source/tests/memcheck/valgrind-suppressions.sh
#! /usr/bin/awk -f
# A script to extract the actual suppression info from the output of (for example) valgrind --leak-check=full --show-reachable=yes --error-limit=no --gen-suppressions=all ./minimal
# The desired bits are between ^{ and ^} (including the braces themselves).
# The combined output should either be appended to /usr/lib/valgrind/default.supp, or placed in a .supp of its own
# If the latter, either tell valgrind about it each time with --suppressions=<filename>, or add that line to ~/.valgrindrc

# NB This script uses the |& operator, which I believe is gawk-specific. In case of failure, check that you're using gawk rather than some other awk

# The script looks for suppressions. When it finds one it stores it temporarily in an array,
# and also feeds it line by line to the external app 'md5sum' which generates a unique checksum for it.
# The checksum is used as an index in a different array. If an item with that index already exists the suppression must be a duplicate and is discarded.

BEGIN { suppression=0; md5sum = "md5sum" }
	# If the line begins with '{', it's the start of a supression; so set the var and initialise things
	/^{/	{
					 suppression=1; i=0; next
				}
	# If the line begins with '}' its the end of a suppression
	/^}/	{
					if (suppression)
					 { suppression=0;
						close(md5sum, "to")		# We've finished sending data to md5sum, so close that part of the pipe
						ProcessInput()			# Do the slightly-complicated stuff in functions
						delete supparray		# We don't want subsequent suppressions to append to it!
					}
		}
	# Otherwise, it's a normal line. If we're inside a supression, store it, and pipe it to md5sum. Otherwise it's cruft, so ignore it
		{ if (suppression)
				{
						supparray[++i] = $0
						print |& md5sum
				}
		}

function ProcessInput()
{
		# Pipe the result from md5sum, then close it
		md5sum |& getline result
		close(md5sum)
		# gawk can't cope with enormous ints like $result would be, so stringify it first by prefixing a definite string
		resultstring = "prefix"result

		if (! (resultstring in chksum_array) )
			{ chksum_array[resultstring] = 0;	# This checksum hasn't been seen before, so add it to the array
				OutputSuppression()				# and output the contents of the suppression
			}
}

function OutputSuppression()
{
	# A suppression is surrounded by '{' and '}'. Its data was stored line by line in the array
	print "{"
	for (n=1; n <= i; ++n)
		{ print supparray[n] }
	print "}"
}
