[lld] [LTO][ELF][lld] Use unique saver in ELF bitcode symbol parsing (PR #106670)

[Mingming Liu via llvm-commits]

https://github.com/minglotus-6 created https://github.com/llvm/llvm-project/pull/106670

None

>From 7074440477eb9a689ff0210b2225c5a0e0b53c7d Mon Sep 17 00:00:00 2001
From: mingmingl <mingmingl at google.com>
Date: Thu, 29 Aug 2024 23:05:14 -0700
Subject: [PATCH] [lld][ELF]Use unique saver in bitcode symbol parsing

---
 lld/ELF/InputFiles.cpp                       | 24 ++++++++++++++++----
 lld/ELF/InputFiles.h                         | 10 ++++++++
 lld/include/lld/Common/CommonLinkerContext.h |  5 ++++
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/lld/ELF/InputFiles.cpp b/lld/ELF/InputFiles.cpp
index 7adc35f20984a5..ed946a91404088 100644
--- a/lld/ELF/InputFiles.cpp
+++ b/lld/ELF/InputFiles.cpp
@@ -1695,6 +1695,22 @@ static uint8_t getOsAbi(const Triple &t) {
   }
 }
 
+StringRef BitcodeFile::saved_symbol(const char *S) {
+  return unique_saver().save(S);
+}
+
+StringRef BitcodeFile::saved_symbol(StringRef S) {
+  return unique_saver().save(S);
+}
+
+StringRef BitcodeFile::saved_symbol(const Twine &S) {
+  return unique_saver().save(S);
+}
+
+StringRef BitcodeFile::saved_symbol(const std::string &S) {
+  return unique_saver().save(S);
+}
+
 BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
                          uint64_t offsetInArchive, bool lazy)
     : InputFile(BitcodeKind, mb) {
@@ -1712,8 +1728,8 @@ BitcodeFile::BitcodeFile(MemoryBufferRef mb, StringRef archiveName,
   // symbols later in the link stage). So we append file offset to make
   // filename unique.
   StringRef name = archiveName.empty()
-                       ? saver().save(path)
-                       : saver().save(archiveName + "(" + path::filename(path) +
+                       ? saved_symbol(path)
+                       : saved_symbol(archiveName + "(" + path::filename(path) +
                                       " at " + utostr(offsetInArchive) + ")");
   MemoryBufferRef mbref(mb.getBuffer(), name);
 
@@ -1745,7 +1761,7 @@ createBitcodeSymbol(Symbol *&sym, const std::vector<bool> &keptComdats,
   uint8_t visibility = mapVisibility(objSym.getVisibility());
 
   if (!sym)
-    sym = symtab.insert(saver().save(objSym.getName()));
+    sym = symtab.insert(unique_saver().save(objSym.getName()));
 
   int c = objSym.getComdatIndex();
   if (objSym.isUndefined() || (c != -1 && !keptComdats[c])) {
@@ -1797,7 +1813,7 @@ void BitcodeFile::parseLazy() {
   symbols = std::make_unique<Symbol *[]>(numSymbols);
   for (auto [i, irSym] : llvm::enumerate(obj->symbols()))
     if (!irSym.isUndefined()) {
-      auto *sym = symtab.insert(saver().save(irSym.getName()));
+      auto *sym = symtab.insert(saved_symbol(irSym.getName()));
       sym->resolve(LazySymbol{*this});
       symbols[i] = sym;
     }
diff --git a/lld/ELF/InputFiles.h b/lld/ELF/InputFiles.h
index b0a74877d0aaeb..28c4c1a1f92962 100644
--- a/lld/ELF/InputFiles.h
+++ b/lld/ELF/InputFiles.h
@@ -9,6 +9,8 @@
 #ifndef LLD_ELF_INPUT_FILES_H
 #define LLD_ELF_INPUT_FILES_H
 
+#include <string>
+
 #include "Config.h"
 #include "Symbols.h"
 #include "lld/Common/ErrorHandler.h"
@@ -23,6 +25,8 @@
 namespace llvm {
 struct DILineInfo;
 class TarWriter;
+class StringRef;
+class Twine;
 namespace lto {
 class InputFile;
 }
@@ -335,6 +339,12 @@ class BitcodeFile : public InputFile {
   void postParse();
   std::unique_ptr<llvm::lto::InputFile> obj;
   std::vector<bool> keptComdats;
+
+private:
+  StringRef saved_symbol(const char *S);
+  StringRef saved_symbol(StringRef S);
+  StringRef saved_symbol(const Twine &S);
+  StringRef saved_symbol(const std::string &S);
 };
 
 // .so file.
diff --git a/lld/include/lld/Common/CommonLinkerContext.h b/lld/include/lld/Common/CommonLinkerContext.h
index 0627bbdc8bd877..0c5349fbf16cd1 100644
--- a/lld/include/lld/Common/CommonLinkerContext.h
+++ b/lld/include/lld/Common/CommonLinkerContext.h
@@ -38,6 +38,7 @@ class CommonLinkerContext {
 
   llvm::BumpPtrAllocator bAlloc;
   llvm::StringSaver saver{bAlloc};
+  llvm::UniqueStringSaver unique_saver{bAlloc};
   llvm::DenseMap<void *, SpecificAllocBase *> instances;
 
   ErrorHandler e;
@@ -56,6 +57,10 @@ bool hasContext();
 
 inline llvm::StringSaver &saver() { return context().saver; }
 inline llvm::BumpPtrAllocator &bAlloc() { return context().bAlloc; }
+
+inline llvm::UniqueStringSaver &unique_saver() {
+  return context().unique_saver;
+}
 } // namespace lld
 
 #endif