Use gen-as-const.py to process .pysym files.

This patch eliminates the gen-py-const.awk variant of gen-as-const,
switching to use of gnu-as-const.py (with a new --python option) to
process .pysym files (i.e., to generate nptl_lock_constants.py), as
the syntax of those files is identical to that of .sym files.

Note that the generated nptl_lock_constants.py is *not* identical to
the version generated by the awk script.  Apart from the trivial
changes (comment referencing the new script, and output being sorted),
the constant FUTEX_WAITERS, PTHREAD_MUTEXATTR_FLAG_BITS,
PTHREAD_MUTEXATTR_FLAG_PSHARED and PTHREAD_MUTEX_PRIO_CEILING_MASK are
now output as positive rather than negative constants (on x86_64
anyway; maybe not necessarily on 32-bit systems):

< FUTEX_WAITERS = -2147483648
---
> FUTEX_WAITERS = 2147483648

< PTHREAD_MUTEXATTR_FLAG_BITS = -251662336
< PTHREAD_MUTEXATTR_FLAG_PSHARED = -2147483648
---
> PTHREAD_MUTEXATTR_FLAG_BITS = 4043304960
> PTHREAD_MUTEXATTR_FLAG_PSHARED = 2147483648

< PTHREAD_MUTEX_PRIO_CEILING_MASK = -524288
---
> PTHREAD_MUTEX_PRIO_CEILING_MASK = 4294443008

This is because gen-as-const has a cast of the constant value to long
int, which gen-py-const lacks.

I think the positive values are more logically correct, since the
constants in question are in fact unsigned in C.  But to reliably
produce gen-as-const.py output for constants that always (in C and
Python) reflects the signedness of values with the high bit of "long
int" set would mean more complicated logic needs to be used in
computing values.

The more correct positive values by themselves produce a failure of
nptl/test-mutexattr-printers, because masking with
~PTHREAD_MUTEXATTR_FLAG_BITS & ~PTHREAD_MUTEX_NO_ELISION_NP now leaves
a bit -1 << 32 in the Python value, resulting in a KeyError exception.
To avoid that, places masking with ~ of one of the constants in
question are changed to mask with 0xffffffff as well (this reflects
how ~ in Python applies to an infinite-precision integer whereas ~ in
C does not do any promotions beyond the width of int).

Tested for x86_64.

	* scripts/gen-as-const.py (main): Handle --python option.
	* scripts/gen-py-const.awk: Remove.
	* Makerules (py-const-script): Use gen-as-const.py.
	($(py-const)): Likewise.
	* nptl/nptl-printers.py (MutexPrinter.read_status_no_robust): Mask
	with 0xffffffff together with ~(PTHREAD_MUTEX_PRIO_CEILING_MASK).
	(MutexAttributesPrinter.read_values): Mask with 0xffffffff
	together with ~PTHREAD_MUTEXATTR_FLAG_BITS and
	~PTHREAD_MUTEX_NO_ELISION_NP.
	* manual/README.pretty-printers: Update reference to
	gen-py-const.awk.

1 files changed, 14 insertions, 30 deletions

diff --git a/Makerules b/Makerules
index 8e49a73342..8df0a25a3d 100644
--- a/Makerules
+++ b/Makerules
@@ -232,42 +232,26 @@ ifdef gen-py-const-headers
 py-const-files := $(patsubst %.pysym,%.py,$(gen-py-const-headers))
 py-const-dir := $(objpfx)
 py-const := $(addprefix $(py-const-dir),$(py-const-files))
-py-const-script := $(..)scripts/gen-py-const.awk
+py-const-script := $(..)scripts/gen-as-const.py
 
-# This is a hack we use to generate .py files with constants for Python
-# pretty printers.  It works the same way as gen-as-const.
-# See scripts/gen-py-const.awk for details on how the awk | gcc mechanism
-# works.
+# This is a hack we use to generate .py files with constants for
+# Python code.
 #
-# $@.tmp and $@.tmp2 are temporary files we use to store the partial contents
-# of the target file.  We do this instead of just writing on $@ because, if the
-# build process terminates prematurely, re-running Make wouldn't run this rule
-# since Make would see that the target file already exists (despite it being
-# incomplete).
+# $@.tmp is a temporary file we use to store the partial contents of
+# the target file.  We do this instead of just writing on $@ because,
+# if the build process terminates prematurely, re-running Make
+# wouldn't run this rule since Make would see that the target file
+# already exists (despite it being incomplete).
 #
-# The sed line replaces "@name@SOME_NAME@value@SOME_VALUE@" strings from the
-# output of 'gcc -S' with "SOME_NAME = SOME_VALUE" strings.
-# The '-n' option, combined with the '/p' command, makes sed output only the
-# modified lines instead of the whole input file.  The output is redirected
-# to a .py file; we'll import it in the pretty printers file to read
-# the constants generated by gen-py-const.awk.
-# The regex has two capturing groups, for SOME_NAME and SOME_VALUE
-# respectively.  Notice SOME_VALUE may be prepended by a special character,
-# depending on the assembly syntax (e.g. immediates are prefixed by a '$'
-# in AT&T x86, and by a '#' in ARM).  We discard it using a complemented set
-# before the second capturing group.
+# The output is redirected to a .py file; we'll import it in the main
+# Python code to read the constants generated by gen-as-const.py.
 $(py-const): $(py-const-dir)%.py: %.pysym $(py-const-script) \
 	     $(common-before-compile)
 	$(make-target-directory)
-	$(AWK) -f $(py-const-script) $< \
-	       | $(CC) -S -o $@.tmp $(CFLAGS) $(CPPFLAGS) -x c -
-	echo '# GENERATED FILE\n' > $@.tmp2
-	echo '# Constant definitions for pretty printers.' >> $@.tmp2
-	echo '# See gen-py-const.awk for details.\n' >> $@.tmp2
-	sed -n -r 's/^.*@name@([^@]+)@value@[^[:xdigit:]Xx-]*([[:xdigit:]Xx-]+)@.*/\1 = \2/p' \
-	    $@.tmp >> $@.tmp2
-	mv -f $@.tmp2 $@
-	rm -f $@.tmp
+	$(PYTHON) $(py-const-script) --python \
+		  --cc="$(CC) $(CFLAGS) $(CPPFLAGS)" $< \
+		  > $@.tmp
+	mv -f $@.tmp $@
 
 generated += $(py-const)
 endif  # gen-py-const-headers