<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=Windows-1252">
<style type="text/css" style="display:none;"> P {margin-top:0;margin-bottom:0;} </style>
</head>
<body dir="ltr">
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Hi Rafael,</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
I think the particular arrangement ASM has for line numbers is probably due to that line number was a later addition to a very early version of ASM: the label argument is largely redundant. If the extra label is useful, I guess that will be added for type-use
annotations in code too, which ASM obviously didn't do.</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Also, I don't see the point of patching line numbers: this still requires you to know the labels ahead of time. If you really, really need this pattern, you can first generate methods in a class, and process with ClassBuilder::transformingMethods (which, at
this stage, has a complete code view that your line number computation may need to access) to add line numbers.</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
<br>
</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Regards,</div>
<div class="elementToProof" style="font-family: Aptos, Aptos_EmbeddedFont, Aptos_MSFontService, Calibri, Helvetica, sans-serif; font-size: 12pt; color: rgb(0, 0, 0);">
Chen Liang</div>
<div id="appendonsend"></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Rafael Winterhalter <rafael.wth@gmail.com><br>
<b>Sent:</b> Monday, November 11, 2024 4:57 PM<br>
<b>To:</b> Adam Sotona <adam.sotona@oracle.com><br>
<b>Cc:</b> classfile-api-dev <classfile-api-dev@openjdk.org>; Chen Liang <chen.l.liang@oracle.com><br>
<b>Subject:</b> Re: [External] : Re: Mapping byte code offsets in custom code attributes</font>
<div> </div>
</div>
<div>
<div dir="ltr">
<div>I fully agree that the current API covers 99% of the use cases. However, in ASM, labels are visited before line numbers. The actual line numbers can be patched in at any time. If you are working with a large ASM-based application, and you want to migrate
this application to using the Class File API, this migration is much less straight-forward.</div>
<div><br>
</div>
<div>At the same time, this is an API limitation, and not inherent with the class file API. It feels like an unnecessary burden that could easily be resolved.<br>
</div>
</div>
<br>
<div class="x_gmail_quote">
<div dir="ltr" class="x_gmail_attr">Am Mo., 11. Nov. 2024 um 21:21 Uhr schrieb Adam Sotona <<a href="mailto:adam.sotona@oracle.com">adam.sotona@oracle.com</a>>:<br>
</div>
<blockquote class="x_gmail_quote" style="margin:0px 0px 0px 0.8ex; border-left:1px solid rgb(204,204,204); padding-left:1ex">
<div class="x_msg8145892309206543986">
<div lang="EN-US" style="">
<div class="x_m_773723447759013447WordSection1">
<p class="x_MsoNormal"><span style="font-size:11pt">Hi Rafael,<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Here is an example method:<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">static</span><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">void</span><span style="font-size:10pt; font-family:"Courier New"; color:black">
<b><i>m</i></b>() {<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">int</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> a = 1;<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">int</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> b = 2;<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> a = 3;<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> b = 4;<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> }<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u> <u></u></span></p>
<p class="x_MsoNormal">This is a sample transformation manipulating line numbers and local variables:<u></u><u></u></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> ClassFile.<i>of</i>().transformClass(clm, ClassTransform.<i>transformingMethodBodies</i>((cob, coe) -> {<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">switch</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> (coe) {<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">case</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> LineNumber ln -><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> cob.lineNumber(ln.line() + 100);
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(150,150,150)">// change line numers</span><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">case</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> LocalVariable lv
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">when</span><span style="font-size:10pt; font-family:"Courier New"; color:black">
<a href="https://urldefense.com/v3/__http://lv.name__;!!ACWV5N9M2RV99hQ!KreDZAW-VisNlVfaaDmJdOzX8VLJJX-qNrPFUKbK4TA4fMrqOokLXbz8pKyQf6ZuViqSXLiM1XQCs2l2WUILKQ$" target="_blank">
lv.name</a>().equalsString(</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(30,147,71)">"a"</span><span style="font-size:10pt; font-family:"Courier New"; color:black">) -><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> cob.localVariable(lv.slot(),
