The former contents of the VM isolate are now included into each isolate group. This makes each isolate group's heap independent, and in particular allows each heap to be allocated to a separate pointer cage (not done in this CL).
The duplicated stubs that allowed PC relative calls are removed, since the originals can now be the target of PC relative calls.
The bootstrapping needing to load an AppJIT or AppAOT snapshot is reduced to allocating the oddballs. The code is entirely dropped in the AOT runtime, but the JIT runtime still has it to allow for flags to affect the compilation of the stub code. Further refactoring might be able to remove this for the JIT runtime too, with only gen_snapshot knowing how to bootstrap.
Class serialization no longer distinguishes predefined classes.
The page containing null is marked as never-evacuate. null, false and true must not move because the compiler relies on their low bits having certain patterns for some optimizations. (Previously, the entire VM isolate heap never moved.)
Compaction is disabled for IA32. Due to register pressure, some stub calls must not use a scratch register and embed the address of Code.
The page containing the call-through-safepoint stub is frozen when running with --write-protect-code and the stub is created at runtime (instead of loaded from an AppJIT or AppAOT snapshot). This stub must remain executable even during a safepoint, as a foreign call might during return during a safepoint and only block after the stub directs it to the runtime.
The snapshot symbols are renamed to kDartSnapshotData and kDartSnapshotText. There is no need to distinguish the VM isolate's snapshot, and snaphots are per isolate group not per isolate. Aliases with the old names are added to ease migration.
Some global flags that were automatically set based on the VM isolate's snapshot are now isolate group flags and automatically set by the isolate group's snapshot.
TEST=ci
Change-Id: Iee82016057d609112e9b021d178fc3d4d18b5044
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/500621
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
SLSA-Policy-Verified: SLSA Policy Verification Service <devtools-gerritcodereview-exitgate@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
The Mach-O writer puts the unwinding records in a __unwind_info
section, so just find the appropriate section and use its contents
instead of forcing it to be at the end of the segment's memory space.
Create an overload of UnwindingRecordsPlatform::RegisterExecutableMemory
that takes a pointer to the start of the unwinding records for use by
the Mach-O loader.
Add __unwind_info for any executable segments that are not the text
segment as well.
Instead of testing host/target windows plus 64-bit arch, use the
defines provided by platform/unwinding_records.h in the Mach-O
writer and the ELF and Mach-O loaders.
TEST=ci on Windows trybots
Issue: https://github.com/dart-lang/sdk/issues/60307
Change-Id: Iee53c6725a681f44ac98ed9c9aecf1b75853ece5
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-debug-x64-try,vm-mac-release-arm64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-dwarf-linux-product-x64-try,vm-linux-debug-x64-try,vm-mac-debug-arm64-try,vm-gcc-linux-try,vm-aot-win-release-arm64-try,vm-aot-win-release-x64-try,vm-win-release-x64-try,vm-win-release-arm64-try,vm-aot-win-debug-arm64-try,vm-win-debug-arm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/432960
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Adds a Mach-O loader, similar to the existing ELF loader, that
can be used on platforms that do not support loading Mach-O dynamic
libraries via dlopen().
Other changes:
* Renames the --force-load-elf-from-memory command line argument
to --force-load-from-memory.
* Use CPU_TYPE_ANY and CPU_SUBTYPE_ANY for architectures that do
not have specific constants in <mach/machine.h> (e.g., RISCV),
as the snapshot header check after loading also catches architecture
mismatches.
* Emit the unwinding information at the end of the text segment
for Windows Mach-O snapshots as is done for ELF ones.
TEST=vm/dart/unobfuscated_static_symbols_test
vm/dart/use_dwarf_stack_traces_flag_test
Issue: https://github.com/dart-lang/sdk/issues/60307
Change-Id: I34a2a334f47d18d5c4f4a712956e71fd0ac94024
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-debug-x64-try,vm-mac-release-arm64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-dwarf-linux-product-x64-try,vm-linux-debug-x64-try,vm-mac-debug-arm64-try,vm-fuchsia-release-x64-try,vm-fuchsia-release-arm64-try,vm-linux-debug-ia32-try,vm-aot-linux-debug-simarm_x64-try,vm-aot-linux-debug-simriscv32-try,vm-aot-linux-debug-simriscv64-try,vm-aot-linux-release-simarm_x64-try,vm-gcc-linux-try,vm-ubsan-linux-release-arm64-try,vm-aot-win-release-arm64-try,vm-aot-win-release-x64-try,vm-win-release-x64-try,vm-win-release-arm64-try,vm-aot-win-debug-arm64-try,vm-win-debug-arm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/430100
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
This is a reland of commit e6d55c6c2f
Reworks guards for 64-bit Windows unwinding support code so that
it is not included in any 64-bit Windows gen_snapshot executable that
targets a non-64-bit Windows platform.
