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<p class="MsoNormal">If you use the Clang options `-emit-llvm -S` it will produce a .ll file containing the textual IR produced by Clang.<o:p></o:p></p>
<p class="MsoNormal">Use this to compile a simple C example using a VLA and it should give you a model of the IR and metadata you would need to produce. I used a source something like this:<o:p></o:p></p>
<p class="MsoNormal"> int foo(int s) {<o:p></o:p></p>
<p class="MsoNormal"> int a[s];<o:p></o:p></p>
<p class="MsoNormal"> int i;<o:p></o:p></p>
<p class="MsoNormal"> for (i = 0; i < s; ++i)<o:p></o:p></p>
<p class="MsoNormal"> a[i] = s;<o:p></o:p></p>
<p class="MsoNormal"> return 0;<o:p></o:p></p>
<p class="MsoNormal"> }<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">What I see is a DILocalVariable for “a” that has a type that is a DICompositeType with DW_TAG_array_type, and the `elements` array of the DICompositeType points to a DISubrange whose `count` points to a DILocalVariable that is the upper
bound.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The resulting DWARF looks okay to me, although I admit I haven’t actually tried running gdb on it to make sure.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I haven’t looked up the DIBuilder APIs, if that’s what you are looking for, but based on what you said, it sounds like you would be able to work that out yourself.<o:p></o:p></p>
<p class="MsoNormal">HTH,<o:p></o:p></p>
<p class="MsoNormal">--paulr<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Levo DeLellis via llvm-dev<br>
<b>Sent:</b> Thursday, February 13, 2020 1:03 PM<br>
<b>To:</b> llvm-dev@lists.llvm.org<br>
<b>Subject:</b> [llvm-dev] Have the debugger show an away with a dynamic size?<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Hi. I searched and the closest thing I could find was this <a href="http://lists.llvm.org/pipermail/llvm-dev/2018-February/121348.html">
http://lists.llvm.org/pipermail/llvm-dev/2018-February/121348.html</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Currently a known sized array looks and debugs as expected. I use llvm.dbg.declare with DICompositeType tag: DW_TAG_array_type and the size field. In my language arrays are always passed around with a pointer and size pair. I'd like debugging
to show up as nicely instead of a pointer addr with no information about the elements. How would I do this? I don't use the C API, I output llvm-ir directly. I was hoping I can call
<span class="gmail-pre"><span style="font-size:10.0pt;font-family:"Courier New"">llvm.dbg.declare/addr/value to specify the pointer, name and size of the variable but I really have no idea how to pass the size to the debugger.</span></span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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