Skip to content

[clr-interp] Fix GC liveness reporting stale data for a var, before it is actually set #128709

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
BrzVlad merged 2 commits into from
Jun 5, 2026
Merged

[clr-interp] Fix GC liveness reporting stale data for a var, before it is actually set #128709

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
88a2ab1
Print liveness ranges in hex offsets
BrzVlad May 28, 2026
4bdc501
[clr-interp] Fix GC liveness reporting stale data before instruction …
BrzVlad May 26, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 11 additions & 6 deletions src/coreclr/interpreter/compiler.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -883,7 +883,12 @@ int32_t InterpCompiler::GetLiveStartOffset(int32_t var)
else
{
assert(m_pVars[var].liveStart != NULL);
return m_pVars[var].liveStart->nativeOffset;
// The value of the var is not valid at the start of the instruction that sets it.
// We don't set it as the start of the next instruction because a live range needs
// to have start != end, which wouldn't be the case if the var is always dead. Ignoring
// the live range for such a var could be problematic if this var is the return of a call,
// with its address being passed directly to the a jit-ed method.
return m_pVars[var].liveStart->nativeOffset + GetInsLength(m_pVars[var].liveStart) - 1;
}
}

Expand Down Expand Up @@ -1399,16 +1404,16 @@ class InterpGcSlotAllocator
if (existingRange.OverlapsOrAdjacentTo(start, end))
{
ConservativeRange updatedRange = existingRange;
INTERP_DUMP("Merging with existing range [%u - %u]\n", existingRange.startOffset, existingRange.endOffset);
INTERP_DUMP("Merging with existing range [%04x - %04x]\n", existingRange.startOffset, existingRange.endOffset);
updatedRange.MergeWith(start, end);
while ((i + 1 < m_liveRanges.GetSize()) && m_liveRanges.Get(i + 1).OverlapsOrAdjacentTo(start, end))
{
ConservativeRange otherExistingRange = m_liveRanges.Get(i + 1);
INTERP_DUMP("Merging with existing range [%u - %u]\n", otherExistingRange.startOffset, otherExistingRange.endOffset);
INTERP_DUMP("Merging with existing range [%04x - %04x]\n", otherExistingRange.startOffset, otherExistingRange.endOffset);
updatedRange.MergeWith(otherExistingRange.startOffset, otherExistingRange.endOffset);
m_liveRanges.RemoveAt(i + 1);
}
INTERP_DUMP("Final merged range [%u - %u]\n", updatedRange.startOffset, updatedRange.endOffset);
INTERP_DUMP("Final merged range [%04x - %04x]\n", updatedRange.startOffset, updatedRange.endOffset);
m_liveRanges.Set(i, updatedRange);
return;
}
Expand Down Expand Up @@ -1497,7 +1502,7 @@ class InterpGcSlotAllocator
uint32_t startOffset = ConvertOffset(m_compiler->GetLiveStartOffset(varIndex)),
endOffset = ConvertOffset(m_compiler->GetLiveEndOffset(varIndex));
INTERP_DUMP(
"Slot %u (%s var #%d offset %u) live [IR_%04x - IR_%04x] [%u - %u]\n",
"Slot %u (%s var #%d offset %u) live [IR_%04x - IR_%04x] [%04x - %04x]\n",
slot, pVar->global ? "global" : "local",
varIndex, pVar->offset,
m_compiler->GetLiveStartOffset(varIndex), m_compiler->GetLiveEndOffset(varIndex),
Expand Down Expand Up @@ -1532,7 +1537,7 @@ class InterpGcSlotAllocator
ConservativeRange range = ranges->m_liveRanges.Get(iRange);

INTERP_DUMP(
"Conservative range for slot %u at %u [%u - %u]\n",
"Conservative range for slot %u at %u [%04x - %04x]\n",
*pSlot,
(unsigned)(iSlot * sizeof(void *)),
range.startOffset,
Expand Down
Loading