Commit Graph

82 Commits

Author SHA1 Message Date
Ryan Macnak 783cd7fc25 [vm] Include version information in DW_AT_producer.
This follows gcc and clang's behavior.

TEST=readelf
Change-Id: Ic009d9439d1e233afda035d0dfd2592c590c0ce2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/387821
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2024-10-02 19:39:00 +00:00
Ryan Macnak 07e7ec4978 [vm] Include line numbers in DWARF abstract functions.
Tools such as nm expect source positions here and won't try to find the first position in the line number table.

TEST=vm/dart/dwarf_nm_line_numbers_test
Change-Id: I0505b03eea22a75220b4454aaa9c0cde4e9fb698
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/387780
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2024-10-02 18:08:11 +00:00
Vyacheslav Egorov 539ef1fe55 [vm] Fix synthetic line number program
This fixes off by one in the line number program
generation noticed when using perf-annotate.

We were not emitting the row covering last comments
and those rows were were emitting were slightly off.

TEST=profiled code and looked at perf-annotate output

Change-Id: Ia0fe2fa2c830a1be8f6a129c84af01755c19e59a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/331284
Commit-Queue: Slava Egorov <vegorov@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2023-10-23 13:54:04 +00:00
Ryan Macnak 453fce9e77 [vm] Enable clang-tidy for arm, arm64, riscv64, product, release, precompiler.
TEST=ci
Change-Id: I319c932a6f4b6e18d7e53b66d69702bf017e4b93
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/313060
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
2023-07-11 15:13:58 +00:00
Vyacheslav Egorov a52f2b9617 [vm] Rework awaiter stack unwinding.
The main contribution of this CL is unification of disparate
handling of various functions like `Future.timeout`,
`Future.wait`, `_SuspendState.createAsyncCallbacks` and
`_SuspendState._createAsyncStarCallback` into a single
`@pragma('vm:awaiter-link')` which allows Dart developers
to specify where awaiter unwinder should look for the next
awaiter.

For example this allows unwinding to succeed for the code like this:

    Future<int> outer(Future<int> inner) {
      @pragma('vm:awaiter-link')
      final completer = Completer<int>();

      inner.then((v) => completer.complete(v));

      return completer.future;
   }

This refactoring also ensures that we preserve information
(including Function & Code objects) required for awaiter
unwinding across all modes (JIT, AOT and AOT with DWARF stack
traces). This guarantees users will get the same information
no matter which mode they are running in. Previously
we have been disabling awaiter_stacks tests in some AOT
modes - which led to regressions in the quality of produced
stacks.

This CL also cleans up relationship between debugger and awaiter
stack returned by StackTrace.current - which makes stack trace
displayed by debugger (used for stepping out and determinining
whether exception is caught or not) and `StackTrace.current`
consistent.

Finally we make one user visible change to the stack trace:
awaiter stack will no always include intermediate listeners
created through `Future.then`. Previously we would sometimes
include these listeners at the tail of the stack trace,
which was inconsistent.

Ultimately this means that code like this:

    Future<int> inner() async {
      await null;  // asynchronous gap
      print(StackTrace.current); // (*)
      return 0;
    }

    Future<int> outer() async {
      int process(int v) {
        return v + 1;
      }

      return await inner().then(process);
    }

    void main() async {
      await outer();
    }

Produces stack trace like this:

    inner
    <asynchronous suspension>
    outer.process
    <asynchronous suspension>
    outer
    <asynchronous suspension>
    main
    <asynchronous suspension>

And when stepping out of `inner` execution will stop at `outer.process`
first and the next step out will bring execution to `outer` next.

Fixes https://github.com/dart-lang/sdk/issues/52797
Fixes https://github.com/dart-lang/sdk/issues/52203
Issue https://github.com/dart-lang/sdk/issues/47985

TEST=ci

Bug: b/279929839
CoreLibraryReviewExempt: CL just adds @pragma to facilitate unwinding
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-product-x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-dwarf-linux-product-x64-try
Change-Id: If377d5329d6a11c86effb9369dc603a7ae616fe7
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/311680
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
2023-06-30 14:03:03 +00:00
Tess Strickland ecf1968122 [vm] Do not obfuscate code or object symbols in the static symbol table.
Also changes pkg/native_stack_traces to return a parsed MachO file
if the MachO file doesn't contain DWARF information, so we can examine
its static symbol information for the new test.

