[PATCH] D30193: [ELF] - Scan lazy linkerscipt symbols early.

[George Rimar via Phabricator via llvm-commits]

grimar updated this revision to Diff 89214.
grimar added a comment.

- Simplified testcase.


https://reviews.llvm.org/D30193

Files:
  ELF/Driver.cpp
  ELF/LinkerScript.cpp
  ELF/LinkerScript.h
  test/ELF/linkerscript/Inputs/lazy-symbols.s
  test/ELF/linkerscript/lazy-symbols.s


Index: test/ELF/linkerscript/lazy-symbols.s
===================================================================
--- test/ELF/linkerscript/lazy-symbols.s
+++ test/ELF/linkerscript/lazy-symbols.s
@@ -0,0 +1,10 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %S/Inputs/lazy-symbols.s -o %t1
+# RUN: llvm-ar rcs %tar %t1
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t2
+# RUN: echo "foo = 1;" > %t.script
+# RUN: ld.lld %t2 %tar --script %t.script -o %tout
+# RUN: llvm-readobj -symbols %tout | FileCheck %s
+
+# CHECK: Name: foo
+# CHECK-NEXT: Value: 0x1
Index: test/ELF/linkerscript/Inputs/lazy-symbols.s
===================================================================
--- test/ELF/linkerscript/Inputs/lazy-symbols.s
+++ test/ELF/linkerscript/Inputs/lazy-symbols.s
@@ -0,0 +1,7 @@
+.globl foo
+foo:
+ .long .Linfo_string
+ 
+.section .debug_str,"MS", at progbits,1
+.Linfo_string:
+  .asciz "foo"
Index: ELF/LinkerScript.h
===================================================================
--- ELF/LinkerScript.h
+++ ELF/LinkerScript.h
@@ -247,6 +247,7 @@
   LinkerScript();
   ~LinkerScript();
 
+  void fetchLazySymbols();
   void processCommands(OutputSectionFactory<ELFT> &Factory);
   void addOrphanSections(OutputSectionFactory<ELFT> &Factory);
   void removeEmptyCommands();
Index: ELF/LinkerScript.cpp
===================================================================
--- ELF/LinkerScript.cpp
+++ ELF/LinkerScript.cpp
@@ -321,6 +321,17 @@
   return Ret;
 }
 
+// Script can contain assignments to lazy symbols. In that case
+// we should scan such symbols early to fetch objects from archives
+// and create input sections.
+template <class ELFT> void LinkerScript<ELFT>::fetchLazySymbols() {
+  for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
+    if (auto *Cmd = dyn_cast<SymbolAssignment>(Base.get()))
+      if (SymbolBody *Sym = Symtab<ELFT>::X->find(Cmd->Name))
+        if (Sym->isLazy())
+          addSymbol(Cmd);
+}
+
 template <class ELFT>
 void LinkerScript<ELFT>::processCommands(OutputSectionFactory<ELFT> &Factory) {
   for (unsigned I = 0; I < Opt.Commands.size(); ++I) {
Index: ELF/Driver.cpp
===================================================================
--- ELF/Driver.cpp
+++ ELF/Driver.cpp
@@ -839,6 +839,8 @@
   for (auto *Arg : Args.filtered(OPT_wrap))
     Symtab.wrap(Arg->getValue());
 
+  Script<ELFT>::X->fetchLazySymbols();
+
   // Now that we have a complete list of input files.
   // Beyond this point, no new files are added.
   // Aggregate all input sections into one place.


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