PR/56771 CVS commit: src/lib/libc/gmon

["Rin Okuyama" <rin%netbsd.org@localhost>]

The following reply was made to PR toolchain/56771; it has been noted by GNATS.

From: "Rin Okuyama" <rin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/56771 CVS commit: src/lib/libc/gmon
Date: Fri, 6 May 2022 04:49:13 +0000

 Module Name:	src
 Committed By:	rin
 Date:		Fri May  6 04:49:13 UTC 2022
 
 Modified Files:
 	src/lib/libc/gmon: gmon.c
 
 Log Message:
 PR lib/56395
 PR toolchain/56771
 
 Fix profiling on CPUs that do not support unaligned memory access;
 Allocate objects (referenced from struct gmonparam) with proper
 alignments.
 
 For monstartup(), objects are allocated on heap. Break is not
 guaranteed to be aligned at all, unlike stack pointer.
 
 For _m_gmon_alloc(), objects are allocated on anonymous memory.
 p->tos is not aligned properly in general.
 
 This fixes quasi-random crashes for *_profile tests, at least on
 SH-4 and PowerPC 403 [1]. Also, no regression is observed for
 others as far as I can see.
 
 This change does not cause any ABI breakage, as long as application
 uses proper pointers; use p->tos instead of evil pointer arithmetic
 like (struct tostruct *)((char *)p->froms + p->fromssize) [2].
 
 [1] Timeout should be increased for some tests. "pic" variants
 still fail as expected. Dynamically-linked binaries also crash in
 rtld for SH-4, but this seems different problem...
 
 [2] This example did not work even before, since the order of
 froms[] and tos[] is reversed depending on which of monstartup() or
 _m_gmon_alloc() is used for allocation.
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.36 -r1.37 src/lib/libc/gmon/gmon.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.