Re: [ANNOUNCEMENT] GDB 8.1 release branch created!

[Eli Zaretskii <eliz@gnu.org>]

> From: Joel Brobecker <brobecker@adacore.com>
> Date: Fri,  5 Jan 2018 08:18:05 +0400 (+04)
> 
> A quick message to announce that the GDB 8.1 branch has just been created.
> 
> The prerelease snapshots will be available at:
> 
>     ftp://sourceware.org/pub/gdb/snapshots/branch/gdb.tar.xz
>     ftp://sourceware.org/pub/gdb/snapshots/branch/gdb.tar.gz

I've built this pre-release with mingw.org's MinGW, and found a few
problems.

The most serious one is the following compilation error:

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -fno-strict-aliasing -DNDEBUG -fwrapv -c -o python/py-arch.o -MT python/py-arch.o -MMD -MP  -MF python/.deps/py-arch.Tpo python/py-arch.c
     In file included from d:\usr\lib\gcc\mingw32\6.3.0\include\c++\math.h:36:0,
		      from build-gnulib/import/math.h:27,
		      from d:/usr/Python26/include/pyport.h:235,
		      from d:/usr/Python26/include/Python.h:58,
		      from python/python-internal.h:94,
		      from python/py-arch.c:24:
     d:\usr\lib\gcc\mingw32\6.3.0\include\c++\cmath:1157:11: error: '::hypot' has not been declared
	using ::hypot;
		^~~~~
     Makefile:1618: recipe for target `python/py-arch.o' failed

Googling suggests the following solution; is it okay to push this
(with the necessary logs and after doing the "paperwork" required for
branch changes)?  Or does someone have better ideas?  (Does this work
in MinGW64?)

--- gdb/python/python-internal.h~0	2018-01-12 05:31:04.000000000 +0200
+++ gdb/python/python-internal.h	2018-01-16 08:56:10.717759900 +0200
@@ -85,6 +85,12 @@
 #define HAVE_SNPRINTF 1
 #endif
 
+/* Another kludge to avoid compilation errors because MinGW defines
+   'hypot' to '_hypot', but the C++ headers says "using ::hypot".  */
+#if defined(__MINGW32__) && defined(__cplusplus)
+# define _hypot hypot
+#endif
+
 /* Request clean size types from Python.  */
 #define PY_SSIZE_T_CLEAN
 

The other problems I saw are compilation warnings, see below.  Some of
them sound like GCC doesn't understand our TRY/CATCH blocks, but others
seem like real problems, at least from the POV of a naïve reader such
as myself.  I wonder how come others don't see these warnings, and why
weren't they fixed during development, when we use -Werror.  Here are
the warnings I saw:

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -c -o cli/cli-cmds.o -MT cli/cli-cmds.o -MMD -MP  -MF cli/.deps/cli-cmds.Tpo cli/cli-cmds.c
     cli/cli-cmds.c: In function 'void complete_command(const char*, int)':
     cli/cli-cmds.c:277:71: warning: 'word' may be used uninitialized in this function [-Wmaybe-uninitialized]
	  = tracker->build_completion_result (word, word - arg, strlen (arg));
									    ^
     cli/cli-cmds.c:277:71: warning: 'tracker' may be used uninitialized in this function [-Wmaybe-uninitialized]

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -c -o breakpoint.o -MT breakpoint.o -MMD -MP  -MF ./.deps/breakpoint.Tpo breakpoint.c
     breakpoint.c: In function 'void check_status_watchpoint(bpstat)':
     breakpoint.c:5079:4: warning: 'e' may be used uninitialized in this function [-Wmaybe-uninitialized]
	 switch (e)
	 ^~~~~~
     breakpoint.c:5056:20: note: 'e' was declared here
	 wp_check_result e;
                    ^

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -c -o infrun.o -MT infrun.o -MMD -MP  -MF ./.deps/infrun.Tpo infrun.c
     In file included from infrun.c:26:0:
     inferior.h: In function 'void handle_vfork_child_exec_or_exit(int)':
     inferior.h:537:39: warning: '*((void*)(& maybe_restore_inferior)+20).scoped_restore_current_inferior::m_saved_inf' may be used uninitialized in this function [-Wmaybe-uninitialized]
	{ set_current_inferior (m_saved_inf); }
					    ^
     infrun.c:927:6: note: '*((void*)(& maybe_restore_inferior)+20).scoped_restore_current_inferior::m_saved_inf' was declared here
	   maybe_restore_inferior;
	   ^~~~~~~~~~~~~~~~~~~~~~
     In file included from inferior.h:48:0,
		      from infrun.c:26:
     progspace.h:285:47: warning: '*((void*)(& maybe_restore_inferior)+16).scoped_restore_current_program_space::m_saved_pspace' may be used uninitialized in this function [-Wmaybe-uninitialized]
	{ set_current_program_space (m_saved_pspace); }
						    ^
     infrun.c:927:6: note: '*((void*)(& maybe_restore_inferior)+16).scoped_restore_current_program_space::m_saved_pspace' was declared here
	   maybe_restore_inferior;
	   ^~~~~~~~~~~~~~~~~~~~~~

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -c -o typeprint.o -MT typeprint.o -MMD -MP  -MF ./.deps/
     typeprint.Tpo typeprint.c
     typeprint.c: In function 'void whatis_exp(const char*, int)':
     typeprint.c:515:60: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
       real_type = value_rtti_type (val, &full, &top, &using_enc);
                                                            ^

     g++ -x c++  -O2 -gdwarf-4 -g3    -I. -I. -I./common -I./config  -DLOCALEDIR="\"d:/usr/share/locale\"" -DHAVE_CONFIG_H -I./../include/opcode -I./../opcodes/.. -I./../readline/..   -I../bfd -I./../bfd -I./../include -I../libdecnumber -I./../libdecnumber   -I./gnulib/import -Ibuild-gnulib/import   -DTUI=1   -Id:/usr/include -Id:/usr/include/guile/2.0 -Id:/usr/include   -Id:/usr/Python26/include -Id:/usr/Python26/include -Wall -Wpointer-arith -Wno-unused -Wunused-value -Wunused-function -Wno-switch -Wno-char-subscripts -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized -Wno-format  -c -o compile/compile.o -MT compile/compile.o -MMD -MP -MF compile/.deps/compile.Tpo compile/compile.c
     compile/compile.c: In function 'void eval_compile_command(command_line*, const char*, compile_i_scope_types, void*)':
     compile/compile.c:549:20: warning: 'triplet_rx' may be used uninitialized in this function [-Wmaybe-uninitialized]
	      argc, argv);
			 ^
     compile/compile.c:466:9: note: 'triplet_rx' was declared here
	char *triplet_rx;
	      ^~~~~~~~~~