[lld][InstrProf] Do not use cstring offset hashes in function order for compression

[SharonXSharon]

Using the hashes of cstring offset turned to have very minimal impact on the compressed size of large iOS apps. The patch removes that code, thus the cstring symbols will be treated the same way as other defined symbols in terms of hashes calculation.

[SharonXSharon]

@ellishg could you please review?

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[llvmbot]

@llvm/pr-subscribers-lld

@llvm/pr-subscribers-lld-macho

Author: None (SharonXSharon)

Changes

Using the hashes of cstring offset turned to have very minimal impact on the compressed size of large iOS apps. The patch removes that code, thus the cstring symbols will be treated the same way as other defined symbols in terms of hashes calculation.

---

Full diff: https://github.com/llvm/llvm-project/pull/113606.diff

1 Files Affected:

• (modified) lld/MachO/BPSectionOrderer.cpp (+1-4)

diff --git a/lld/MachO/BPSectionOrderer.cpp b/lld/MachO/BPSectionOrderer.cpp
index 07b44d48d65932..5db2242a35ef28 100644
--- a/lld/MachO/BPSectionOrderer.cpp
+++ b/lld/MachO/BPSectionOrderer.cpp
@@ -53,11 +53,8 @@ getRelocHash(const Reloc &reloc,
     kind = ("Section " + Twine(static_cast<uint8_t>(isec->kind()))).str();
   if (auto *sym = reloc.referent.dyn_cast<Symbol *>()) {
     kind += (" Symbol " + Twine(static_cast<uint8_t>(sym->kind()))).str();
-    if (auto *d = dyn_cast<Defined>(sym)) {
-      if (isa_and_nonnull<CStringInputSection>(isec))
-        return getRelocHash(kind, 0, isec->getOffset(d->value), reloc.addend);
+    if (auto *d = dyn_cast<Defined>(sym))
       return getRelocHash(kind, sectionIdx.value_or(0), d->value, reloc.addend);
-    }
   }
   return getRelocHash(kind, sectionIdx.value_or(0), 0, reloc.addend);
 }

[ellishg]

LGTM!

[github-actions]

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