[Webkit-unassigned] [Bug 250823] New: Improve VMInspector::dumpRegisters().
bugzilla-daemon at webkit.org
bugzilla-daemon at webkit.org
Wed Jan 18 20:39:20 PST 2023
https://bugs.webkit.org/show_bug.cgi?id=250823
Bug ID: 250823
Summary: Improve VMInspector::dumpRegisters().
Product: WebKit
Version: WebKit Nightly Build
Hardware: Unspecified
OS: Unspecified
Status: NEW
Severity: Normal
Priority: P2
Component: JavaScriptCore
Assignee: webkit-unassigned at lists.webkit.org
Reporter: mark.lam at apple.com
1. Change the order of the dump to go from low memory to high memory. This makes the dump more intuitive to read because:
a. C++ structures are dumped that way in debuggers, and
b. Dumping this way allows us to dump the caller frame next, and the memory dumps just stitches together naturally.
2. Add VMInspector::vmForCallFrame() to find the VM for a CallFrame instead of relying on a CodeBlock being present.
This allows us to ...
3. Add rudimentary support for dumping EntryFrame, as well as Wasm and native frames.
4. Also changed the layout of the dumped CallFrame registers to have more useful info while being easier to read.
For example, an old dump looks like this:
```
-----------------------------------------------------------------------------
use | address | value
-----------------------------------------------------------------------------
[r 10 arguments[ 5]] | 0x16fdfbfb0 | 0xa Undefined
[r 9 arguments[ 4]] | 0x16fdfbfa8 | 0xfffe000000000000 Int32: 0
[r 8 arguments[ 3]] | 0x16fdfbfa0 | 0x10409c240 Object: 0x10409c240 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x30000afd0:[0xafd0/45008, Object, (2/6, 0/0){module:0, instance:1}, NonArray, Proto:0x103011968, Leaf]), StructureID: 45008
[r 7 arguments[ 2]] | 0x16fdfbf98 | 0xfffe000000000001 Int32: 1
[r 6 arguments[ 1]] | 0x16fdfbf90 | 0x103038de8 Object: 0x103038de8 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x3000077b0:[0x77b0/30640, Generator, (0/0, 0/0){}, NonArray, Proto:0x103012ae8, Leaf]), StructureID: 30640
[r 5 this] | 0x16fdfbf88 | 0x10300e268 Object: 0x10300e268 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x300008720:[0x8720/34592, JSProxy, (0/0, 0/0){}, NonArray, Proto:0x103011968, Leaf]), StructureID: 34592
-----------------------------------------------------------------------------
[ArgumentCount] | 0x16fdfbf80 | 5
[ReturnVPC] | 0x16fdfbf80 | 399 (line 20)
[Callee] | 0x16fdfbf78 | 0x10408e100 Object: 0x10408e100 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x3000057c0:[0x57c0/22464, Function, (0/0, 0/0){}, NonArray, Proto:0x1030305a8, Leaf]), StructureID: 22464
[CodeBlock] | 0x16fdfbf70 | 0x1040d8580 #Bhpb2b:[0x1040d8580->0x104099980, LLIntFunctionCall, 412]
[ReturnPC] | 0x16fdfbf68 | 0x11a470248
[CallerFrame] | 0x16fdfbf60 | 0x16fdfc020
-----------------------------------------------------------------------------
[r -1 CalleeSaveReg] | 0x16fdfbf58 | 0xfffe000000000002 Int32: 2
[r -2 CalleeSaveReg] | 0x16fdfbf50 | 0xfffe000000000000 Int32: 0
[r -3 CalleeSaveReg] | 0x16fdfbf48 | 0x103030f40
[r -4 CalleeSaveReg] | 0x16fdfbf40 | 0x103059770
[r -5 ] | 0x16fdfbf38 | 0xa Undefined
[r -6 ] | 0x16fdfbf30 | 0xa Undefined
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
```
The new dump now looks like this:
```
Registers for JS frame 0x16fdfbfe0 (entryFrame 0x16fdfc2d0):
-----------------------------------------------------------------------------
VirtualRegister : address value
---------------------------------------------------- Outgoing Args + Misc ---
------------------------------------------------------------------ Locals ---
-6 : 0x16fdfbfb0 0x102038428 Object: 0x102038428 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x300005520:[0x5520/21792, JSGlobalLexicalEnvironment, (0/0, 0/0){}, NonArray, Leaf]), StructureID: 21792
-5 : 0x16fdfbfb8 0x102038428 Object: 0x102038428 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x300005520:[0x5520/21792, JSGlobalLexicalEnvironment, (0/0, 0/0){}, NonArray, Leaf]), StructureID: 21792
------------------------------------------------------------ Callee Saves ---
-4 CalleeSaveReg : 0x16fdfbfc0 0x102059130
-3 CalleeSaveReg : 0x16fdfbfc8 0x102030f40
-2 CalleeSaveReg : 0x16fdfbfd0 0xfffe000000000000 Int32: 0
-1 CalleeSaveReg : 0x16fdfbfd8 0xfffe000000000002 Int32: 2
-------------------------------------------------------- CallFrame Header ---
0 CallerFrame : 0x16fdfbfe0 0x16fdfc0a0
1 ReturnPC : 0x16fdfbfe8 0x11a470248 (pac signed 0xff1c00011a470248)
2 CodeBlock : 0x16fdfbff0 0x1050d8580 #D6UySe:[0x1050d8580->0x105099980, LLIntFunctionCall, 644]
3 Callee : 0x16fdfbff8 0x10508e100 Object: 0x10508e100 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x3000057c0:[0x57c0/22464, Function, (0/0, 0/0){}, NonArray, Proto:0x1020305a8]), StructureID: 22464
4.1 ReturnVPC : 0x16fdfc000 632 (line 20)
4.2 ArgumentCount : 0x16fdfc000 5
--------------------------------------------------------------- Arguments ---
5 this : 0x16fdfc008 0x10200e1c8 Object: 0x10200e1c8 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x300008720:[0x8720/34592, JSProxy, (0/0, 0/0){}, NonArray, Proto:0x102011968, Leaf]), StructureID: 34592
6 arguments[1] : 0x16fdfc010 0x102038de8 Object: 0x102038de8 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x3000077b0:[0x77b0/30640, Generator, (0/0, 0/0){}, NonArray, Proto:0x102012ae8, Leaf]), StructureID: 30640
7 arguments[2] : 0x16fdfc018 0xfffe000000000001 Int32: 1
8 arguments[3] : 0x16fdfc020 0x10509c240 Object: 0x10509c240 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x30000b740:[0xb740/46912, Object, (2/6, 0/0){module:0, instance:1}, NonArray, Proto:0x102011968, Leaf]), StructureID: 46912
9 arguments[4] : 0x16fdfc028 0xfffe000000000000 Int32: 0
10 arguments[5] : 0x16fdfc030 0x1050e0130 Object: 0x1050e0130 with butterfly 0x0(base=0xfffffffffffffff8) (Structure 0x300005c20:[0x5c20/23584, JSLexicalEnvironment, (0/0, 0/0){}, NonArray, Leaf]), StructureID: 23584
--------------------------------------------------------------------- End ---
```
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