Issue: https://github.com/flutter/flutter/issues/124715

TEST=vm/dart/unobfuscated_static_symbols

Change-Id: I07d3ced56eeba852ebe4178dfd2b66ebb899eb76
Cq-Include-Trybots: luci.dart.try:vm-aot-dwarf-linux-product-x64-try,vm-aot-linux-product-x64-try,vm-aot-linux-debug-x64-try,vm-aot-linux-release-x64-try,vm-aot-obfuscate-linux-release-x64-try,vm-aot-mac-product-arm64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/305720
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2023-05-31 08:06:08 +00:00
Ryan Macnak f9a6a5bdd2 [vm] Update NULL to nullptr in runtime/vm.
TEST=build
Change-Id: I2834ef7cf7cb7c8770f8167a2438cbedcee5c623
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/292063
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
2023-04-10 18:15:12 +00:00
Ryan Macnak 63e6041ca9 [vm] Update to variadic FATAL.
TEST=ci
Change-Id: Ic6bc784605e10760bb28ea6df34242336a33b4d0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/286947
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2023-03-06 22:06:59 +00:00
Tess Strickland c8ca74d380 [vm] Fix broken failure code in Dwarf::WriteLineNumberProgram.
TEST=riscv64 build combined with CL 279174

Bug: https://github.com/dart-lang/sdk/issues/51051
Change-Id: I016f3a67510ea2a1fa8067aa61fa485ecb5cf172
Cq-Include-Trybots: luci.dart.try:vm-precomp-ffi-qemu-linux-release-riscv64-try,vm-kernel-precomp-asan-linux-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/279177
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2023-01-18 17:21:13 +00:00
Tess Strickland 8bcc849138 [vm] Test and fix resolving DWARF paths in obfuscated mode.
The DWARF generator would always attempt to deobfuscate the URL
retrieved from `Script` objects, whether it came from the `url`
or `resolved_url` field. However, the `resolved_url` field is not
obfuscated, and thus attempting to deobfuscate it could result in a different (and incorrect) string. Thus, only deobfuscate when not
resolving DWARF paths.

TEST=vm/dart{,_2}/use_resolve_dwarf_paths_flag

Bug: https://github.com/dart-lang/sdk/issues/44325
Change-Id: I57a3d47cc78035508082ccba23a2b1cd726ed6bb
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/279086
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2023-01-17 12:34:49 +00:00
Josh Soref 0633041729 Spelling runtime vm
Closes https://github.com/dart-lang/sdk/pull/50786

TEST=ci

GitOrigin-RevId: 781a38e2925ba505f0223ecd578faa9be8e1485c
Change-Id: Ia3c615012d1bac3f0cf64dc01c2ceb40d50d1193
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/276684
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2022-12-29 10:18:02 +00:00
Ryan Macnak 715866aed3 [vm, compiler] Remove quadratic time spent verifying handle lifetime.
Instead of checking whether a handle is a zone handle rather than a scoped handle by iterating the zone handle blocks, reserve an extra slot in debug mode to record the handle's lifetime.

TEST=ci
Bug: https://github.com/dart-lang/sdk/issues/50408
Change-Id: I121c76d02b03e5d2141450077bc6e9da3cb60a5d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/268801
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2022-11-11 18:37:44 +00:00
Tess Strickland c1afa7f85e [vm/compiler] Strip org-dartlang-sdk URI prefix to resolve DWARF paths.
Before, we only stripped `org-dartlang-sdk:///` as a prefix when it was
followed by `sdk/...`, which happens for code compiled with the Dart
SDK. However, the same prefix can show up in Flutter code (e.g.,
`org-dartlang-sdk:///third_party/dart/sdk/...`).  Thus, except for one
case, just strip the prefix at all times when `--resolve-dwarf-paths`
is set, leaving a relative path.

The one case is `org-dartlang-sdk:///flutter/`, which appears in the
resolved version of `dart:ui` (`org-dartlang-sdk:///flutter/lib/ui`),
where the `flutter` isn't part of the actual filesystem path. In this
case, we strip off the `flutter/` as well.

TEST=vm/dart{,_2}/use_resolve_dwarf_paths_flag

Bug: https://github.com/dart-lang/sdk/issues/44325
Change-Id: Ia9abca877e41657089a438d4723ff08a2e16fe69
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-mac-release-arm64-try,vm-kernel-precomp-nnbd-win-release-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/268762
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
2022-11-10 09:33:22 +00:00
Tess Strickland 3b2c41d789 [vm] Make symbol names more user-readable.
Instead of trying to make names assembler-friendly, instead just
quote the symbols names in the assembly output and use user visible
names for function and object symbols.

More specifically:

* This CL changes the symbol name from an assembler-safe version of the
  scrubbed name to an assembler-unsafe version of the user visible name
  that is then quoted when used in assembly output.

* For code symbols, regular stubs are prefixed with `stub`, allocation
  stubs are prefixed with `new` and type testing stubs are prefixed with
  `assert type is` (e.g., `stub Await`, `new RegExp`,
  `assert type is List<Int>`). Function symbols have no prefix.

* Readonly data symbols begin with the type of the readonly data. If
  there's any additional information (e.g., the function name for
  objects like `PcDescriptors` when `SNAPSHOT_BACKTRACE` is defined),
  that follows the type in parentheses.

* For direct-to-ELF snapshots, we allow symbols to have duplicate names.
  Thus, internally we create unique ids for all created symbols and
  refactor the ELF and DWARF subsystems to pass and store these ids
  instead of the symbol names.

* For assembly output, symbols must have unique names. The namer now
  has a `CStringIntMap` that keeps counts of the number of times a
  given symbol name has been generated for assembly output. If the
  symbol name is in the `CStringIntMap`, then the new count in the map
  is added as a suffix to ensure uniqueness.

