[llvm-objcopy][NFC] Use StringSaver for --keep-global-symbols

Summary: Use StringSaver/BumpPtrAlloc when parsing lines from --keep-global-symbols files. This allows us to consistently use StringRef for driver options, which avoids copying the full strings for each object copied, as well as simplifies part of D57517.

Reviewers: jhenderson, evgeny777, alexshap

Subscribers: jakehehrlich

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57617

llvm-svn: 353068

llvm/tools/llvm-objcopy/CopyConfig.cpp

@@ -19,8 +19,8 @@
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Compression.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/StringSaver.h"
 #include <memory>
-#include <string>
 
 namespace llvm {
 namespace objcopy {
@@ -225,8 +225,10 @@ static const MachineInfo &getOutputFormatMachineInfo(StringRef Format) {
   return Iter->getValue();
 }
 
-static void addGlobalSymbolsFromFile(std::vector<std::string> &Symbols,
+static void addGlobalSymbolsFromFile(std::vector<StringRef> &Symbols,
+                                     BumpPtrAllocator &Alloc,
                                      StringRef Filename) {
+  StringSaver Saver(Alloc);
   SmallVector<StringRef, 16> Lines;
   auto BufOrErr = MemoryBuffer::getFile(Filename);
   if (!BufOrErr)
@@ -238,14 +240,15 @@ static void addGlobalSymbolsFromFile(std::vector<std::string> &Symbols,
     // it's not empty.
     auto TrimmedLine = Line.split('#').first.trim();
     if (!TrimmedLine.empty())
-      Symbols.push_back(TrimmedLine.str());
+      Symbols.push_back(Saver.save(TrimmedLine));
   }
 }
 
 // ParseObjcopyOptions returns the config and sets the input arguments. If a
 // help flag is set then ParseObjcopyOptions will print the help messege and
 // exit.
 DriverConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
+  DriverConfig DC;
   ObjcopyOptTable T;
   unsigned MissingArgumentIndex, MissingArgumentCount;
   llvm::opt::InputArgList InputArgs =
@@ -401,7 +404,8 @@ DriverConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
   for (auto Arg : InputArgs.filtered(OBJCOPY_keep_global_symbol))
     Config.SymbolsToKeepGlobal.push_back(Arg->getValue());
   for (auto Arg : InputArgs.filtered(OBJCOPY_keep_global_symbols))
-    addGlobalSymbolsFromFile(Config.SymbolsToKeepGlobal, Arg->getValue());
+    addGlobalSymbolsFromFile(Config.SymbolsToKeepGlobal, DC.Alloc,
+                             Arg->getValue());
   for (auto Arg : InputArgs.filtered(OBJCOPY_globalize_symbol))
     Config.SymbolsToGlobalize.push_back(Arg->getValue());
   for (auto Arg : InputArgs.filtered(OBJCOPY_weaken_symbol))
@@ -426,7 +430,6 @@ DriverConfig parseObjcopyOptions(ArrayRef<const char *> ArgsArr) {
   if (Config.DecompressDebugSections && !zlib::isAvailable())
     error("LLVM was not compiled with LLVM_ENABLE_ZLIB: cannot decompress.");
 
-  DriverConfig DC;
   DC.CopyConfigs.push_back(std::move(Config));
   return DC;
 }

llvm/tools/llvm-objcopy/CopyConfig.h

@@ -14,9 +14,9 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
 // Necessary for llvm::DebugCompressionType::None
 #include "llvm/Target/TargetOptions.h"
-#include <string>
 #include <vector>
 
 namespace llvm {
@@ -81,7 +81,7 @@ struct CopyConfig {
   std::vector<StringRef> SymbolsToRemove;
   std::vector<StringRef> SymbolsToWeaken;
   std::vector<StringRef> ToRemove;
-  std::vector<std::string> SymbolsToKeepGlobal;
+  std::vector<StringRef> SymbolsToKeepGlobal;
 
   // Map options
   StringMap<SectionRename> SectionsToRename;
@@ -112,6 +112,7 @@ struct CopyConfig {
 // will contain one or more CopyConfigs.
 struct DriverConfig {
   SmallVector<CopyConfig, 1> CopyConfigs;
+  BumpPtrAllocator Alloc;
 };
 
 // ParseObjcopyOptions returns the config and sets the input arguments. If a