Skip to content

[scudo] Change CompactPtrT and CompactPtrScale to optional #90797

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
merged 1 commit into from
Jul 8, 2024
Merged

[scudo] Change CompactPtrT and CompactPtrScale to optional #90797

Changes from all commits
Commits
Show all changes
1 commit
Select commit
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
16 changes: 8 additions & 8 deletions compiler-rt/lib/scudo/standalone/allocator_config.def
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -56,16 +56,8 @@ BASE_OPTIONAL(const bool, MaySupportMemoryTagging, false)
// SizeClassMap to use with the Primary.
PRIMARY_REQUIRED_TYPE(SizeClassMap)

// Defines the type and scale of a compact pointer. A compact pointer can
// be understood as the offset of a pointer within the region it belongs
// to, in increments of a power-of-2 scale. See `CompactPtrScale` also.
PRIMARY_REQUIRED_TYPE(CompactPtrT)

// PRIMARY_REQUIRED(TYPE, NAME)
//
// The scale of a compact pointer. E.g., Ptr = Base + (CompactPtr << Scale).
PRIMARY_REQUIRED(const uptr, CompactPtrScale)

// Log2 of the size of a size class region, as used by the Primary.
PRIMARY_REQUIRED(const uptr, RegionSizeLog)

Expand All @@ -86,6 +78,9 @@ PRIMARY_REQUIRED(const s32, MaxReleaseToOsIntervalMs)

// PRIMARY_OPTIONAL(TYPE, NAME, DEFAULT)
//
// The scale of a compact pointer. E.g., Ptr = Base + (CompactPtr << Scale).
PRIMARY_OPTIONAL(const uptr, CompactPtrScale, SCUDO_MIN_ALIGNMENT_LOG)

// Indicates support for offsetting the start of a region by a random number of
// pages. This is only used if `EnableContiguousRegions` is enabled.
PRIMARY_OPTIONAL(const bool, EnableRandomOffset, false)
Expand All @@ -104,6 +99,11 @@ PRIMARY_OPTIONAL(const bool, EnableContiguousRegions, true)
// guarantee a performance benefit.
PRIMARY_OPTIONAL_TYPE(ConditionVariableT, ConditionVariableDummy)

// Defines the type and scale of a compact pointer. A compact pointer can
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Defines ... and scale -> the scale is actually defined by CompactPtrScale

I think it might help here to document how to choose the proper type, for instance

This type is used to efficiently store arrays of pointers to free blocks, and it must be large enough to express offsets within an entire region, i.e. this type's maximum possible value must uphold MaxCompactPtrValue << CompactPtrScale >= 1 << RegionSizeLog. The default type (uptr) trivially satisfies this requirement but, depending on CompactPtrScale and RegionSizeLog, a smaller type could work too.

// be understood as the offset of a pointer within the region it belongs
// to, in increments of a power-of-2 scale. See `CompactPtrScale` also.
PRIMARY_OPTIONAL_TYPE(CompactPtrT, uptr)

// SECONDARY_REQUIRED_TEMPLATE_TYPE(NAME)
//
// Defines the type of Secondary Cache to use.
Expand Down
Loading