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(30,147,71)">"x"</span><span style="font-size:10pt; font-family:"Courier New"; color:black">, lv.typeSymbol(), cob.startLabel(), lv.endScope());
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(150,150,150)">// rename var a to x and change its start scope</span><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">case</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> LocalVariable
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">_</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> -> {}
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(150,150,150)">// drop var b</span><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black">
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(51,107,221)">default</span><span style="font-size:10pt; font-family:"Courier New"; color:black"> -> cob.with(coe);<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> }<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> }<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> ).andThen(ClassTransform.<i>transformingMethodBodies</i>(CodeTransform.<i>endHandler</i>(cob -> cob<u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> .localVariable(1,
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(30,147,71)">"y"</span><span style="font-size:10pt; font-family:"Courier New"; color:black">, ConstantDescs.</span><i><span style="font-size:10pt; font-family:"Courier New"; color:rgb(206,84,184)">CD_int</span></i><span style="font-size:10pt; font-family:"Courier New"; color:black">,
cob.startLabel(), cob.endLabel()) </span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(150,150,150)">// add var y</span><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u><u></u></span></p>
<p class="x_MsoNormal" style="background:white"><span style="font-size:10pt; font-family:"Courier New"; color:black"> .lineNumber(999)))));
</span><span style="font-size:10pt; font-family:"Courier New"; color:rgb(150,150,150)">// add line number</span><span style="font-size:10pt; font-family:"Courier New"; color:black"><u></u><u></u></span></p>
<p class="x_MsoNormal"><u></u> <u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">And as you can see there are no custom attributes nor bytecode offset conversions necessary.<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Yes, Class-File API contains several raw points where bytecode offsets are intentionally exposed to support specific use cases, however no one is obliged to use them.
<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt">I hope this finally addressed your questions.<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Adam<u></u><u></u></span></p>
<p class="x_MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<div id="x_m_773723447759013447mail-editor-reference-message-container">
<div>
<div>
<div style="border-width:1pt medium medium; border-style:solid none none; border-color:rgb(181,196,223) currentcolor currentcolor; padding:3pt 0in 0in">
<p class="x_MsoNormal" style="margin-bottom:12pt"><b><span style="color:black">From:
</span></b><span style="color:black">Rafael Winterhalter <<a href="mailto:rafael.wth@gmail.com" target="_blank">rafael.wth@gmail.com</a>><br>
<b>Date: </b>Monday, 11 November 2024 at 18:59<br>
<b>To: </b>Adam Sotona <<a href="mailto:adam.sotona@oracle.com" target="_blank">adam.sotona@oracle.com</a>>, classfile-api-dev <<a href="mailto:classfile-api-dev@openjdk.org" target="_blank">classfile-api-dev@openjdk.org</a>>, Chen Liang <<a href="mailto:chen.l.liang@oracle.com" target="_blank">chen.l.liang@oracle.com</a>><br>
<b>Subject: </b>Re: [External] : Re: Mapping byte code offsets in custom code attributes<u></u><u></u></span></p>
</div>
<div>
<div>
<p class="x_MsoNormal">(I realized that I did not reply-all and wanted to add the mailing list again. Some of the discussion can be found in the quotation below, if anyone is reading.)<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="x_MsoNormal">I cannot describe a use case that goes beyond mere printing where I could work with BCIs in the context of a Class File API represented list of instructions. If I wanted to create a CharacterRangeTableAttribute, I would always have to
resolve BCIs to labels. Why not let the AttributeMapper handle this translation consistently but require BCI as input to the factory method? To me, this seems more error prone and less type-safe.<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="x_MsoNormal">Maybe I should ask the question differently: what led to a choice of using labels over BCIs when dealing with stack map frames, and for the runtime (in-)visible type annotations? I think the answer is that those are more convenient, despite
that they are inlined. I cannot make sense that two groups of attributes are represented in two different ways, when labels are obviously more expressive. I get that type annotations and stack map frames might be more central attributes, where the others are
