[PATCH] D34800: [ELF] Remove unused synthetic sections from script commands

Petr Hosek via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Mon Jul 3 08:50:03 PDT 2017


This revision was automatically updated to reflect the committed changes.
Closed by commit rL307037: [ELF] Remove unused synthetic sections from script commands (authored by phosek).

Changed prior to commit:
  https://reviews.llvm.org/D34800?vs=104577&id=105090#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D34800

Files:
  lld/trunk/ELF/Writer.cpp
  lld/trunk/test/ELF/linkerscript/unused-synthetic.s


Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -1149,8 +1149,17 @@
     SS->Live = false;
     // If there are no other sections in the output section, remove it from the
     // output.
-    if (OS->Sections.empty())
+    if (OS->Sections.empty()) {
       V.erase(std::find(V.begin(), V.end(), OS));
+      // Also remove script commands matching the output section.
+      auto &Cmds = Script->Opt.Commands;
+      auto I = std::remove_if(Cmds.begin(), Cmds.end(), [&](BaseCommand *Cmd) {
+        if (auto *OSCmd = dyn_cast<OutputSectionCommand>(Cmd))
+          return OSCmd->Sec == OS;
+        return false;
+      });
+      Cmds.erase(I, Cmds.end());
+    }
   }
 }
 
Index: lld/trunk/test/ELF/linkerscript/unused-synthetic.s
===================================================================
--- lld/trunk/test/ELF/linkerscript/unused-synthetic.s
+++ lld/trunk/test/ELF/linkerscript/unused-synthetic.s
@@ -0,0 +1,18 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: echo "SECTIONS { \
+# RUN:    .got  : { *(.got) } \
+# RUN:    .plt  : { *(.plt) } \
+# RUN:    .text : { *(.text) } \
+# RUN:  }" > %t.script
+# RUN: ld.lld -shared -o %t.so --script %t.script %t.o
+
+# RUN: llvm-objdump -section-headers %t.so | FileCheck %s
+# CHECK-NOT:  .got
+# CHECK-NOT:  .plt
+# CHECK:      .text
+# CHECK-NEXT: .dynsym
+
+.global _start
+_start:
+  nop


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