To do this, BitsContainer is changed to be a more rope-like
representation of section portions. In addition to containing
most of the same information stored per-section previously, each
portion also has a section-relative offset that is calculated when
it is added. Thus, merging two compatible BitsContainer sections
is just adding the portions from the second to the first, tweaking
the section-relative offset for each.
Other changes in this CL:
* Create PseudoSections subclasses for the elf header, program
header table, and section header table, so we can treat them
more uniformly with the other parts of the ELF snapshot.
* We now only allocate as much BSS space in the snapshot as is needed
for any text sections in the snapshot, instead of always allocating
a big enough BSS space for both VM and isolate, even for deferred
snapshots where there is no VM isolate.
* We already separated segment and section alignment in previous CLs,
so the fact that our own ELF loader needs load segments to be
page-aligned no longer means that the sections within those segments
also needs to be. Thus, we align individual instructions sections to
kMaxObjectAlignment, like readonly data sections, since both hold a
single Image object. This removes unnecessary intra-section padding.
TEST=Tests that check DWARF information and trybots that use ELF
snapshots.
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-dwarf-linux-product-x64-try
Change-Id: If0315c8b7b0f31481b676a8901f49cd3a44b5561
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/206365
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
This relands https://dart-review.googlesource.com/c/sdk/+/205633
but without renaming TARGET_OS_IPHONE to DART_TARGET_OS_IPHONE.
It also changes uses of TARGET_OS_IOS to
DART_TARGET_OS_MACOS_IOS to be consistent with the rest of the
VM.
TargetConditionals.h for XCode 13 defines several
TARGET_OS_* preprocessor symbols that confuse the
Dart build. There is probably a more targeted fix
for this, but renaming the symbols that Dart uses
will also prevent this problem if more symbols
are added to the platform headers in the future.
See: https://github.com/dart-lang/sdk/issues/46499
TEST=It builds.
Change-Id: Ie775c19dd23cfdf5f65e5ebc6ee4ec3a561676fa
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205860
Commit-Queue: Zach Anderson <zra@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
This reverts commit aa9201b76b.
Reason for revert: blocks G3 roll (b/192627187)
Original change's description:
> [vm] Prefix HOST_OS_* and TARGET_OS_* with DART_
>
> TargetConditionals.h for XCode 13 defines several
> TARGET_OS_* preprocessor symbols that confuse the
> Dart build. There is probably a more targeted fix
> for this, but renaming the symbols that Dart uses
> will also prevent this problem if more symbols
> are added to the platform headers in the future.
>
> See: https://github.com/dart-lang/sdk/issues/46499
>
> TEST=It builds.
> Change-Id: I3b33a03b4a9a14b76d55fe12f8cdefec4b3c3664
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205633
> Commit-Queue: Zach Anderson <zra@google.com>
> Reviewed-by: Siva Annamalai <asiva@google.com>
TBR=rmacnak@google.com,zra@google.com,asiva@google.com
Change-Id: Ib06ca418c7e9d3b4df62c72c033cd39f462f7667
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205790
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
TargetConditionals.h for XCode 13 defines several
TARGET_OS_* preprocessor symbols that confuse the
Dart build. There is probably a more targeted fix
for this, but renaming the symbols that Dart uses
will also prevent this problem if more symbols
are added to the platform headers in the future.
See: https://github.com/dart-lang/sdk/issues/46499
TEST=It builds.
Change-Id: I3b33a03b4a9a14b76d55fe12f8cdefec4b3c3664
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/205633
Commit-Queue: Zach Anderson <zra@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Since we've run out of room for more fields in the Image object header
on 64-bit architectures, the serializer instead creates an ImageHeader
object for precompiled snapshots that is placed at the start of text
segments. The new ImageHeader object contains the following information:
* The offset of the BSS segment from the text segment, previously
stored in the Image object header.
* The relocated address of the text segment in the dynamic shared
object. Due to restrictions when generating assembly snapshots, this
field is only set for ELF snapshots, and so it can also be used to
detect whether a snapshot was compiled to assembly or ELF.
* The offset of the build ID description field from the text segment.
* The length of the build ID description field.
We replace the BSS offset in the Image object header with the offset of
the ImageHeader object within the text segment, so that we can detect
when a given Image has an ImageHeader object available.
There are no methods available on ImageHeader objects, but instead the
Image itself controls access to the information. In particular, the
relocated address method either returns the relocated address
information from the ImageHeader object or from the initialized BSS
depending on the type of snapshot, so the caller need not do this work.
Also, instead of returning the raw offset to the BSS section and having
the caller turn that into an appropriate pointer, the method for
accessing the BSS segment now returns a pointer to the segment.
Bug: https://github.com/dart-lang/sdk/issues/43274
Cq-Include-Trybots: luci.dart.try:vm-precomp-ffi-qemu-linux-release-arm-try,vm-kernel-precomp-android-release-arm64-try,vm-kernel-precomp-android-release-arm_x64-try
Change-Id: I15eae4ad0a088260b127f3d07da79374215b7f56
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/163207
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
(Assignment of libraries to loading units is already done in the kernel generation step.)