  For example, the first symbol created using the name `_StringBase.[]`
  has no suffix. If a second symbol is created using the same name,
  the second symbol is instead named `_StringBase.[] (#2)`.

  This also happens for read-only objects with additional information if
  that additional information is not sufficient to make it unique, and
  is added separately from that additional information.

* A further restriction for assembly output is that symbols that begin
  with 'L' have special meaning to the assembler. Thus, we keep the
  old system of prepending such symbol names with an underscore to
  avoid this behavior.

TEST=vm/dart{,_2}/use_add_readonly_data_symbol_flag

Bug: b/248012965
Change-Id: I1b6e876f4fb4f42f4a3b90e03110a34a87a03a7c
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-precomp-nnbd-mac-release-arm64-try,vm-kernel-precomp-mac-product-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/262242
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2022-10-06 10:33:09 +00:00
Vyacheslav Egorov 9158353b5d [vm] Make it easier to get IL / disassembly out
Make `dart compile exe -v` forward gen_snapshot output in
verbose mode.

Fix --write_code_comments_as_synthetic_source_to=... flag. There
was a change to Dwarf writer API which broke it.

Motivated by https://github.com/dart-lang/sdk/issues/50059

TEST=manually

Change-Id: I0431925f724a9b24e938bdb9d7ae1019143da83a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/261360
Commit-Queue: Slava Egorov <vegorov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
2022-09-28 12:21:36 +00:00
Ahmed Ashour 99f0fb5b70 Fix typos
Fixes #49364

TEST=ci

Change-Id: Ic643819c9cdd7b56690981b96b854b1e8d622fff
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/250160
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Lasse Nielsen <lrn@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Brian Wilkerson <brianwilkerson@google.com>
2022-07-12 19:35:22 +00:00
Vyacheslav Egorov df29275537 [vm/aot] Strip google3 scheme in --resolve_dwarf_paths
This makes some internal tools work better with our DWARF information.

TEST=tested manually internally

Bug: b/230585082
Change-Id: I7223ff368dc75b4f45eecee8478f29816670051c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/242560
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
2022-04-27 13:07:21 +00:00
Vyacheslav Egorov 8bdae002f1 [vm] Fix symbolization of future listener frame.
For future listener frames async unwinding produces frames with
`pc_offset` set to 0, because this frames correspond to closures
which will be invoked once the future completes. Such frames
are different from most other frames which correspond to real
call or yield locations within native code and have non-zero
`pc_offset`.

Because there is no call-/yield- site at 0 compiler does not emit
any source location information into CodeSourceMap and consequently
runtime can't produce much beyond file name in the stack trace for
these special frames.

To make matters worse ordering of code objects in the AOT snapshot
could affect symbolization of such frames - sometimes resulting in
an arbitrary token position being attached to the symbolized frame.

This CL adds more special handling of these frames into
StackTrace::ToCString and changes compiler to emit a dummy source
position descriptor for the start of every closure function.

This descriptor is encoded as

    ChangePosition function.token_pos()
    AdvancePC 0

in the CodeSourceMap. This entry is then handled specially when
generating DWARF.

This is reland of https://dart-review.googlesource.com/c/sdk/+/219781 with
fixes for ARM build.

TEST=vm/dart{,_2}/causal_stacks/async_throws_stack_lazy{,_lazy_non_symbolic}_test

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-dwarf-linux-product-x64-try
Change-Id: I06f80c1125422675758917ea12cdf2c70a2f6deb
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219795
Auto-Submit: Slava Egorov <vegorov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
2021-11-10 17:52:03 +00:00
Slava Egorov df38f320ee Revert "[vm] Fix symbolization of future listener frame."
This reverts commit 64d30f848b.

Reason for revert: breaks ARM build.

Original change's description:
> [vm] Fix symbolization of future listener frame.
>
> For future listener frames async unwinding produces frames with
> `pc_offset` set to 0, because this frames correspond to closures
> which will be invoked once the future completes. Such frames
> are different from most other frames which correspond to real
> call or yield locations within native code and have non-zero
> `pc_offset`.
>
> Because there is no call-/yield- site at 0 compiler does not emit
> any source location information into CodeSourceMap and consequently
> runtime can't produce much beyond file name in the stack trace for
> these special frames.
>
> To make matters worse ordering of code objects in the AOT snapshot
> could affect symbolization of such frames - sometimes resulting in
> an arbitrary token position being attached to the symbolized frame.
>
> This CL adds more special handling of these frames into
> StackTrace::ToCString and changes compiler to emit a dummy source
> position descriptor for the start of every closure function.
>
> This descriptor is encoded as
>
>     ChangePosition function.token_pos()
>     AdvancePC 0
>
> in the CodeSourceMap. This entry is then handled specially when
> generating DWARF.
>
> TEST=vm/dart{,_2}/causal_stacks/async_throws_stack_lazy{,_lazy_non_symbolic}_test
>
> Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-dwarf-linux-product-x64-try
> Change-Id: I80740dd2c3cb03d6c03c35e1b3bde2cacbe033e0
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219781
> Commit-Queue: Slava Egorov <vegorov@google.com>
> Reviewed-by: Tess Strickland <sstrickl@google.com>
> Reviewed-by: Clement Skau <cskau@google.com>

TBR=vegorov@google.com,cskau@google.com,sstrickl@google.com

Change-Id: I134ed9e5ccd1dbf3f7c07d046d92be298fe96eb3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-dwarf-linux-product-x64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219794
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>
2021-11-10 16:35:36 +00:00
Vyacheslav Egorov 64d30f848b [vm] Fix symbolization of future listener frame.
For future listener frames async unwinding produces frames with
`pc_offset` set to 0, because this frames correspond to closures
which will be invoked once the future completes. Such frames
are different from most other frames which correspond to real
call or yield locations within native code and have non-zero
`pc_offset`.

