Mailing List Archive

Port configure script to C99
We are working to switch GCC to stricter defaults, catching up to C99
for a start. In support of that, we are trying to build Fedora with
such a compiler.

<https://fedoraproject.org/wiki/Changes/PortingToModernC>
<https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

We noticed that libgcrypt fails to build because it uses implicit
function declarations in the configure script. The patch below should
fix that.

Thanks,
Florian

diff --git a/configure.ac b/configure.ac
index 6ea38f53b8548ee8..2baf25bc7d9481e6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1211,7 +1211,8 @@ AC_CACHE_CHECK([.whether GCC assembler is compatible for ARM assembly implementat
/* Test if '.type' and '.size' are supported. */
".size asmfunc,.-asmfunc;\n\t"
".type asmfunc,%function;\n\t"
- );]], [ asmfunc(); ] )],
+ );
+ void asmfunc(void);]], [ asmfunc(); ] )],
[gcry_cv_gcc_arm_platform_as_ok=yes])
fi])
if test "$gcry_cv_gcc_arm_platform_as_ok" = "yes" ; then
@@ -1238,7 +1239,8 @@ AC_CACHE_CHECK([.whether GCC assembler is compatible for ARMv8/Aarch64 assembly i
"eor x0, x0, x30, ror #12;\n\t"
"add x0, x0, x30, asr #12;\n\t"
"eor v0.16b, v0.16b, v31.16b;\n\t"
- );]], [ asmfunc(); ] )],
+ );
+ void asmfunc(void);]], [ asmfunc(); ] )],
[gcry_cv_gcc_aarch64_platform_as_ok=yes])
fi])
if test "$gcry_cv_gcc_aarch64_platform_as_ok" = "yes" ; then
@@ -1267,7 +1269,8 @@ AC_CACHE_CHECK([whether GCC assembler supports for CFI directives],
".cfi_restore_state\n\t"
".long 0\n\t"
".cfi_endproc\n\t"
- );]])],
+ );
+ void asmfunc(void)]])],
[gcry_cv_gcc_asm_cfi_directives=yes])])
if test "$gcry_cv_gcc_asm_cfi_directives" = "yes" ; then
AC_DEFINE(HAVE_GCC_ASM_CFI_DIRECTIVES,1,
@@ -1666,7 +1669,8 @@ if test $amd64_as_feature_detection = yes; then
[gcry_cv_gcc_as_const_division_ok],
[gcry_cv_gcc_as_const_division_ok=no
AC_LINK_IFELSE([AC_LANG_PROGRAM(
- [[__asm__(".text\n\tfn:\n\t xorl \$(123456789/12345678), %ebp;\n\t");]],
+ [[__asm__(".text\n\tfn:\n\t xorl \$(123456789/12345678), %ebp;\n\t");
+ void fn(void);]],
[fn();])],
[gcry_cv_gcc_as_const_division_ok=yes])])
if test "$gcry_cv_gcc_as_const_division_ok" = "no" ; then
@@ -1679,7 +1683,8 @@ if test $amd64_as_feature_detection = yes; then
[gcry_cv_gcc_as_const_division_with_wadivide_ok],
[gcry_cv_gcc_as_const_division_with_wadivide_ok=no
AC_LINK_IFELSE([AC_LANG_PROGRAM(
- [[__asm__(".text\n\tfn:\n\t xorl \$(123456789/12345678), %ebp;\n\t");]],
+ [[__asm__(".text\n\tfn:\n\t xorl \$(123456789/12345678), %ebp;\n\t");
+ void fn(void);]],
[fn();])],
[gcry_cv_gcc_as_const_division_with_wadivide_ok=yes])])
if test "$gcry_cv_gcc_as_const_division_with_wadivide_ok" = "no" ; then
@@ -1715,7 +1720,8 @@ if test $amd64_as_feature_detection = yes; then
* and "-Wa,--divide" workaround failed, this causes assembly
* to be disable on this machine. */
"xorl \$(123456789/12345678), %ebp;\n\t"
- );]], [ asmfunc(); ])],
+ );
+ void asmfunc(void);]], [ asmfunc(); ])],
[gcry_cv_gcc_amd64_platform_as_ok=yes])
fi])
if test "$gcry_cv_gcc_amd64_platform_as_ok" = "yes" ; then
@@ -1734,7 +1740,8 @@ if test $amd64_as_feature_detection = yes; then
".globl asmfunc\n\t"
"asmfunc:\n\t"
"xorq \$(1234), %rbp;\n\t"
- );]], [ asmfunc(); ])],
+ );
+ void asmfunc(void);]], [ asmfunc(); ])],
[gcry_cv_gcc_win64_platform_as_ok=yes])])
if test "$gcry_cv_gcc_win64_platform_as_ok" = "yes" ; then
AC_DEFINE(HAVE_COMPATIBLE_GCC_WIN64_PLATFORM_AS,1,
@@ -1767,7 +1774,8 @@ AC_CACHE_CHECK([.whether GCC assembler is compatible for Intel syntax assembly im
"sub eax, [esp + 4];\n\t"
"add dword ptr [esp + eax], 0b10101;\n\t"
".att_syntax prefix\n\t"
- );]], [ actest(); ])],
+ );
+ void actest(void);]], [ actest(); ])],
[gcry_cv_gcc_platform_as_ok_for_intel_syntax=yes])
fi])
if test "$gcry_cv_gcc_platform_as_ok_for_intel_syntax" = "yes" ; then
@@ -1832,6 +1840,7 @@ AC_CACHE_CHECK([whether GCC inline assembler supports NEON instructions],
"vadd.u64 %q0, %q1;\n\t"
"vadd.s64 %d3, %d2, %d3;\n\t"
);
+ void testfn(void);
]], [ testfn(); ])],
[gcry_cv_gcc_inline_asm_neon=yes])
fi])
@@ -1879,6 +1888,7 @@ AC_CACHE_CHECK([.whether GCC inline assembler supports AArch32 Crypto Extension i