more often used by power users. But also power users would benefit from the better abstraction, so I think this should be the target? If the answer is that there is no time to adjust the API, I wonder if one should avoid exposing those four other attributes
until there is time, especially with Java 24 likely being less adopted compared to Java 25 where Oracle plans to offer LTS. I feel like exposing BCIs is premature, if labels could be used, and it would be a shame to lose the opportunity to use labels within
these four info attributes. I already see the BCI factories and methods being deprecated in a future release, so why not aim for the best solution already today?<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="x_MsoNormal">I understand that this API change is out of scope for JDK-8341274, but I would love to see a follow up change that adjusts those four interfaces to use labels and not BCIs, such that the Class File API is consistent. If possible within
the release of Java 24, or Java 25 with the BCI methods not exposed before that.<u></u><u></u></p>
</div>
</div>
<p class="x_MsoNormal"><u></u> <u></u></p>
<div>
<div>
<p class="x_MsoNormal">Am Mo., 11. Nov. 2024 um 16:19 Uhr schrieb Adam Sotona <<a href="mailto:adam.sotona@oracle.com" target="_blank">adam.sotona@oracle.com</a>>:<u></u><u></u></p>
</div>
<blockquote style="border-width:medium medium medium 1pt; border-style:none none none solid; border-color:currentcolor currentcolor currentcolor rgb(204,204,204); padding:0in 0in 0in 6pt; margin-left:4.8pt; margin-right:0in">
<div>
<div>
<div>
<p class="x_MsoNormal"><span style="font-size:11pt">Purpose of </span>JDK-8341274 is to enable labels translation for custom attributes, it means other attributes than LineNumberTable, LocalVariableTable, LocalVariableTypeTable or CharacterRangeTable. It does
not include any plan to remodel existing architecture.<u></u><u></u></p>
<p class="x_MsoNormal"> <u></u><u></u></p>
<p class="x_MsoNormal">What exact use case related to the above-mentioned attributes are you struggling with?<u></u><u></u></p>
<p class="x_MsoNormal"> <u></u><u></u></p>
<p class="x_MsoNormal">Thanks,<u></u><u></u></p>
<p class="x_MsoNormal">Adam <u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<div id="x_m_773723447759013447m_3885507924158365885mail-editor-reference-message-container">
<div>
<div>
<div style="border-width:1pt medium medium; border-style:solid none none; padding:3pt 0in 0in; border-color:currentcolor">
<p class="x_MsoNormal" style="margin-bottom:12pt"><b><span style="color:black">From:
</span></b><span style="color:black">Rafael Winterhalter <<a href="mailto:rafael.wth@gmail.com" target="_blank">rafael.wth@gmail.com</a>><br>
<b>Date: </b>Monday, 11 November 2024 at 15:44<br>
<b>To: </b>Adam Sotona <<a href="mailto:adam.sotona@oracle.com" target="_blank">adam.sotona@oracle.com</a>><br>
<b>Subject: </b>Re: [External] : Re: Mapping byte code offsets in custom code attributes</span><u></u><u></u></p>
</div>
<div>
<div>
<p class="x_MsoNormal">Hello,<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal">As a goal of this conversation, I was hoping to give feedback on where I see limitations of the current API, something that resulted in JDK-8341274. As I wrote in previous emails on this list, I am evaluating it against a number of use
cases, all of which use ASM as of today. When I speak of migration, I mean that users of ASM would take the class file API into use instead. This is why I hoped that JDK-8341274 could be concluded by using this API to remodel these four info attributes, to
be consistent with TypeAnnotation and UninitializedVerificationTypeInfo. Clearly, if those attributes are using labels instead of BCIs, there should be a benefit of using labels exclusively? I had hoped that the Class File API could become as consistent as
ASM in this regard.<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal">I also understand that the mentioned info elements are streamlined with the code instruction API. But as the use of code generation has evolved upon ASM over many years, where attributes are not always generated at the same time as the
attributed code, but later. Rather, one notes down BCIs as labels in the generated code and writes the attribute upon completion. In some cases, such logic can be rewritten to fit the streamlined model. But sometimes this is really hard. Neither the class
file format, nor the class file API require that attributes on code are created simultaneously, so I was hoping that explicit BCIs could be removed from the public API altogether. Today, they only appear at four locations (LocalVariable, LocalVariableType,
CharacterRange and LineNumber) throughout the entire Class File API. Anywhere else, BCIs are resolved as labels. I think changing that would add to the Class File APIs quality, consistency and usability, when working with these attributes, similar to how it
