1673818 - Clarify that wasm memories are 32-bit wasm memories + decouple mem limit from buffer limit

Status: RESOLVED FIXED

(Core :: JavaScript: WebAssembly, enhancement, P2)

Description

[Lars T Hansen [:lth]]

Preliminary work for larger array buffers. We need to clarify that we currently have only 32-bit wasm memories, so that there's no room for confusion about that. And we also need to decouple wasm's memory limit from the arraybuffer's limit, because a 32-bit memory will have a memory limit that is much lower than the arraybuffer's limit on 64-bit platforms.

Comment 1

[Lars T Hansen [:lth]]

Attachment: Bug 1673818 - Decouple memory limit from buffer limit, clarify 32-bit memories. r?rhunt

This patch does two intertwined things:

• it clarifies throughout that the wasm memories we are currently
  using are 32-bit memories by adding '32' in a number of names and
  introducing a MemoryKind enum that is (for now) used to carry the
  type of memory we have.

• it stops using the MaxBufferByteLength for anything to do with
  memory length checking, instead introducing checks against a limit
  derived from MaxMemory32Pages where that is appropriate. All
  remaining uses of MaxBufferByteLength are strictly about the
  buffer maximum, not the memory's maximum.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7c2ee39c8744
Decouple memory limit from buffer limit, clarify 32-bit memories. r=rhunt

Comment 3

[Sandor Molnar[:smolnar]]

Backed out for causing sm build bustages in MacroAssembler-arm64 :

Backout link: https://hg.mozilla.org/integration/autoland/rev/8f0fadc9e78b9d155e833f3b25d940e13cb7fed9

Push with failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Crunning%2Cpending%2Crunnable&revision=7c2ee39c8744463b3075270d4b0e1a922a96591f

Failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=320096428&repo=autoland&lineNumber=2754

