Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: ca158eb19b753004c61c9405265669ccfdd8557a
https://github.com/WebKit/WebKit/commit/ca158eb19b753004c61c9405265669ccfdd8557a
Author: Jonas Devlieghere <[email protected]>
Date: 2026-09-04 (Fri, 04 Sep 2026)
Changed paths:
M JSTests/wasm/debugger/lib/environment.py
M JSTests/wasm/debugger/lib/session.py
M JSTests/wasm/debugger/test-wasm-debugger.py
M Source/JavaScriptCore/wasm/WasmModule.h
M Source/JavaScriptCore/wasm/debugger/README.md
M Source/JavaScriptCore/wasm/debugger/WasmModuleManager.cpp
M Source/JavaScriptCore/wasm/debugger/WasmModuleManager.h
M Source/JavaScriptCore/wasm/debugger/WasmQueryHandler.cpp
M Source/JavaScriptCore/wasm/debugger/WasmQueryHandler.h
M Source/JavaScriptCore/wasm/debugger/tests/ExecutionHandlerTest.cpp
M Source/JavaScriptCore/wasm/debugger/tests/TestScripts.cpp
M Source/JavaScriptCore/wasm/debugger/tests/TestScripts.h
Log Message:
-----------
[JSC] Adopt the instance-scoped qWasmGlobal packet form
https://bugs.webkit.org/show_bug.cgi?id=323123
Reviewed by Yijia Huang.
A Wasm global belongs to a module instance, not to a frame. The global
index space is per instance, and DW_OP_WASM_location's global operand
indexes the index space of the instance whose code is being evaluated.
qWasmGlobal took a frame index and used it as a proxy for that instance,
which left the globals of an instance with no active frame out of reach:
a page loading several modules could only inspect whichever one it
happened to be stopped inside.
LLDB has since landed a form that names the instance directly:
qWasmGlobal:<global-index>;instance:<instance-id>
https://github.com/llvm/llvm-project/pull/213176
resolving https://github.com/llvm/llvm-project/issues/212833
This PR adds support for the new packet variant. The id is the module id
already carried in bits 61:32 of a Wasm virtual address. A stub opts in
by advertising qWasmInstance+ in its qSupported reply, which covers any
Wasm query whose scope is an instance rather than a frame. A client that
does not opt in keeps getting the frame form, and the two are told apart
by the presence of the instance: key.
Besides that, I had to make the following changes:
- Because the id is a module id it cannot distinguish two instances of
one module, which have separate globals.
ModuleManager::soleInstanceOfModule() answers only when the module has
exactly one live instance, and QueryHandler::instanceForModule()
additionally accepts a module the debuggee is stopped in, where the
stop itself picks the instance. Anything else replies with an error
rather than guessing, since a wrong value is indistinguishable from a
right one on the wire.
- Also stop qWasmLocal from defaulting an unparsable field to zero.
parseDecimal() returns 0 for a field that is not a number, so a client
sending a field this packet does not have read local 0 of frame 0 and
got a plausible wrong answer instead of an error. This matters more
now that a second packet shape exists.
- Module::debugId() becomes JS_EXPORT_PRIVATE so the new test can link
against it.
- On the test side, setBreakpointsAtAllFunctionEntries() now visits each
module once rather than once per instance. Breakpoints patch module
bytecode, which every instance of a module shares, and patching twice
records the breakpoint opcode itself as the original bytecode. That
was unreachable until a script held two instances of one module.
Test: MultiVMMultipleInstancesPerModule exercises both the sole-instance
and ambiguous paths; testSoleInstanceOfModule derives its expectation
from the instances actually registered, so it holds for every script.
* Source/JavaScriptCore/wasm/WasmModule.h:
* Source/JavaScriptCore/wasm/debugger/README.md:
* Source/JavaScriptCore/wasm/debugger/WasmModuleManager.cpp:
(JSC::Wasm::ModuleManager::soleInstanceOfModule):
* Source/JavaScriptCore/wasm/debugger/WasmModuleManager.h:
* Source/JavaScriptCore/wasm/debugger/WasmQueryHandler.cpp:
(JSC::Wasm::QueryHandler::handleSupported):
(JSC::Wasm::QueryHandler::handleWasmLocal):
(JSC::Wasm::QueryHandler::instanceForModule):
(JSC::Wasm::QueryHandler::instanceForFrame):
(JSC::Wasm::QueryHandler::handleWasmGlobal):
* Source/JavaScriptCore/wasm/debugger/WasmQueryHandler.h:
* Source/JavaScriptCore/wasm/debugger/tests/ExecutionHandlerTest.cpp:
(ExecutionHandlerTest::setBreakpointsAtAllFunctionEntries):
(ExecutionHandlerTest::testSoleInstanceOfModule):
(ExecutionHandlerTest::setupScriptAndWaitForVMs):
(ExecutionHandlerTest::runTests):
* Source/JavaScriptCore/wasm/debugger/tests/TestScripts.cpp:
* Source/JavaScriptCore/wasm/debugger/tests/TestScripts.h:
* JSTests/wasm/debugger/lib/environment.py:
(WebKitEnvironment.__init__):
* JSTests/wasm/debugger/lib/session.py:
(_source_map_command):
(DebugSession.__init__):
* JSTests/wasm/debugger/test-wasm-debugger.py:
(main):
Canonical link: https://commits.webkit.org/320536@main
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