cc_attribute" in
50 yes)
51    AC_DEFINE([HAVE___ATTRIBUTE__], [],
52	[defined if C compiler supports __attribute__((...))])
53esac
54AH_VERBATIM(
55    [HAVE___ATTRIBUTE___VERBATIM],
56    [
57	/* define away __attribute__() if unsupported */
58	#ifndef HAVE___ATTRIBUTE__
59	# define __attribute__(x) /* empty */
60	#endif
61	#define ISC_PLATFORM_NORETURN_PRE
62	#define ISC_PLATFORM_NORETURN_POST __attribute__((__noreturn__))
63    ]
64)
65
66case "$GCC" in
67 yes)
68    SAVED_CFLAGS="$CFLAGS"
69    CFLAGS="$CFLAGS -Wstrict-overflow"
70    AC_CACHE_CHECK(
71	[if $CC can handle -Wstrict-overflow], 
72	[ntp_cv_gcc_Wstrict_overflow], 
73	[AC_COMPILE_IFELSE(
74	    [AC_LANG_PROGRAM([[]], [[]])],
75	    [ntp_cv_gcc_Wstrict_overflow=yes],
76	    [ntp_cv_gcc_Wstrict_overflow=no]
77	)	]
78    )
79    #
80    # $ntp_cv_gcc_Wstrict_overflow is tested later to add the 
81    # flag to CFLAGS.
82    #
83    CFLAGS="$SAVED_CFLAGS -Winit-self"
84    AC_CACHE_CHECK(
85	[if $CC can handle -Winit-self], 
86	[ntp_cv_gcc_Winit_self],
87	[
88	    AC_COMPILE_IFELSE(
89		[AC_LANG_PROGRAM([[]], [[]])],
90		[ntp_cv_gcc_Winit_self=yes],
91		[ntp_cv_gcc_Winit_self=no]
92	    )
93	]
94    )
95    CFLAGS="$SAVED_CFLAGS"
96    AS_UNSET([SAVED_CFLAGS])
97    #
98    # $ntp_cv_gcc_Winit_self is tested later to add the 
99    # flag to CFLAGS_NTP.
100    #
101    AC_CACHE_CHECK(
102	[if linker supports omitting unused code and data],
103	[ntp_cv_gc_sections_runs],
104	[
105	    dnl  NetBSD will link but likely not run with --gc-sections
106	    dnl  http://bugs.ntp.org/1844
107	    dnl  http://gnats.netbsd.org/40401
108	    dnl  --gc-sections causes attempt to load as linux elf, with
109	    dnl  wrong syscalls in place.  Test a little gauntlet of
110	    dnl  simple stdio read code checking for errors, expecting
111	    dnl  enough syscall differences that the NetBSD code will
112	    dnl  fail even with Linux emulation working as designed.
113	    dnl  A shorter test could be refined by someone with access
114	    dnl  to a NetBSD host with Linux emulation working.
115	    origCFLAGS="$CFLAGS"
116	    CFLAGS="$CFLAGS -Wl,--gc-sections"
117	    AC_LINK_IFELSE(
118		[AC_LANG_PROGRAM(
119		    [[
120			#include <stdlib.h>
121			#include <stdio.h>
122		    ]],
123		    [[
124			FILE *	fpC;
125			char	buf[32];
126			size_t	cch;
127			int	read_success_once;
128
129			fpC = fopen("conftest.c", "r");
130			if (NULL == fpC)
131				exit(1);
132			do {
133				cch = fread(buf, sizeof(buf), 1, fpC);
134				read_success_once |= (0 != cch);
135			} while (0 != cch);
136			if (!read_success_once)
137				exit(2);
138			if (!feof(fpC))
139				exit(3);
140			if (0 != fclose(fpC))
141				exit(4);
142
143			exit(EXIT_SUCCESS);
144		    ]]
145		)],
146		[
147		    if test "X$cross_compiling" = "Xyes" || grep gc-sections conftest.err ; then
148			ntp_cv_gc_sections_runs=no
149		    else
150			ntp_cv_gc_sections_runs=no
151			./conftest >/dev/null 2>&1 && ntp_cv_gc_sections_runs=yes
152		    fi
153		],
154		[ntp_cv_gc_sections_runs=no]
155	    )
156	    CFLAGS="$origCFLAGS"
157	    AS_UNSET([origCFLAGS])
158	]
159    )
160    case "$ntp_cv_gc_sections_runs" in
161     yes)
162	LDADD_LIBNTP="-Wl,--gc-sections"
163	CFLAGS_NTP="$CFLAGS_NTP -ffunction-sections -fdata-sections"
164	;;
165     no)
166	LDADD_LIBNTP=
167	;;
168    esac
169    CFLAGS_NTP="$CFLAGS_NTP -Wall"
170    CFLAGS_NTP="$CFLAGS_NTP -Wcast-align"
171    CFLAGS_NTP="$CFLAGS_NTP -Wcast-qual"
172    # CFLAGS_NTP="$CFLAGS_NTP -Wconversion"
173    # CFLAGS_NTP="$CFLAGS_NTP -Werror"
174    # CFLAGS_NTP="$CFLAGS_NTP -Wextra"
175    # CFLAGS_NTP="$CFLAGS_NTP -Wfloat-equal"
176    CFLAGS_NTP="$CFLAGS_NTP -Wmissing-prototypes"
177    CFLAGS_NTP="$CFLAGS_NTP -Wpointer-arith"
178    CFLAGS_NTP="$CFLAGS_NTP -Wshadow"
179    # CFLAGS_NTP="$CFLAGS_NTP -Wtraditional"
180    # CFLAGS_NTP="$CFLAGS_NTP -Wwrite-strings"
181    case "$ntp_cv_gcc_Winit_self" in
182     yes)
183	CFLAGS_NTP="$CFLAGS_NTP -Winit-self"
184    esac
185    case "$ntp_cv_gcc_Wstrict_overflow" in
186     yes)
187	CFLAGS_NTP="$CFLAGS_NTP -Wstrict-overflow"
188    esac
189    # -W[no-]strict-prototypes might be added by NTP_OPENSSL
190esac
191
192NTP_OS_CFLAGS
193
194])dnl
195dnl ======================================================================
196