Because there is no call-/yield- site at 0 compiler does not emit
any source location information into CodeSourceMap and consequently
runtime can't produce much beyond file name in the stack trace for
these special frames.

To make matters worse ordering of code objects in the AOT snapshot
could affect symbolization of such frames - sometimes resulting in
an arbitrary token position being attached to the symbolized frame.

This CL adds more special handling of these frames into
StackTrace::ToCString and changes compiler to emit a dummy source
position descriptor for the start of every closure function.

This descriptor is encoded as

    ChangePosition function.token_pos()
    AdvancePC 0

in the CodeSourceMap. This entry is then handled specially when
generating DWARF.

TEST=vm/dart{,_2}/causal_stacks/async_throws_stack_lazy{,_lazy_non_symbolic}_test

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-dwarf-linux-product-x64-try
Change-Id: I80740dd2c3cb03d6c03c35e1b3bde2cacbe033e0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219781
Commit-Queue: Slava Egorov <vegorov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Clement Skau <cskau@google.com>
2021-11-10 14:50:23 +00:00
Ryan Macnak 192d909101 [vm] Fix crashes when passing bad paths to --write_retained_reasons_to or --trace_precompiler_to.
TEST=ci
Change-Id: I42465be8cd8a05835d1cc1e5fb23a1fe2d075614
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/212263
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>
2021-09-02 19:47:45 +00:00
Zach Anderson f407419d0a [vm] Reland: Prefix HOST_OS_* and TARGET_OS_* with DART_
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>
2021-07-02 19:06:45 +00:00
Slava Egorov 42164cc140 Revert "[vm] Prefix HOST_OS_* and TARGET_OS_* with DART_"
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>
2021-07-02 14:02:02 +00:00
Tess Strickland d25fdc43ba [vm] Lazily calculate ELF relocations and symbols.
This removes the need for the image snapshot writer to know the
starting memory offset of any ELF sections. Instead, relocation
and symbol information are recorded in the ELF writer to be
resolved during finalization.

This is a step towards being able to reorder sections in the
ELF memory space for better packing into segments. Delaying
relocation and symbol resolution also moves towards merging
multiple text or data sections into a single section if desired.

In addition, this CL removes redundant rows from the DWARF line
number program matrix to reduce the size of debugging information.
Originally, rows were written for every PC offset visited by the
CodeSourceMap. However, no row is needed if the source information
(file, line, column) is the same as the previously written row.

There are also fixes to Utils::{IsInt,IsUint,IsAbsoluteUint} to
allow N >= the bit size of the value.

TEST=Refactoring, so existing tests.

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: I09f87cea214bca06b6fca60cd66138dae6da9e83
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/203766
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
2021-07-02 08:52:49 +00:00
Zach Anderson aa9201b76b [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>
2021-07-02 06:02:48 +00:00
Alexander Markov a98500a139 [vm/aot] Discard Code objects of invisible functions
Previously, Code objects of invisible functions were retained
in order to omit frames corresponding to such functions from stack
traces when stack trace is printed.

This change drops Code objects of invisible functions. That also
means that frames corresponding to such functions are no longer
skipped in binary DWARF stack traces.

In order to account for that, DW_AT_artificial attribute is added to
generated DWARF debug information to mark invisible functions.
Stack trace decoding now looks at this attribute and skips those
frames when symbolizing stack trace.

Flutter gallery in release-sizeopt mode:
Heap size of snapshot objects -4.2% (arm), -4.4% (arm64).

A large application in --dwarf_stack_traces mode:
Number of discarded Code objects increased from 72.4% to 83.7%
(out of all Code objects).
Heap size of Code objects -37.4%.
Heap size of all snapshot objects -5%.

TEST=tests/standalone/dwarf_stack_trace_invisible_functions_test.dart
Issue: https://github.com/dart-lang/sdk/issues/44852
Change-Id: Ib804852aba1e083670f1d9b9d66cbaab7dcdcff9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196583
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2021-04-27 23:31:02 +00:00
Tess Strickland 6b9210df84 [vm/compiler] Fix --resolve-dwarf-paths on Windows.
Fixes https://github.com/dart-lang/sdk/issues/45828

TEST=vm/dart{,_2}/use_resolve_dwarf_paths_flag_test

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-win-release-x64-try
Change-Id: I40c05a5b4dbb370af197a6c50f7e7dc54e29ee4c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196932
Reviewed-by: Régis Crelier <regis@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
2021-04-26 22:44:28 +00:00
Tess Strickland 6730b12edc [vm] Add --resolve-dwarf-paths (disabled by default).
When --resolve-dwarf-paths is enabled, then paths output to DWARF
information will be resolved to either an absolute or relative path.
If this cannot be done, snapshot creation fails.