"vmull.p64 q0, d0, d0;\n\t"
);
+ void testfn(void);
]], [ testfn(); ])],
[gcry_cv_gcc_inline_asm_aarch32_crypto=yes])
fi])
@@ -1907,6 +1917,7 @@ AC_CACHE_CHECK([whether GCC inline assembler supports AArch64 NEON instructions]
"dup v0.8b, w0;\n\t"
"ld4 {v0.8b,v1.8b,v2.8b,v3.8b},[x0],\#32;\n\t"
);
+ void testfn(void);
]], [ testfn(); ])],
[gcry_cv_gcc_inline_asm_aarch64_neon=yes])
fi])
@@ -1955,6 +1966,7 @@ AC_CACHE_CHECK([.whether GCC inline assembler supports AArch64 Crypto Extension i
"pmull v0.1q, v0.1d, v31.1d;\n\t"
"pmull2 v0.1q, v0.2d, v31.2d;\n\t"
);
+ void testfn(void);
]], [ testfn(); ])],
[gcry_cv_gcc_inline_asm_aarch64_crypto=yes])
fi])
@@ -2050,6 +2062,7 @@ AC_CACHE_CHECK([.whether GCC inline assembler supports PowerPC AltiVec/VSX/crypto
"vshasigmad %v0, %v1, 0, 15;\n"
"vpmsumd %v11, %v11, %v11;\n"
);
+ void testfn(void);
]], [ testfn(); ] )],
[gcry_cv_gcc_inline_asm_ppc_altivec=yes])
fi])
@@ -2075,6 +2088,7 @@ AC_CACHE_CHECK([.whether GCC inline assembler supports PowerISA 3.00 instructions
"testfn:\n"
"stxvb16x %r1,%v12,%v30;\n"
);
+ void testfn(void);
]], [ testfn(); ])],
[gcry_cv_gcc_inline_asm_ppc_arch_3_00=yes])
fi])


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Re: Port configure script to C99 [ In reply to ]
Florian Weimer wrote:
> We noticed that libgcrypt fails to build because it uses implicit
> function declarations in the configure script. The patch below should
> fix that.

Thank you.

Applied and pushed the change (so that it has consistent tab&space) to
master. Will apply to 1.10 branch, too.

For libgcrypt, I found m4/ax_cc_for_build.m4 and m4/noexecstack.m4 have
similar problems. I'll fix.

For the source distribution (*.tar.bz2) which has generated configure
script, I think that we need to fix more. IIUC, Autoconf and Libtool
need to be updated.
--

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