Change VG_(am_extend_map_client) as follows:
- Tighten up on asserts
- Simplify; as the function grows memory into a free segment, there
cannot possibly be any translations to be discarded. Free segments
do not have translations. sane_NSegment will make sure.
- Change the prototype to take in the start address of the mapping and
return a pointer to the resized segment. Previously, the code
ok = VG_(am_extend_map_client)( &d, old_seg, needL );
if (!ok)
goto eNOMEM;
VG_TRACK( new_mem_mmap, needA, needL,
old_seg->hasR, old_seg->hasW, old_seg->hasX,
was examining old_seg->hasR etc even though VG_(am_extend_map_client)
stated that *old_seg was invalid after the function returned.
That wasn't exactly a problem, but clearly looked wrong.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14963 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/coregrind/m_aspacemgr/aspacemgr-linux.c b/coregrind/m_aspacemgr/aspacemgr-linux.c
index 41fb3e4..32ac842 100644
--- a/coregrind/m_aspacemgr/aspacemgr-linux.c
+++ b/coregrind/m_aspacemgr/aspacemgr-linux.c
@@ -2892,38 +2892,38 @@
#if HAVE_MREMAP
-/* Let SEG be a client mapping (anonymous or file). This fn extends
- the mapping forwards only by DELTA bytes, and trashes whatever was
- in the new area. Fails if SEG is not a single client mapping or if
- the new area is not accessible to the client. Fails if DELTA is
- not page aligned. *seg is invalid after a successful return. If
- *need_discard is True after a successful return, the caller should
- immediately discard translations from the new area. */
-
-Bool VG_(am_extend_map_client)( /*OUT*/Bool* need_discard,
- const NSegment* seg, SizeT delta )
+/* This function grows a client mapping in place into an adjacent free segment.
+ ADDR is the client mapping's start address and DELTA, which must be page
+ aligned, is the growth amount. The function returns a pointer to the
+ resized segment. The function is used in support of mremap. */
+const NSegment *VG_(am_extend_map_client)( Addr addr, SizeT delta )
{
Addr xStart;
SysRes sres;
- NSegment seg_copy = *seg;
- SizeT seg_old_len = seg->end + 1 - seg->start;
if (0)
VG_(am_show_nsegments)(0, "VG_(am_extend_map_client) BEFORE");
- if (seg->kind != SkFileC && seg->kind != SkAnonC)
- return False;
+ /* Get the client segment */
+ Int ix = find_nsegment_idx(addr);
+ aspacem_assert(ix >= 0 && ix < nsegments_used);
- if (delta == 0 || !VG_IS_PAGE_ALIGNED(delta))
- return False;
+ NSegment *seg = nsegments + ix;
+
+ aspacem_assert(seg->kind == SkFileC || seg->kind == SkAnonC);
+ aspacem_assert(delta > 0 && VG_IS_PAGE_ALIGNED(delta)) ;
xStart = seg->end+1;
- if (xStart + delta < delta)
- return False;
+ aspacem_assert(xStart + delta >= delta); // no wrap-around
- if (!VG_(am_is_valid_for_client_or_free_or_resvn)( xStart, delta,
- VKI_PROT_NONE ))
- return False;
+ /* The segment following the client segment must be a free segment and
+ it must be large enough to cover the additional memory. */
+ NSegment *segf = seg + 1;
+ aspacem_assert(segf->kind == SkFree);
+ aspacem_assert(segf->start == xStart);
+ aspacem_assert(xStart + delta - 1 <= segf->end);
+
+ SizeT seg_old_len = seg->end + 1 - seg->start;
AM_SANITY_CHECK;
sres = ML_(am_do_extend_mapping_NO_NOTIFY)( seg->start,
@@ -2931,14 +2931,13 @@
seg_old_len + delta );
if (sr_isError(sres)) {
AM_SANITY_CHECK;
- return False;
+ return NULL;
} else {
/* the area must not have moved */
aspacem_assert(sr_Res(sres) == seg->start);
}
- *need_discard = any_Ts_in_range( seg_copy.end+1, delta );
-
+ NSegment seg_copy = *seg;
seg_copy.end += delta;
add_segment( &seg_copy );
@@ -2946,7 +2945,7 @@
VG_(am_show_nsegments)(0, "VG_(am_extend_map_client) AFTER");
AM_SANITY_CHECK;
- return True;
+ return nsegments + find_nsegment_idx(addr);
}
diff --git a/coregrind/m_syswrap/syswrap-generic.c b/coregrind/m_syswrap/syswrap-generic.c
index 42d134c..eaf29d0 100644
--- a/coregrind/m_syswrap/syswrap-generic.c
+++ b/coregrind/m_syswrap/syswrap-generic.c
@@ -435,14 +435,12 @@
ok = VG_(am_covered_by_single_free_segment) ( needA, needL );
}
if (ok && advised == needA) {
- ok = VG_(am_extend_map_client)( &d, old_seg, needL );
- if (ok) {
+ const NSegment *new_seg = VG_(am_extend_map_client)( old_addr, needL );
+ if (new_seg) {
VG_TRACK( new_mem_mmap, needA, needL,
- old_seg->hasR,
- old_seg->hasW, old_seg->hasX,
+ new_seg->hasR,
+ new_seg->hasW, new_seg->hasX,
0/*di_handle*/ );
- if (d)
- VG_(discard_translations)( needA, needL, "do_remap(3)" );
return VG_(mk_SysRes_Success)( old_addr );
}
}
@@ -490,14 +488,13 @@
}
if (!ok || advised != needA)
goto eNOMEM;
- ok = VG_(am_extend_map_client)( &d, old_seg, needL );
- if (!ok)
+ const NSegment *new_seg = VG_(am_extend_map_client)( old_addr, needL );
+ if (!new_seg)
goto eNOMEM;
VG_TRACK( new_mem_mmap, needA, needL,
- old_seg->hasR, old_seg->hasW, old_seg->hasX,
+ new_seg->hasR, new_seg->hasW, new_seg->hasX,
0/*di_handle*/ );
- if (d)
- VG_(discard_translations)( needA, needL, "do_remap(6)" );
+
return VG_(mk_SysRes_Success)( old_addr );
}
/*NOTREACHED*/ vg_assert(0);
diff --git a/coregrind/pub_core_aspacemgr.h b/coregrind/pub_core_aspacemgr.h
index 915c37a..7db4141 100644
--- a/coregrind/pub_core_aspacemgr.h
+++ b/coregrind/pub_core_aspacemgr.h
@@ -286,15 +286,11 @@
/* --- --- --- resizing/move a mapping --- --- --- */
-/* Let SEG be a client mapping (anonymous or file). This fn extends
- the mapping forwards only by DELTA bytes, and trashes whatever was
- in the new area. Fails if SEG is not a single client mapping or if
- the new area is not accessible to the client. Fails if DELTA is
- not page aligned. *seg is invalid after a successful return. If
- *need_discard is True after a successful return, the caller should
- immediately discard translations from the new area. */
-extern Bool VG_(am_extend_map_client)( /*OUT*/Bool* need_discard,
- const NSegment* seg, SizeT delta );
+/* This function grows a client mapping in place into an adjacent free segment.
+ ADDR is the client mapping's start address and DELTA, which must be page
+ aligned, is the growth amount. The function returns a pointer to the
+ resized segment. The function is used in support of mremap. */
+extern const NSegment *VG_(am_extend_map_client)( Addr addr, SizeT delta );
/* Remap the old address range to the new address range. Fails if any
parameter is not page aligned, if the either size is zero, if any