File URIs are output as absolute paths.

SDK URIs are output as paths relative to the SDK root.

TEST=vm/dart{,_2}/use_resolve_dwarf_paths_flag_test

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-dwarf-linux-product-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-linux-debug-x64-try,vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-precomp-linux-product-x64-try
Change-Id: I63c694f0f707ef6a3d3faa690e001fefe2b26094
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/196491
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2021-04-26 11:44:47 +00:00
Alexander Markov ddfc98337b Reland "[vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces"
This is a reland of b6dc4dad4d

TEST=ci

Original change's description:
> [vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces
>
> The following changes are done in preparation for the removal of Code
> objects in AOT with --dwarf-stack-traces:
>
> * Stack trace objects are extended to hold uword PCs (which may not
>   fit into Smi range).
>
> * Scanning stack frames in GC (StackFrame::VisitObjectPointers)
>   now avoids using Code objects.
>   In order to find CompressedStackMaps it now calls
>   ReversePc::FindCompressedStackMaps.
>
> * Singleton Code object (StubCode::UnknownDartCode()) is prepared as
>   a replacement for Code objects in stack traces. It has
>   PayloadStart() == 0 and Size() == kUwordMax so it includes
>   arbitrary PCs.
>
> * In --dwarf-stack-traces mode, most Code objects obtained from stack
>   frames are replaced with StubCode::UnknownDartCode().
>   This simulates future behavior of ReversePc::Lookup when Code objects
>   will be removed.
>
> Issue: https://github.com/dart-lang/sdk/issues/44852
> Change-Id: I7cec7b8b9396c9cfeca3c256a412ba4e82a7e0c4
> TEST=ci
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182720
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
> Reviewed-by: Tess Strickland <sstrickl@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>

Change-Id: Ia2fc4672a085cd963b7fc103369851df3603590c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/186202
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2021-02-22 10:46:28 +00:00
Alexander Markov fde0ed2e93 Revert "[vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces"
This reverts commit b6dc4dad4d.

Reason for revert: broke package:vm_snapshot_analysis in Flutter
(https://github.com/flutter/flutter/issues/76313).

Original change's description:
> [vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces
>
> The following changes are done in preparation for the removal of Code
> objects in AOT with --dwarf-stack-traces:
>
> * Stack trace objects are extended to hold uword PCs (which may not
>   fit into Smi range).
>
> * Scanning stack frames in GC (StackFrame::VisitObjectPointers)
>   now avoids using Code objects.
>   In order to find CompressedStackMaps it now calls
>   ReversePc::FindCompressedStackMaps.
>
> * Singleton Code object (StubCode::UnknownDartCode()) is prepared as
>   a replacement for Code objects in stack traces. It has
>   PayloadStart() == 0 and Size() == kUwordMax so it includes
>   arbitrary PCs.
>
> * In --dwarf-stack-traces mode, most Code objects obtained from stack
>   frames are replaced with StubCode::UnknownDartCode().
>   This simulates future behavior of ReversePc::Lookup when Code objects
>   will be removed.
>
> Issue: https://github.com/dart-lang/sdk/issues/44852
> Change-Id: I7cec7b8b9396c9cfeca3c256a412ba4e82a7e0c4
> TEST=ci
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182720
> Commit-Queue: Alexander Markov <alexmarkov@google.com>
> Reviewed-by: Tess Strickland <sstrickl@google.com>
> Reviewed-by: Martin Kustermann <kustermann@google.com>

Issue: https://github.com/dart-lang/sdk/issues/44852
Change-Id: I6f66171eecf1133363a7ce56193e782e43a20baf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/185488
Reviewed-by: Zach Anderson <zra@google.com>
Commit-Queue: Alexander Markov <alexmarkov@google.com>
2021-02-18 18:04:29 +00:00
Alexander Markov b6dc4dad4d [vm/aot] Avoid using most Code objects in stack traces with --dwarf-stack-traces
The following changes are done in preparation for the removal of Code
objects in AOT with --dwarf-stack-traces:

* Stack trace objects are extended to hold uword PCs (which may not
  fit into Smi range).

* Scanning stack frames in GC (StackFrame::VisitObjectPointers)
  now avoids using Code objects.
  In order to find CompressedStackMaps it now calls
  ReversePc::FindCompressedStackMaps.

* Singleton Code object (StubCode::UnknownDartCode()) is prepared as
  a replacement for Code objects in stack traces. It has
  PayloadStart() == 0 and Size() == kUwordMax so it includes
  arbitrary PCs.

* In --dwarf-stack-traces mode, most Code objects obtained from stack
  frames are replaced with StubCode::UnknownDartCode().
  This simulates future behavior of ReversePc::Lookup when Code objects
  will be removed.

