[lld] r260724 - ELF: Remove use of MapVector from LinkerScript.

[Rui Ueyama via llvm-commits]

Author: ruiu
Date: Fri Feb 12 14:41:43 2016
New Revision: 260724

URL: http://llvm.org/viewvc/llvm-project?rev=260724&view=rev
Log:
ELF: Remove use of MapVector from LinkerScript.

We don't have to use a MapVector here. Instead, just std::vector suffices.

Modified:
    lld/trunk/ELF/Driver.cpp
    lld/trunk/ELF/LinkerScript.cpp
    lld/trunk/ELF/LinkerScript.h

Modified: lld/trunk/ELF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Driver.cpp?rev=260724&r1=260723&r2=260724&view=diff
==============================================================================
--- lld/trunk/ELF/Driver.cpp (original)
+++ lld/trunk/ELF/Driver.cpp Fri Feb 12 14:41:43 2016
@@ -296,7 +296,6 @@ template <class ELFT> void LinkerDriver:
   SymbolTable<ELFT> Symtab;
   std::unique_ptr<TargetInfo> TI(createTarget());
   Target = TI.get();
-  Script->finalize();
 
   if (!Config->Shared) {
     // Add entry symbol.

Modified: lld/trunk/ELF/LinkerScript.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.cpp?rev=260724&r1=260723&r2=260724&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.cpp (original)
+++ lld/trunk/ELF/LinkerScript.cpp Fri Feb 12 14:41:43 2016
@@ -28,27 +28,22 @@ using namespace lld::elf2;
 
 LinkerScript *elf2::Script;
 
-void LinkerScript::finalize() {
-  for (const std::pair<StringRef, std::vector<StringRef>> &P : Sections)
-    for (StringRef S : P.second)
-      RevSections[S] = P.first;
-}
-
 StringRef LinkerScript::getOutputSection(StringRef S) {
-  return RevSections.lookup(S);
+  return Sections.lookup(S);
 }
 
 bool LinkerScript::isDiscarded(StringRef S) {
-  return RevSections.lookup(S) == "/DISCARD/";
+  return Sections.lookup(S) == "/DISCARD/";
 }
 
+// A compartor to sort output sections. Returns -1 or 1 if both
+// A and B are mentioned in linker scripts. Otherwise, returns 0
+// to use the default rule which is implemented in Writer.cpp.
 int LinkerScript::compareSections(StringRef A, StringRef B) {
-  auto I = Sections.find(A);
-  auto E = Sections.end();
-  if (I == E)
-    return 0;
-  auto J = Sections.find(B);
-  if (J == E)
+  auto E = SectionOrder.end();
+  auto I = std::find(SectionOrder.begin(), E, A);
+  auto J = std::find(SectionOrder.begin(), E, B);
+  if (I == E || J == E)
     return 0;
   return I < J ? -1 : 1;
 }
@@ -349,14 +344,15 @@ void ScriptParser::readSections() {
 }
 
 void ScriptParser::readOutputSectionDescription() {
-  std::vector<StringRef> &V = Script->Sections[next()];
+  StringRef OutSec = next();
+  Script->SectionOrder.push_back(OutSec);
   expect(":");
   expect("{");
   while (!Error && !skip("}")) {
     next(); // Skip input file name.
     expect("(");
     while (!Error && !skip(")"))
-      V.push_back(next());
+      Script->Sections[next()] = OutSec;
   }
 }
 

Modified: lld/trunk/ELF/LinkerScript.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/LinkerScript.h?rev=260724&r1=260723&r2=260724&view=diff
==============================================================================
--- lld/trunk/ELF/LinkerScript.h (original)
+++ lld/trunk/ELF/LinkerScript.h Fri Feb 12 14:41:43 2016
@@ -32,15 +32,14 @@ public:
   StringRef getOutputSection(StringRef InputSection);
   bool isDiscarded(StringRef InputSection);
   int compareSections(StringRef A, StringRef B);
-  void finalize();
 
 private:
-  // Map for SECTIONS command. The key is output section name
-  // and a value is a list of input section names.
-  llvm::MapVector<StringRef, std::vector<StringRef>> Sections;
+  // A map for SECTIONS command. The key is input section name
+  // and the value is the corresponding output section name.
+  llvm::DenseMap<StringRef, StringRef> Sections;
 
-  // Inverse map of Sections.
-  llvm::DenseMap<StringRef, StringRef> RevSections;
+  // Output sections are sorted by this order.
+  std::vector<StringRef> SectionOrder;
 
   llvm::BumpPtrAllocator Alloc;
 };