"make[3]: Entering directory '/builds/worker/workspace/obj-spider/mfbt'
[task 2020-10-29T07:15:30.757Z] mkdir -p '.deps/'
[task 2020-10-29T07:15:30.759Z] mfbt/lz4.o
[task 2020-10-29T07:15:30.759Z] /builds/worker/fetches/clang/bin/clang -std=gnu99 -o lz4.o -c -I/builds/worker/workspace/obj-spider/dist/system_wrappers -include /builds/worker/checkouts/gecko/config/gcc_hidden.h -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -fstack-protector-strong -ftrivial-auto-var-init=pattern -DDEBUG=1 -DIMPL_MFBT -DLZ4LIB_VISIBILITY= -I/builds/worker/checkouts/gecko/mfbt -I/builds/worker/workspace/obj-spider/mfbt -I/builds/worker/checkouts/gecko/mfbt/double-conversion -I/builds/worker/workspace/obj-spider/dist/include -I/builds/worker/workspace/obj-spider/dist/include/nspr -fPIC -include /builds/worker/workspace/obj-spider/js/src/js-confdefs.h -DMOZILLA_CLIENT -Qunused-arguments -ffunction-sections -fdata-sections -fno-math-errno -pthread -pipe -g -O3 -fno-omit-frame-pointer -funwind-tables -Werror -Qunused-arguments -Wall -Wbitfield-enum-conversion -Wempty-body -Wignored-qualifiers -Wpointer-arith -Wshadow-field-in-constructor-modified -Wsign-compare -Wtype-limits -Wunreachable-code -Wunreachable-code-return -Wclass-varargs -Wfloat-overflow-conversion -Wfloat-zero-conversion -Wloop-analysis -Werror=non-literal-null-conversion -Wstring-conversion -Wtautological-overlap-compare -Wtautological-unsigned-enum-zero-compare -Wtautological-unsigned-zero-compare -Wno-error=tautological-type-limit-compare -Wno-error=deprecated-declarations -Wno-error=array-bounds -Wno-error=backend-plugin -Wno-error=return-std-move -Wno-error=atomic-alignment -Wno-error=deprecated-copy -Wformat -Wformat-security -Wno-gnu-zero-variadic-macro-arguments -Werror=implicit-function-declaration -Wno-psabi -fexperimental-new-pass-manager -MD -MP -MF .deps/lz4.o.pp /builds/worker/checkouts/gecko/mfbt/lz4/lz4.c
[task 2020-10-29T07:15:30.759Z] mfbt/lz4frame.o
[task 2020-10-29T07:15:30.810Z] In file included from Unified_cpp_js_src_jit14.cpp:2:
[task 2020-10-29T07:15:30.810Z] /builds/worker/checkouts/gecko/js/src/jit/arm64/MacroAssembler-arm64.cpp:1413:14: error: no member named 'boundsCheckLimit' in 'TlsData'
[task 2020-10-29T07:15:30.810Z] offsetof(wasm::TlsData, boundsCheckLimit));
[task 2020-10-29T07:15:30.810Z] ^ ~~~~~~~~~~~~~~~~
[task 2020-10-29T07:15:30.810Z] /builds/worker/fetches/clang/lib/clang/11.0.0/include/stddef.h:104:24: note: expanded from macro 'offsetof'
[task 2020-10-29T07:15:30.810Z] #define offsetof(t, d) __builtin_offsetof(t, d)
[task 2020-10-29T07:15:30.810Z] ^ ~
[task 2020-10-29T07:15:30.810Z] /builds/worker/workspace/obj-spider/dist/include/mozilla/Assertions.h:414:24: note: expanded from macro 'MOZ_ASSERT'
[task 2020-10-29T07:15:30.810Z] ("MOZ_ASSERT", VA_ARGS))
[task 2020-10-29T07:15:30.810Z] ^~~~~~~~~~~
[task 2020-10-29T07:15:30.810Z] /builds/worker/workspace/obj-spider/dist/include/mozilla/Assertions.h:404:33: note: expanded from macro 'MOZ_ASSERT_GLUE'
[task 2020-10-29T07:15:30.810Z] #define MOZ_ASSERT_GLUE(a, b) a b
[task 2020-10-29T07:15:30.810Z] ^
[task 2020-10-29T07:15:30.810Z] /builds/worker/workspace/obj-spider/dist/include/mozilla/Assertions.h:385:40: note: expanded from macro 'MOZ_ASSERT_HELPER1'
[task 2020-10-29T07:15:30.810Z] MOZ_VALIDATE_ASSERT_CONDITION_TYPE(expr);
[task 2020-10-29T07:15:30.810Z] ^~~~
[task 2020-10-29T07:15:30.810Z] /builds/worker/workspace/obj-spider/dist/include/mozilla/Assertions.h:367:58: note: expanded from macro 'MOZ_VALIDATE_ASSERT_CONDITION_TYPE'
[task 2020-10-29T07:15:30.810Z] mozilla::detail::AssertionConditionType<decltype(x)>::isValid,
[task 2020-10-29T07:15:30.810Z] ^
[task 2020-10-29T07:15:30.810Z] In file included from Unified_cpp_js_src_jit14.cpp:2:
[task 2020-10-29T07:15:30.810Z] /builds/worker/checkouts/gecko/js/src/jit/arm64/MacroAssembler-arm64.cpp:1413:14: error: no member named 'boundsCheckLimit' in 'TlsData'
[task 2020-10-29T07:15:30.810Z] offsetof(wasm::TlsData, boundsCheckLimit));"

Comment 4

[Lars T Hansen [:lth]]

Fixed this and did a full try run: https://treeherder.mozilla.org/#/jobs?repo=try&revision=26416458bbf150b4f6dbfc228426a960590b9642

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d606ab4b0dc1
Decouple memory limit from buffer limit, clarify 32-bit memories. r=rhunt

Comment 6

[Cristina Coroiu [:ccoroiu]]

https://hg.mozilla.org/mozilla-central/rev/d606ab4b0dc1