commit 0702c4e86eb61dc2db22bb51525fb2edb008af4d
author George Rimar <grimar@accesssoftek.com> Fri Jul 29 15:32:46 2016 +0000
committer George Rimar <grimar@accesssoftek.com> Fri Jul 29 15:32:46 2016 +0000
tree 48b57c1b2af5daad4ac742c8b7c40da242a5e913
parent b20c34edf378af5fce9bf504126999df67407bfe

[ELF] - Linkerscript: Implemented SORT command.

When the SORT keyword is used, the linker will sort the files or sections into ascending order by name before placing them in the output file.
It is used in FreeBSD script:
https://svnweb.freebsd.org/base/head/sys/conf/ldscript.amd64?revision=284870&view=markup#l139

This is PR28689.

Differential revision: https://reviews.llvm.org/D22749

llvm-svn: 277153

lld/ELF/LinkerScript.cpp

diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 097375a..ed47c74 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -132,11 +132,18 @@
 }
 
 template <class ELFT>
+static bool compareByName(InputSectionBase<ELFT> *A,
+                          InputSectionBase<ELFT> *B) {
+  return A->getSectionName() < B->getSectionName();
+}
+
+template <class ELFT>
 std::vector<OutputSectionBase<ELFT> *>
 LinkerScript<ELFT>::createSections(OutputSectionFactory<ELFT> &Factory) {
   std::vector<OutputSectionBase<ELFT> *> Ret;
 
   for (auto &P : getSectionMap()) {
+    std::vector<InputSectionBase<ELFT> *> Sections;
     StringRef OutputName = P.first;
     const InputSectionDescription *I = P.second;
     for (InputSectionBase<ELFT> *S : getInputSections(I)) {
@@ -145,8 +152,12 @@
         reportDiscarded(S);
         continue;
       }
-      addSection(Factory, Ret, S, OutputName);
+      Sections.push_back(S);
     }
+    if (I->Sort)
+      std::stable_sort(Sections.begin(), Sections.end(), compareByName<ELFT>);
+    for (InputSectionBase<ELFT> *S : Sections)
+      addSection(Factory, Ret, S, OutputName);
   }
 
   // Add all other input sections, which are not listed in script.
@@ -444,6 +455,7 @@
   std::vector<uint8_t> readOutputSectionFiller();
   std::vector<StringRef> readOutputSectionPhdrs();
   std::unique_ptr<InputSectionDescription> readInputSectionDescription();
+  void readInputFilePattern(InputSectionDescription *InCmd, bool Keep);
   void readInputSectionRules(InputSectionDescription *InCmd, bool Keep);
   unsigned readPhdrType();
   void readProvide(bool Hidden);
@@ -674,7 +686,17 @@
       .Default(-1);
 }
 
-void ScriptParser::readInputSectionRules(InputSectionDescription *InCmd, bool Keep) {
+void ScriptParser::readInputFilePattern(InputSectionDescription *InCmd,
+                                        bool Keep) {
+  while (!Error && !skip(")")) {
+    if (Keep)
+      Opt.KeptSections.push_back(peek());
+    InCmd->SectionPatterns.push_back(next());
+  }
+}
+
+void ScriptParser::readInputSectionRules(InputSectionDescription *InCmd,
+                                         bool Keep) {
   InCmd->FilePattern = next();
   expect("(");
 
@@ -684,11 +706,15 @@
       InCmd->ExcludedFiles.push_back(next());
   }
 
-  while (!Error && !skip(")")) {
-    if (Keep)
-      Opt.KeptSections.push_back(peek());
-    InCmd->SectionPatterns.push_back(next());
+  if (skip("SORT")) {
+    expect("(");
+    InCmd->Sort = true;
+    readInputFilePattern(InCmd, Keep);
+    expect(")");
+    return;
   }
+
+  readInputFilePattern(InCmd, Keep);
 }
 
 std::unique_ptr<InputSectionDescription>