Issue: https://github.com/dart-lang/sdk/issues/44852
Change-Id: I7cec7b8b9396c9cfeca3c256a412ba4e82a7e0c4
TEST=ci
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/182720
Commit-Queue: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2021-02-17 20:12:32 +00:00
Vyacheslav Egorov d7a57a5df4 [vm] Add feature to connect AOT code to code comments via .debug_line
Option --write_code_comments_as_synthetic_source_to=file tells AOT
compiler to create a file which contains code comments for all code
objects written into an ELF snapshot and then emit a DWARF line number
program into .debug_line section which attributes code to code comments
in a way similar to how our own disassembler does it.

This enables tools like objdump to display our code comments as part of
the disassembly.

This CL also tweaks ifdefs in such a way that IL printer and code comments
facilities is now included into PRODUCT gen_snapshot binary.

TEST=manually run product build with --print-flow-graph and --write_code_comments_as_synthetic_source_to

Change-Id: Id6741013d43e1733b4ddeb34891a4d2fc06b9313
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/181380
Commit-Queue: Vyacheslav Egorov <vegorov@google.com>
Reviewed-by: Tess Strickland <sstrickl@google.com>
Reviewed-by: Alexander Markov <alexmarkov@google.com>
2021-02-02 11:35:00 +00:00
Ryan Macnak b1c09ecd8f [vm] Make naming more consistent when converting between handles, tagged and untagged pointers.
Currently we have things called XPtr which are not what you get from ptr().

Old world:
handle->raw() returns RawObject* (tagged)
raw_obj->ptr() returns RawObject* (untagged)

After 6fe15f6df9:
handle->raw() returns ObjectPtr
obj_ptr->ptr() returns ObjectLayout*

New world:
handle->ptr() returns ObjectPtr
obj_ptr->untag() returns UntaggedObject*

TEST=ci
Change-Id: I6c7f34014cf20737607caaf84979838300d12df2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149367
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
2021-01-15 23:32:02 +00:00
Martin Kustermann 0f76981bb1 [vm/concurrency] Change references to class_table/object_store/heap from Isolate to IsolateGroup
As part of making the compiler and other subsystems independent
of `Isolate` we have to move various state from `Isolate` to
`IsolateGroup`.

The class_table and object_store were already moved to `IsolateGroup`.

This CL only replaces usages of `Isolate::{object_store,class_table}`
with the equivalent in `IsolateGroup`.

Issue https://github.com/dart-lang/sdk/issues/36097

TEST=Pure refactoring - relying on existing test coverage.

Change-Id: I34a0682d715b054d6c5faff077a513980f59a348
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/177126
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2021-01-06 15:22:11 +00:00
Martin Kustermann 18971e409f [vm/concurrency] Move obfuscation related state from Isolate to IsolateGroup
As part of making the compiler independent of `Isolate` we have to move
various state from `Isolate` to `IsolateGroup`.

This CL moves obfuscation related state.

TEST=Pure refactoring - relying on existing test coverage.

Issue https://github.com/dart-lang/sdk/issues/36097

Change-Id: I4b0a74bff9abc200cf8f4ce76b3e1d3d688e664a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/177122
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2021-01-06 11:12:40 +00:00
Tess Strickland d017b8eee8 [vm] Compress CodeSourceMaps by folding opcodes and arguments.
Also delta encode the position/line argument for ChangePosition.

Code size changes on Flutter gallery in release mode from compression:

* ARM7: total -1.39%, readonly -6.47%
* ARM8: total -1.28%, readonly -4.81%

Additional code size changes on Flutter gallery in release mode from
delta encoding position/line:

* ARM7: total -0.48%, readonly -2.37%
* ARM8: total -0.54%, readonly -2.09%

TEST=Existing test on trybots, including stack trace tests and
DWARF decoding tests.

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-debug-x64-try,vm-kernel-precomp-linux-debug-x64-try,vm-kernel-nnbd-linux-debug-x64-try,vm-kernel-linux-debug-x64-try,vm-kernel-linux-release-x64-try,vm-kernel-nnbd-linux-release-x64-try,vm-kernel-precomp-linux-release-x64-try,vm-kernel-precomp-nnbd-linux-release-x64-try,vm-kernel-linux-product-x64-try,vm-kernel-precomp-linux-product-x64-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-linux-release-simarm64-try,vm-kernel-linux-release-simarm64-try,vm-kernel-linux-release-simarm-try,vm-kernel-linux-release-ia32-try
Change-Id: Ibaf96b1d6c1916ce2f7c71942e333ca7a0b86c3e
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/175725
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2020-12-18 00:42:14 +00:00
Tess Strickland 1b50200abd [vm] Simplify symbol naming/address retrieval.
Before, picking a symbol name for a Code object when generating
assembly required adding a placeholder entry in the Dwarf object,
because the Dwarf object separately used a SnapshotTextObjectNamer
to determine the appropriate symbol name to use in relocations.

Instead, now the ImageWriter subclasses are entirely responsible for
creating the symbol name for a given Code object, and that name is
passed when adding the Code object to the Dwarf object.

