Add pretty printers for the NPTL lock types

This patch adds pretty printers for the following NPTL types:

- pthread_mutex_t
- pthread_mutexattr_t
- pthread_cond_t
- pthread_condattr_t
- pthread_rwlock_t
- pthread_rwlockattr_t

To load the pretty printers into your gdb session, do the following:

python
import sys
sys.path.insert(0, '/path/to/glibc/build/nptl/pretty-printers')
end

source /path/to/glibc/source/pretty-printers/nptl-printers.py

You can check which printers are registered and enabled by issuing the
'info pretty-printer' gdb command. Printers should trigger automatically when
trying to print a variable of one of the types mentioned above.

The printers are architecture-independent, and were manually tested on both
the gdb CLI and Eclipse CDT.

In order to work, the printers need to know the values of various flags that
are scattered throughout pthread.h and pthreadP.h as enums and #defines. Since
replicating these constants in the printers file itself would create a
maintenance burden, I wrote a script called gen-py-const.awk that Makerules uses
to extract the constants. This script is pretty much the same as gen-as-const.awk,
except it doesn't cast the constant values to 'long' and is thorougly documented.
The constants need only to be enumerated in a .pysym file, which is then referenced
by a Make variable called gen-py-const-headers.

As for the install directory, I discussed this with Mike Frysinger and Siddhesh
Poyarekar, and we agreed that it can be handled in a separate patch, and it shouldn't
block merging of this one.

In addition, I've written a series of test cases for the pretty printers.
Each lock type (mutex, condvar and rwlock) has two test programs, one for itself
and other for its related 'attributes' object. Each test program in turn has a
PExpect-based Python script that drives gdb and compares its output to the
expected printer's. The tests run on the glibc host, which is assumed to have
both gdb and PExpect; if either is absent the tests will fail with code 77
(UNSUPPORTED). For cross-testing you should use cross-test-ssh.sh as test-wrapper.
I've tested the printers on both a native build and a cross build using a Beaglebone
Black, with the build system's filesystem shared with the board through NFS.

Finally, I've written a README that explains all this and more.

Hopefully this should be good to go in now. Thanks.

ChangeLog:

2016-07-04  Martin Galvan  <martin.galvan@tallertechnologies.com>

	* Makeconfig (build-hardcoded-path-in-tests): Set to 'yes' for shared builds
	if tests-need-hardcoded-path is defined.
	(all-subdirs): Add pretty-printers.
	* Makerules ($(py-const)): New rule.
	* Rules (others): Add $(py-const), if defined.
	* nptl/Makefile (gen-py-const-headers): Define.
	* nptl/nptl-printers.py: New file.
	* nptl/nptl_lock_constants.pysym: Likewise.
	* pretty-printers/Makefile: Likewise.
	* pretty-printers/README: Likewise.
	* pretty-printers/test-condvar-attributes.c: Likewise.
	* pretty-printers/test-condvar-attributes.p: Likewise.
	* pretty-printers/test-condvar-printer.c: Likewise.
	* pretty-printers/test-condvar-printer.py: Likewise.
	* pretty-printers/test-mutex-attributes.c: Likewise.
	* pretty-printers/test-mutex-attributes.py: Likewise.
	* pretty-printers/test-mutex-printer.c: Likewise.
	* pretty-printers/test-mutex-printer.py: Likewise.
	* pretty-printers/test-rwlock-attributes.c: Likewise.
	* pretty-printers/test-rwlock-attributes.py: Likewise.
	* pretty-printers/test-rwlock-printer.c: Likewise.
	* pretty-printers/test-rwlock-printer.py: Likewise.
	* pretty-printers/test_common.py: Likewise.
	* scripts/gen-py-const.awk: Likewise.

1 files changed, 13 insertions, 1 deletions

diff --git a/Makeconfig b/Makeconfig
index 03fd89c13e..58bd3b3a1c 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -472,6 +472,18 @@ else
 +link-tests = $(+link-static-tests)
 endif
 endif
+
+# Some modules may have test programs that must always link against the newly
+# built libraries instead of the installed ones.  Such modules must define
+# tests-need-hardcoded-path in their Makefile before including Makerules.
+# This will cause the test programs to be linked with -rpath instead of
+# -rpath-link, and their dynamic linker will be set to the built ld.so.
+ifeq (yes,$(build-shared))
+ifdef tests-need-hardcoded-path
+build-hardcoded-path-in-tests := yes
+endif
+endif
+
 ifeq (yes,$(build-shared))
 ifndef rtld-LDFLAGS
 rtld-LDFLAGS = -Wl,-dynamic-linker=$(rtlddir)/$(rtld-installed-name)
@@ -1097,7 +1109,7 @@ all-subdirs = csu assert ctype locale intl catgets math setjmp signal	    \
 	      grp pwd posix io termios resource misc socket sysvipc gmon    \
 	      gnulib iconv iconvdata wctype manual shadow gshadow po argp   \
 	      crypt localedata timezone rt conform debug mathvec	    \
-	      $(add-on-subdirs) dlfcn elf
+	      $(add-on-subdirs) dlfcn elf pretty-printers
 
 ifndef avoid-generated
 # sysd-sorted itself will contain rules making the sysd-sorted target