| Message ID | 87mxgi5fch.fsf@kepler.schwinge.homeip.net |
|---|---|
| State | Superseded, archived |
| Headers | show |
On 07/13/2011 06:13 PM, Thomas Schwinge wrote: > Alternatively, gcc_GAS_CHECK_FEATURE could be changed to emit the > temporary file by using a shell here-doc, which is what AC_TRY_COMPILE is > doing, for example. Change instead echo ifelse(...) > conftest.s to AS_ECHO([m4_if(...)]) > conftest.s in gcc_GAS_CHECK_FEATURE. Paolo
diff --git a/gcc/configure.ac b/gcc/configure.ac index c2163bf..73f0209 100644 --- a/gcc/configure.ac +++ b/gcc/configure.ac @@ -2538,7 +2538,7 @@ __FRAME_BEGIN__: .LSCIE1: .4byte 0x0 .byte 0x1 - .ascii "z\0" + .asciz "z" .byte 0x1 .byte 0x78 .byte 0x1a
Hallo! Diffing the make log of a build of GCC with SHELL not explicitly set (thus /bin/sh, which is bash) and one with SHELL=/bin/dash, I found the following unexpected difference: -checking assembler for eh_frame optimization... yes +checking assembler for eh_frame optimization... buggy This is from gcc/configure; which invokes acinclude.m4:gcc_GAS_CHECK_FEATURE for the ``eh_frame optimization'' check. Latter case, gcc/config.log: configure:22282: checking assembler for eh_frame optimization configure:22327: /usr/bin/as --32 -o conftest.o conftest.s >&5 conftest.s: Assembler messages: conftest.s: Warning: end of file in string; '"' inserted conftest.s:13: Warning: unterminated string; newline inserted There, the following happens: $ sh # This is bash. sh-4.1$ echo '.ascii "z\0"' .ascii "z\0" This is what GCC expects. However, with dash: $ dash $ echo '.ascii "z\0"' .ascii "z The backslash escape and everything after is cut off. The test in gcc/configure.ac: gcc_GAS_CHECK_FEATURE(eh_frame optimization, gcc_cv_as_eh_frame, [elf,2,12,0],, [ .text [...] .byte 0x1 .ascii "z\0" .byte 0x1 [...] As quickly determined in #gcc with Ian's and Ismail's help, this is unportable usage of the echo builtin (and also at least questionable for /bin/echo), so I'm suggesting the following simple fix: gcc/ * configure.ac (eh_frame optimization): Avoid unportable shell feature. Alternatively, gcc_GAS_CHECK_FEATURE could be changed to emit the temporary file by using a shell here-doc, which is what AC_TRY_COMPILE is doing, for example. Grüße, Thomas