TEST=ci, build only
Original change's description:
> Add gen_snapshot binaries, producing Linux ARM64/x64 snapshots
>
> Inspired by `//runtime/bin:gen_snapshot_fuchsia`, required for go/dart-cross-compile.
>
> TEST=ci, build only
>
> Change-Id: Ie521c984a8f44d25f3f78d946af9416582a572dc
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/410402
> Reviewed-by: Ryan Macnak <rmacnak@google.com>
> Commit-Queue: Ivan Inozemtsev <iinozemtsev@google.com>
Change-Id: I4f1323ac8f7ab215c2dffeef188f70c466fb62ea
Cq-Include-Trybots: luci.dart.try:vm-win-release-arm64-try,vm-win-release-ia32-try,vm-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/413402
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Ivan Inozemtsev <iinozemtsev@google.com>
Commit-Queue: Ivan Inozemtsev <iinozemtsev@google.com>
This change fixes the following 2 bugs related to unwinding records
on Windows:
1) When cross-compiling from another OS to Windows, unwinding records
were not added to the end of the code section. Later, when loading
AOT snapshot, arbitrary bytes at the end of the code section were
used as the unwinding data, which could result in the errors
returned from Windows API calls.
2) When code section is mapped, its size was rounded up to the page
size; when looking for unwinding record, size of the unwinding
record was subtracted from the rounded size. This is not correct
as unwinding record is placed right at the end of code section,
so code section size should be used before rounding.
Also, magic value is added to the unwinding record in order to
verify that it is preserved and correctly found.
TEST=Manually tested repro from b/320642692
TEST=ffi/ffi_induce_a_crash_test
Fixes b/320642692
Fixes https://github.com/dart-lang/sdk/issues/54206
Change-Id: Id0c6413cd1b759da9e9f25f7617eef55f33b04a2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/346940
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Implements a backend targeting RV32GC and RV64GC, based on Linux standardizing around GC. The assembler is written to make it easy to disable usage of C, but because the sizes of some instruction sequences are compile-time constants, an additional build configuration would need to be defined to make use of it.
The assembler and disassembler cover every RV32/64GC instruction. The simulator covers all instructions except accessing CSRs and the floating point state accessible through such, include accrued exceptions and dynamic rounding mode.
Quirks:
- RISC-V is a compare-and-branch architecture, but some existing "architecture-independent" parts of the Dart compiler assume a condition code architecture. To avoid rewriting these parts, we use a peephole in the assembler to map to compare-and-branch. See Assembler::BranchIf. Luckily nothing depended on taking multiple branches on the same condition code set.
- There are no hardware overflow checks, so we must use Hacker's Delight style software checks. Often these are very cheap: if the sign of one operand is known, a single branch is needed.
- The ranges of RISC-V branches and jumps are such that we use 3 levels of generation for forward branches, instead of the 2 levels of near and far branches used on ARM[64]. Nearly all code is handled by the first two levels with 20-bits of range, with enormous regex matchers triggering the third level that uses aupic+jalr to get 32-bits of range.
- For PC-relative calls in AOT, we always generate auipc+jalr pairs with 32-bits of range, so we never generate trampolines.
- Only a subset of registers are available in some compressed instructions, so we assign the most popular uses to these registers. In particular, THR, TMP[2], CODE and PP. This has the effect of assigning CODE and PP to volatile registers in the C calling convention, whereas they are assigned preserved registers on the other architectures. As on ARM64, PP is untagged; this is so short indices can be accessed with a compressed instruction.
- There are no push or pop instructions, so combining pushes and pops is preferred so we can update SP once.
- The C calling convention has a strongly aligned stack, but unlike on ARM64 we don't need to use an alternate stack pointer. The author ensured language was added to the RISC-V psABI making the OS responsible for realigning the stack pointer for signal handlers, allowing Dart to leave the stack pointer misaligned from the C calling convention's point of view until a foreign call.
- We don't bother with the link register tracking done on ARM[64]. Instead we make use of an alternate link register to avoid inline spilling in the write barrier.
Unimplemented:
- non-trivial FFI cases
- Compressed pointers - No intention to implement.
- Unboxed SIMD - We might make use of the V extension registers when the V extension is ratified.
- BigInt intrinsics
TEST=existing tests for IL level, new tests for assembler/disassembler/simulator
Bug: https://github.com/dart-lang/sdk/issues/38587
Bug: https://github.com/dart-lang/sdk/issues/48164
Change-Id: I991d1df4be5bf55efec5371b767b332d37dfa3e0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/217289
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
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>
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>
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>
Ryan Macnak