Bug 222646 - [JSC] Temporary confusion in debug annotations when advancing llint instruction
Summary: [JSC] Temporary confusion in debug annotations when advancing llint instruction
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2021-03-03 02:31 PST by Xan Lopez
Modified: 2021-03-10 02:32 PST (History)
2 users (show)

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Description Xan Lopez 2021-03-03 02:31:33 PST 
At least on ARMv7 gdb seems to be temporarily confused about what to show when stepping through nextInstruction(). Something like:

(gdb) 
352	    addp advanceReg, PC
(gdb) 
334	    loadb [PB, PC, 1], t0
(gdb) 
1	# Copyright (C) 2011-2020 Apple Inc. All rights reserved.
(gdb) 
0xf625a814	1	# Copyright (C) 2011-2020 Apple Inc. All rights reserved.
(gdb) 
0xf625a816	1	# Copyright (C) 2011-2020 Apple Inc. All rights reserved.
(gdb) 
0xf625a818	1	# Copyright (C) 2011-2020 Apple Inc. All rights reserved.
(gdb) 
257	const BytecodePtrTag = constexpr BytecodePtrTag
(gdb) 
336	    jmp [t1, t0, PtrSize], BytecodePtrTag, AddressDiversified
(gdb) 


The code works fine, so this seems to be just a matter of showing the wrong thing to the user. Haven't tried this on other architectures.
Comment 1 Radar WebKit Bug Importer 2021-03-10 02:32:14 PST 
<rdar://problem/75256922>