simple 64-bit fixes in Parser/ dir

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

BPO	400523
Nosy	@gvanrossum
Files	None: None

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields: ```python assignee = 'https://github.com/gvanrossum' closed_at = created_at = labels = [] title = 'simple 64-bit fixes in Parser/ dir' updated_at = user = 'https://bugs.python.org/tmick' ``` bugs.python.org fields: ```python activity = actor = 'tmick' assignee = 'gvanrossum' closed = True closed_date = None closer = None components = ['None'] creation = creator = 'tmick' dependencies = [] files = ['2453'] hgrepos = [] issue_num = 400523 keywords = ['patch'] message_count = 4.0 messages = ['32779', '32780', '32781', '32782'] nosy_count = 2.0 nosy_names = ['gvanrossum', 'tmick'] pr_nums = [] priority = 'normal' resolution = None stage = None status = 'closed' superseder = None type = None url = 'https://bugs.python.org/issue400523' versions = [] ```

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

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[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

This patch is one of a set of five (one per python/dist/src/* directory). They have been broken up to keep the patches small such that people might spend the time to review them. If one single patch would be prefered I can provide that.

This patch makes some simple changes for the benefit of 64-bit platforms (to avoid possible overflows where C data types have changed sizes and to eliminate unnecessary warnings). Each change fits into one of the following categories:

• Change a local variable declaration from int to size_t where appropriate. This is typically done for variables that hold strlen() or sizeof() results. On 64-bit platforms sizeof(int) \< sizeof(size_t), so using size_t avoids a downcast warning (or overflow). The variable is often later downcast to an int anyway but it is (IMO) more appropriate to do the downcast where the downcast is necessary and not before. 32-bit platforms are not affected by this change.
• Change (int) casts to (size_t) casts within comparisons where appropriate. This can avoid an unnecessary possible overflow (in somecases) and a warning on 64-bit platforms.
• Remove pointer downcasts to (long) for comparison (see Objects/object.c). This is unreliable on Win64 where sizeof(void*) > sizeof(long).
• Add a check for int overflow and raise and OverflowError where it cannot be proven a priori that int will not overflow. This is usually associated with string lengths. While it may seem overkill to have a check to ensure that a string does not overflow 2G characters it *is* a potential for silent overflow.
• [Python/thread_nt.c] Use %p instead of %ld printf formatter for debugging output to print a pointer. %ld results in data loss on Win64.

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

[Tim Peters]

[Trent Mick] > ... > On 64-bit platforms sizeof(int) \< sizeof(size_t), so > using size_t avoids a downcast warning (or overflow).

I suppose we should be more careful about explaining the need for these changes. For example, the claim above isn't true, as there are 64-bit platforms where sizeof(int) == sizeof(size_t) too (the Cray J90 is one such platform Python kind of \<wink> runs on today, and indeed even shorts are 64 bits on that one).

The problems here are that Python implicitly assumes sizeof(int) == sizeof(size_t), because at the time Python was written size_t didn't exist and the long K&R tradition preceding ANSI C was that strlen returned an int-sized thing and malloc took one. So they're all in the nature of cleaning up after the C committee a decade later \<wink>.