Xcode 10, LLDB: Couldn't IRGen expression

Question

Using Xcode 10, when I stop my app using a breakpoint and try to print the content of an object in the Console, I obtain:

"Couldn't IRGen expression, no additional error"

However, I can see the value of the object in the Variables View panel.

How can I make it evaluate my expression instead?

I have the same issue with Xcode 10.1. May be it is related to break point in background thread? — Bill Chan, Oct 09 '18 at 08:57
@BillChan, I don't think so, In my sample I'm in the main thread. — asclepix, Oct 09 '18 at 08:59
Do you use Carthage? I find a article said if the framework is a binary not locally built. — Bill Chan, Oct 09 '18 at 09:14
@BillChan, I've just rebuilt every frameworks imported with Carthage and now even `po variable` works, thanks. (can you please post the link to the article you mentioned?) — asclepix, Oct 09 '18 at 09:33
This worked like a charm for me. https://stackoverflow.com/a/62417641/6342609 — Mithra Singam, Oct 20 '20 at 04:20

score 13 · Answer 1 · edited May 20 '22 at 00:59

13

In lldb as a workaround you can use:

fr v productVersion
fr v productBuild

since Xcode 10.2

v productVersion
v productBuild

which prints local variable type and address from current call stack frame.

Apple documentation for these kind of lldb capabilities: https://developer.apple.com/library/archive/documentation/General/Conceptual/lldb-guide/chapters/C5-Examining-The-Call-Stack.html

UPDATE: Another trick that seems to help is to set

edited May 20 '22 at 00:59

shim

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answered Oct 09 '18 at 09:35

Kamil.S

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Can you provide more information where you have found it and what it does? – milo Nov 06 '18 at 13:13
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@milo Added, hope that helps. – Kamil.S Nov 06 '18 at 14:32

score 8 · Answer 2 · edited Oct 27 '18 at 13:54

8

Thanks. I solved with rebuild carthage framework like imtx.me/archives/2719.html

carthage update --platform iOS --no-use-binaries

edited Oct 27 '18 at 13:54

James Eunson

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answered Oct 12 '18 at 12:12

Luigi Marino

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Please include the command for carthage that solved the problem in your answer – Kamil.S Oct 12 '18 at 13:15
There's no word about Carthage in question – vahotm Aug 16 '20 at 20:17

score 1 · Answer 3 · answered Nov 14 '18 at 16:28

1

I had defined as build system: "Legacy Build System", I changed it to "New Build System", then I build the project, and then I put it back as "Legacy Build System" and it worked again.

For to change the build mode: File->Workspace settings...->Build System

answered Nov 14 '18 at 16:28

Vins

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not working for my case. I have added two new targets also. – Pallavi Nikumbh Apr 11 '19 at 07:39

Genki · Answer 4 · 2020-02-05T23:11:57.433

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For my colleague, carthage update --platform iOS --no-use-binaries was working but it was not for me. When I removed the Carthage folder and reran the command, the po command started working . I'm not sure if it's related but I'm on macOS Catalina 10.15.3 and he is on Mojave. We both have Carthage version 0.34.0.

edited Feb 05 '20 at 23:11

answered Feb 05 '20 at 23:06

Genki

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infinity_coding7 · Answer 5 · 2020-09-08T03:04:35.857

My env: Xcode 11.6 and Xcode 12 Beta 6, carthage 0.34.0

In my case, my company wants me to make build of our app out of Xcode 12 beta and see what's broken. I did it and encounter another bug that crippled the carthage. I fixed it by following this answer in the same thread.

Then I switched back to Xcode 11.6, the error started to appear

error: Couldn't IRGen expression, no additional error

The variable inspector works normally but debug console is useless without print or po. It took me some time to search in SO before I realized this might be related to carthage. Then I updated all my dependencies using the following command

carthage bootstrap --platform iOS --no-use-binaries --cache-builds

Then the debug resume normal and I can use print/po again

Xcode 10, LLDB: Couldn't IRGen expression

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