[PATCH] D93711: [lld/mac] Don't add names of unreferenced symbols to string table

[Nico Weber via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG57ffbe020af6: glld/mac] Don't add names of unreferenced symbols to string table (authored by thakis).
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D93711/new/

https://reviews.llvm.org/D93711

Files:
  lld/MachO/SyntheticSections.cpp
  lld/test/MachO/symtab.s


Index: lld/test/MachO/symtab.s
===================================================================
--- lld/test/MachO/symtab.s
+++ lld/test/MachO/symtab.s
@@ -86,17 +86,19 @@
 # CHECK-NEXT:   iundefsym: 5
 # CHECK-NEXT:   nundefsym: 2
 
-## Verify that the first entry in the StringTable is a space.
+## Verify that the first entry in the StringTable is a space, and that
+## unreferenced symbols aren't emitted.
 # RUN: obj2yaml %t/test | FileCheck %s --check-prefix=YAML
 # YAML:      StringTable:
 # YAML-NEXT: ' '
+# YAML-NOT: _unreferenced
 
 #--- libfoo.s
 .globl _dynamic
 _dynamic:
 
 #--- test.s
-.globl _main, _external, _external_weak
+.globl _main, _external, _external_weak, _unreferenced
 
 .data
 _external:
Index: lld/MachO/SyntheticSections.cpp
===================================================================
--- lld/MachO/SyntheticSections.cpp
+++ lld/MachO/SyntheticSections.cpp
@@ -694,6 +694,11 @@
 }
 
 void SymtabSection::finalizeContents() {
+  auto addSymbol = [&](std::vector<SymtabEntry> &symbols, Symbol *sym) {
+    uint32_t strx = stringTableSection.addString(sym->getName());
+    symbols.push_back({sym, strx});
+  };
+
   // Local symbols aren't in the SymbolTable, so we walk the list of object
   // files to gather them.
   for (InputFile *file : inputFiles) {
@@ -702,10 +707,8 @@
         // TODO: when we implement -dead_strip, we should filter out symbols
         // that belong to dead sections.
         if (auto *defined = dyn_cast<Defined>(sym)) {
-          if (!defined->isExternal()) {
-            uint32_t strx = stringTableSection.addString(sym->getName());
-            localSymbols.push_back({sym, strx});
-          }
+          if (!defined->isExternal())
+            addSymbol(localSymbols, sym);
         }
       }
     }
@@ -713,19 +716,16 @@
 
   // __dyld_private is a local symbol too. It's linker-created and doesn't
   // exist in any object file.
-  if (Defined* dyldPrivate = in.stubHelper->dyldPrivate) {
-    uint32_t strx = stringTableSection.addString(dyldPrivate->getName());
-    localSymbols.push_back({dyldPrivate, strx});
-  }
+  if (Defined* dyldPrivate = in.stubHelper->dyldPrivate)
+    addSymbol(localSymbols, dyldPrivate);
 
   for (Symbol *sym : symtab->getSymbols()) {
-    uint32_t strx = stringTableSection.addString(sym->getName());
     if (auto *defined = dyn_cast<Defined>(sym)) {
       assert(defined->isExternal());
-      externalSymbols.push_back({sym, strx});
+      addSymbol(externalSymbols, sym);
     } else if (auto *dysym = dyn_cast<DylibSymbol>(sym)) {
       if (dysym->isReferenced())
-        undefinedSymbols.push_back({sym, strx});
+        addSymbol(undefinedSymbols, sym);
     }
   }
 


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