is suggested to work with custom ones. I hoped I could argue that case before the API becomes final and this can no longer be changed.<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal">Patching line numbers is indeed supported, if one reiterates over the code, but I would not call this a seamless solution in contrast to just writing that attribute after completing the code attribute, if this is what is desired.<u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal"> <u></u><u></u></p>
</div>
<div>
<p class="x_MsoNormal">Thanks, Rafael<u></u><u></u></p>
</div>
</div>
<p class="x_MsoNormal"> <u></u><u></u></p>
<div>
<div>
<p class="x_MsoNormal">Am Mo., 11. Nov. 2024 um 14:38 Uhr schrieb Adam Sotona <<a href="mailto:adam.sotona@oracle.com" target="_blank">adam.sotona@oracle.com</a>>:<u></u><u></u></p>
</div>
<blockquote style="border-width:medium medium medium 1pt; border-style:none none none solid; padding:0in 0in 0in 6pt; margin:5pt 0in 5pt 4.8pt; border-color:currentcolor currentcolor currentcolor rgb(204,204,204)">
<div>
<div>
<div>
<p class="x_MsoNormal"><span style="font-size:11pt">Hi Rafael,</span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Im not sure what is goal of this discussion. Let me answer your questions below.</span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<div id="x_m_773723447759013447m_3885507924158365885m_5231128483693884018mail-editor-reference-message-container">
<div>
<div>
<div style="border-width:1pt medium medium; border-style:solid none none; padding:3pt 0in 0in; border-color:currentcolor">
<p class="x_MsoNormal" style="margin-bottom:12pt"><b><span style="color:black">From:
</span></b><span style="color:black">Rafael Winterhalter <<a href="mailto:rafael.wth@gmail.com" target="_blank">rafael.wth@gmail.com</a>></span><u></u><u></u></p>
</div>
<div>
<div>
<p class="x_MsoNormal"> <u></u><u></u></p>
</div>
<div>
<ul type="disc">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
What I do not understand is why this model should not be applied for LineNumberInfo, LocalVariableTypeInfo, LocalVariableInfo and CharacterRangeInfo?<u></u><u></u></li></ul>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">LocalVariable, LocalVariableType, CharacterRange and LineNumber are pseudo instructions (code elements). As such they are integral part of the CodeModel and they are streamed and transformed with the instructions.
</span>LineNumberInfo, LocalVariableTypeInfo, LocalVariableInfo are just inner structure data holders of the corresponding attributes and they serve only to specific use cases requesting the raw values.<u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<ul type="disc">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
Once a translation mechanism is in place, it should be straightforward to migrate?<u></u><u></u></li></ul>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Im not sure what migration do you have in mind.</span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<ul type="disc">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
What is the point of offering these attributes in a (public) API then, if not as ready for consumption?<u></u><u></u></li></ul>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">There are regular consumers of the API, like for example javap.</span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal" style="margin-left:0.5in"> <u></u><u></u></p>
</div>
<div>
<ul type="disc">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
As I see it: Without labels, I would need to implement a custom mapper, for example for writing a custom LineNumberTableAttribute,<u></u><u></u></li></ul>
<p class="x_MsoNormal"> <u></u><u></u></p>
<p class="x_MsoNormal">There are two aspects:<u></u><u></u></p>
<ol start="1" type="1">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
A custom LineNumberTable attribute mapper overriding the default one is not accepted by the API.<u></u><u></u></li><li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
Implementation of a custom attribute similar to LineNumberTable attribute is supported and after JDK-8341274 the support will improve.<u></u><u></u></li></ol>
<p class="x_MsoNormal"> <u></u><u></u></p>
<p class="x_MsoNormal"> <u></u><u></u></p>
<ul type="disc">
<li class="x_m_773723447759013447m3885507924158365885m5231128483693884018msolistparagraph">
if I wanted to patch line numbers after creating a method.<u></u><u></u></li></ul>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">Patching line numbers is seamlessly supported. CodeTransform can freely change, add, and remove line numbers.
</span><u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt"> </span><u></u><u></u></p>
</div>
</div>
<p class="x_MsoNormal"> <u></u><u></u></p>
<p class="x_MsoNormal"><span style="font-size:11pt">From the context I understand you call for indirect translation of each (currently inline) LocalVariable, LocalVariableType, CharacterRange and LineNumber into a Label-parametrized pseudo instructions + corresponding
LabelTargets. Such model has been rejected in the early Class-File API prototypes for significant negative performance impact.
</span><u></u><u></u></p>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</body>
</html>