For Elf output, we eagerly create symbols for sections and Code objects
again in the appropriate symbol table, and so looking up the start of a
given section or Code object can be done simply by asking for the
corresponding symbol's address, removing special case methods and other
workarounds.

We also clean up the generated static and dynamic symbol tables by
only generating local symbols for Code objects and BSS sections (these
are local in assembly output also), and only adding global symbols to
the dynamic symbol table.

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-linux-debug-x64-try,vm-kernel-precomp-linux-debug-simarm_x64-try,vm-kernel-precomp-mac-release-simarm64-try,vm-kernel-mac-debug-x64-try,vm-kernel-win-debug-x64-try,vm-kernel-precomp-win-release-x64-try
Change-Id: Ie40c0c836681e98f345483136bb6860e5588ef30
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166002
Reviewed-by: Martin Kustermann <kustermann@google.com>
2020-10-06 17:10:05 +00:00
Tess Strickland fa03ee7782 [vm] Create a common base class for TextBuffer/ZoneTextBuffer.
Generally, methods that take a *TextBuffer pointer do not care how the
internal buffer is allocated, and so they could be used for either if
both were subclasses of a base class that contained the printing
methods.  This CL makes that base class, and now TextBuffer and
ZoneTextBuffer now share the exact same set of methods for printing to
the internal buffer.

Since the base class is in platform, this does mean dropping the
overload of AddString for Dart String objects that was part of
ZoneTextBuffer.  Instead, this CL just adds an intermediate call to
ToCString() for the small number of callers that used the overload,
keeping the printing interface the same for both.

In addition, one use of TextBuffer that then re-allocated the buffer
contents into the zone manually has been replaced with a ZoneTextBuffer
instead.

Change-Id: I438a085e7e20d55d93987fd7f36afd636f95955f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/157741
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
2020-08-07 18:09:35 +00:00
Ryan Macnak c5a94db091 [vm] Initial implementation of deferred loading.
(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>
2020-07-17 19:29:47 +00:00
Tess Strickland ed0eeaebca [vm/aot] Move precompiled position handling to CodeSourceMap classes.
Since CodeSourceMaps are not serialized when non-symbolic stack traces
are enabled, use a different CSM encoding in this mode. Here, we write
out the line number as before and then the column as a separately
written integer.

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-release-x64-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-linux-release-simarm_x64-try
Change-Id: If9aec2f52551d04eb45626744957e625bcc17d3d
Bug: https://github.com/dart-lang/sdk/issues/42397
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151824
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2020-06-22 09:29:45 +00:00
Tess Strickland 3e40abbc09 [vm/aot] Reland "Keep column information when possible for precompiled mode."
Changes:

Doing this always in precompiled mode meant increased data segment sizes
when CodeSourceMaps are stored, since encoded line/column information is
larger in the LEB-like encoding used. Now we only store column
information when we produce non-symbolic stacks, since the increased
space needed to store the columns is instead in DWARF sections and can
be stripped or elided.

Original description:

Previously, we passed line number information to the stack trace printer
and to DWARF by changing the non-special positions in the CodeSourceMap
to line numbers in precompiled mode. However, doing this lost column
information.

We get the column information back in the majority of cases by encoding
the line number and column information when neither is too large to pack
together into 30 bits. (Here, 20 bits for line and 10 bits for column.)
Otherwise, we just store the line information as before, though due to
using a bit to encode whether column info exists, it's reduced to 30
bits. If the line info is too big for that, we just return kNoSourcePos.

Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-release-x64-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-linux-release-simarm_x64-try
Change-Id: Ia8baee71468da6100a170fa305d03059ffd17f78
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151822
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
2020-06-19 13:50:03 +00:00
Martin Kustermann db8a105de7 Revert "[vm/aot] Keep column information when possible for precompiled mode."
This reverts commit 7c34a80c11.

Reason for revert: This change seems to cause >2% code size regression
in flutter-release mode.

Original change's description:
> [vm/aot] Keep column information when possible for precompiled mode.
> 
> Previously, we passed line number information to the stack trace printer
> and to DWARF by changing the non-special positions in the CodeSourceMap
> to line numbers in precompiled mode. However, doing this lost column
> information.
> 
> We get the column information back in the majority of cases by encoding
> the line number and column information when neither is too large to pack
> together into 30 bits. (Here, 20 bits for line and 10 bits for column.)
> Otherwise, we just store the line information as before, though due to
> using a bit to encode whether column info exists, it's reduced to 30
> bits. If the line info is too big for that, we just return kNoSourcePos.
> 
> Cq-Include-Trybots: luci.dart.try:vm-kernel-precomp-nnbd-linux-release-x64-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-linux-release-simarm_x64-try
> Change-Id: Id1c826f10871e2f304fa40a59d8b704404d3a2c9
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151507
> Commit-Queue: Tess Strickland <sstrickl@google.com>
> Reviewed-by: Ryan Macnak <rmacnak@google.com>

TBR=rmacnak@google.com,alexmarkov@google.com,sstrickl@google.com

Change-Id: I5cf97543d1ac2731bb27bdb58ae97af6f22f2cfb
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
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Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151820
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
2020-06-18 19:57:44 +00:00
Tess Strickland 7c34a80c11 [vm/aot] Keep column information when possible for precompiled mode.
Previously, we passed line number information to the stack trace printer
and to DWARF by changing the non-special positions in the CodeSourceMap
to line numbers in precompiled mode. However, doing this lost column
information.