After compiling and before serializing, we walk the program and for each Code we assign its Instructions, CodeSourceMap and CompressedStackMap to the loading unit of that Code's defining library. Deduplication may cause Instructions, CodeSourceMaps and CompressedStackMaps to belong to more than one loading unit; in this case the objects are assigned to the root loading unit. Later they can be more precisely assigned to the dominating loading unit.
All objects except some Instructions, CodeSourceMaps and CompressedStackMaps belong to the root loading unit's snapshot. This snapshot is written like an unsplit snapshot, except that when serializing Code, we will write a reference to a stub or null when the Code's Instructions, CodeSourceMap or CompressedStackMap belongs to a non-root loading unit. The snapshots of non-root loading units contain these deferred objects and references to the corresponding Code objects to patch. The types of objects we defer (Instructions, CodeSourceMaps and CompressedStackMaps) usually represent 70+% of the snapshot size.
Bare instructions mode must be disabled when splitting because we cannot have PC-relative calls between loading units. Later we can re-enable this for calls within loading units.
Broken: Compactor probably crashes we can now have an unbounded number of image pages and the compactor assumes a fixed number.
Embedder's guide:
At compile-time, gen_snapshot should be passed --loading_unit_manifest with a path, which will enable splitting and output a mapping from loading unit ids to snapshot output paths.
At runtime, sometime during isolate startup, an embedder should call Dart_SetDeferredLoadHandler, probably near an existing call to Dart_SetLibraryTagHandler. The callback is given a loading unit id, and should eventually call Dart_DeferredLoadComplete[Error].
Bug: https://github.com/dart-lang/sdk/issues/41974
Change-Id: Ib597eb87c8cd634416d5ee1f00629c5550aebb00
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/152427
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
The relocated addresses are populated during BSS::Initialize() for
natively loaded ELF snapshots, and during the non-native loader when it
is used. Putting this information in the BSS segment avoids having to
change the embedder interface, since we only need this information for
AOT snapshots. This also avoids depending on our ELF snapshot layout
to reverse-engineer the DSO base for ELF-compiled snapshots.
We now always print the DSO base for both the VM and isolate in
non-symbolic stack traces, not just for ELF-compiled snapshots. However,
we still only print the relocated addresses in individual stack frames
if we're guaranteed they match those in separately saved debugging
information.
Bug: https://github.com/dart-lang/sdk/issues/41880
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-precomp-mac-release-simarm64-try
Change-Id: I4837262f78e6e73a32eb7e24ef7a68ccb8ec2669
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/148441
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
This reverts commit 4dee4bd204 as it now has the fix for precompiled flow in patchsets 3, 7.
Change-Id: Ib99763a91073df7698e8b597a67e11e557fc131e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/128574
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Also build Dart_LoadELF_Fd on Linux as well to get minimal coverage for Fuchsia.
Change-Id: I4be3eeae3e4559e95413fd60a26b9e6d2edabb32
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/127644
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Fixes symbol resolution on Darwin.
The original commit is in patchset 1.
Change-Id: If71e9a72b8a2f45db2591bfa45ec4018745ee2c4
Cq-Include-Trybots:luci.dart.try:dart-sdk-mac-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/119646
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Also fix the ELF loader to allow segment alignment >page size.
Change-Id: Icc4c2eaae44171e74cc41d9f2b06701acad86a90
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/118983
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
We have had several bugs propagate to Flutter end-users due to our lack of testing of
AOT Assembly snapshots on ARM (SIMARM_X64 in particular), causing reverts of SDK commits
and disrupting the Dart -> Flutter roll.
This leverages our custom ELF loader to load the generated ELF objects, which cannot be
loaded by dlopen() because they are marked with the ARM ABI.
For example, see:
- https://github.com/flutter/flutter/issues/40114
- https://github.com/flutter/flutter/issues/41228
Also do some tree-shaking of the snapshot writers for dart_precompiled_runtime.
Fixes https://github.com/dart-lang/sdk/issues/38433.
Change-Id: I5990769c623b8a13131b1848349af2c0a026272b
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/118569
Reviewed-by: Clement Skau <cskau@google.com>
Reviewed-by: Alexander Thomas <athom@google.com>
Commit-Queue: Samir Jindel <sjindel@google.com>
Also switch some CQ bots using blobs to ELF. Once all embedders have migrated, we will remove blobs
support entirely.
Change-Id: Ie5e8c1187ad6c1af362b5715daafd3641bc8cc0e
Cq-Include-Trybots:luci.dart.try:vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-simarm-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-precomp-bare-linux-release-simarm-try,vm-kernel-precomp-mac-debug-simarm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-precomp-win-release-x64-try,vm-kernel-precomp-android-release-arm-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/116620
Commit-Queue: Samir Jindel <sjindel@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
