Improve readability of "undefined reference" message

[DeanSturtevant1]

The current message implies a command line flag caused an undefined reference. This of course is wrong and causes confusion. The message now more accurately reflects the true state of affairs.

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[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-elf

Author: None (DeanSturtevant1)

Changes

The current message implies a command line flag caused an undefined reference. This of course is wrong and causes confusion. The message now more accurately reflects the true state of affairs.

---

Full diff: https://github.com/llvm/llvm-project/pull/82671.diff

1 Files Affected:

• (modified) lld/ELF/Writer.cpp (+3-2)

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 0bbf43ddf694aa..cf8825296213b2 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -2057,8 +2057,9 @@ template <class ELFT> void Writer<ELFT>::finalizeSections() {
           if (sym->dsoDefined)
             continue;
           if (sym->isUndefined() && !sym->isWeak()) {
-            diagnose("undefined reference due to --no-allow-shlib-undefined: " +
-                     toString(*sym) + "\n>>> referenced by " + toString(file));
+            diagnose("undefined reference: " +
+                     toString(*sym) + "\n>>> referenced by " + toString(file) +
+                     " (disallowed by --no-allow-shlib-undefined)");
           } else if (sym->isDefined() && sym->computeBinding() == STB_LOCAL) {
             diagnose("non-exported symbol '" + toString(*sym) + "' in '" +
                      toString(sym->file) + "' is referenced by DSO '" +

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✅ With the latest revision this PR passed the C/C++ code formatter.

[dwblaikie]

The "due to" wording came from here: https://reviews.llvm.org/D129790 not sure if that came out of any particular discussion

[MaskRay]

The new message looks good to me, but I want to check with folks who have reviewed/worked on previous diagnostic changes.

[igorkudrin]

LGTM. The new wording seems clearer. Thanks!

[smithp35]

LGTM too

[DeanSturtevant1]

Looks like I don't have an option to merge this pull request. Would someone do it for me? Thanks!

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