We get the column information back in the majority of cases by encoding
the line number and column information when neither is too large to pack
together into 30 bits. (Here, 20 bits for line and 10 bits for column.)
Otherwise, we just store the line information as before, though due to
using a bit to encode whether column info exists, it's reduced to 30
bits. If the line info is too big for that, we just return kNoSourcePos.

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Change-Id: Id1c826f10871e2f304fa40a59d8b704404d3a2c9
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/151507
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2020-06-18 10:45:33 +00:00
Tess Strickland e160698933 [vm/aot] Delay relocated address calculation for static symbols.
Since we no longer add the symbol for a given code object to the Elf
object when writing the contents of the text segment, we don't need to
calculate the relocated address that early. Instead, just store which
text segment the instructions payload belongs to as well as its offset
into the segment contents and let Elf::Finalize() calculate the
relocated address when creating the symbol.

This removes one need for knowing the segment base address when writing
the segment contents. The remaining needs are related to BSS usage:

* Calculating the BSS offset from the text segment for the Image header.
* Fixing up BSS relocations in instructions payloads.

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Change-Id: I8be860a7a7111721e6f546154a0814f4d16ac634
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150929
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Clement Skau <cskau@google.com>
2020-06-12 11:34:02 +00:00
Tess Strickland 83d4f3af61 [vm/aot] Rework Dwarf object to be output-agnostic.
Previously, we created a separate DWARF object for each possible output.
For the most part, the information stored in each DWARF object was the
same, but the DWARF object was responsible for keeping track of abstract
origin addresses (in the non-assembly case) and for actually generating
the desired output (assembly or binary).

Instead, abstract out the output formatting into a DwarfWriteStream,
whose subclasses handle both the final output format and certain details
that differ between assembly and binary outputs. With this, the DWARF
class no longer depends on having direct access to the ELF file if being
used to generate ELF sections, and as such is output agnostic.

Now, if we have one or more outputs that contain DWARF information, we
only generate a single DWARF object that is shared across these outputs.
The only additional change required is in Dwarf::AddCode(), which now
handles being called multiple times for the same Code object.

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Change-Id: I71de887a07a673164b3ccfa7fbbab2ccef80c576
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/150302
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>
2020-06-11 08:57:59 +00:00
Tess Strickland df435c9235 [vm/aot] For ELF output, make DW_AT_high_pc the end of the isolate text.
This avoids treating addresses within segments added after the isolate
text section as valid PC addresses for our DWARF information.

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Change-Id: Ibdac611d97b5a24226c226a3904c958f131ab961
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149290
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2020-06-08 08:35:32 +00:00
Tess Strickland b6b78fcd50 [vm] Ensure line information in DWARF is unsigned.
The DWARF standard specifically states that line number information is
unsigned (with 0 denoting no line number information). However, we
currently use special (negative) token positions in our DWARF
information directly as line numbers. Instead, convert any special token
positions to a line number of 0.

Fixes: https://github.com/dart-lang/sdk/issues/41860

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Change-Id: Ic26e553d6a6d642b456fe45760650de9c8478d16
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/147902
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Daco Harkes <dacoharkes@google.com>
2020-05-13 15:43:11 +00:00
Tess Strickland 245a574301 [vm] Make the ELF static symbol table a superset of the dynamic one.
Only the case for unstripped snapshots and debugging information.
Stripped snapshots still have no static symbol table, only the
dynamic one.

Fixes: https://github.com/dart-lang/sdk/issues/41783

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Change-Id: Ibd82334597d34267a3b9e45a673d23c3f9e3fcb0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/147182
Commit-Queue: Tess Strickland <sstrickl@google.com>
Reviewed-by: Aske Simon Christensen <askesc@google.com>
2020-05-12 07:21:48 +00:00
Tess Strickland 9e14e7da2a [vm] Add correct lower bound for DWARF information in ELF snapshots.
When generating DWARF for assembly snapshots, we use a lower bound
of the start of the isolate instructions section. Use the same bound
when generating DWARF for ELF snapshots as well.

Also avoid generating rows in the line number program for address 0.

Fixes https://github.com/dart-lang/sdk/issues/41756.

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Change-Id: I3d17e09ff8af3ba6fc70dcd6859d9b298e941ecf
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/146584
Reviewed-by: Ryan Macnak <rmacnak@google.com>
2020-05-11 08:41:17 +00:00
Teagan Strickland 5f8802b82f [vm] Add sizes to ELF static symbols for Code payloads.
Change-Id: I7868ec621e08773b7d379e95fe091e820bf29c94
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Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/139807
Reviewed-by: Daco Harkes <dacoharkes@google.com>
Commit-Queue: Teagan Strickland <sstrickl@google.com>
2020-03-18 10:23:36 +00:00