[lld] r234130 - Strip .strtab and .symtab when --strip-all is used.

[Davide Italiano]

Author: davide
Date: Sun Apr  5 17:47:54 2015
New Revision: 234130

URL: http://llvm.org/viewvc/llvm-project?rev=234130&view=rev
Log:
Strip .strtab and .symtab when --strip-all is used.
This matches other linkers behaviour. Moreover, there's really
no need to keep them around.

Reported by: Rafael Avila de Espindola

PR:		22890

Modified:
    lld/trunk/lib/ReaderWriter/ELF/OutputELFWriter.h
    lld/trunk/test/elf/strip-all.test

Modified: lld/trunk/lib/ReaderWriter/ELF/OutputELFWriter.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/OutputELFWriter.h?rev=234130&r1=234129&r2=234130&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/OutputELFWriter.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/OutputELFWriter.h Sun Apr  5 17:47:54 2015
@@ -319,9 +319,11 @@ void OutputELFWriter<ELFT>::buildAtomToA
     _atomToAddressMap[atom->_atom] = atom->_virtualAddr;
 
   // Set the total number of atoms in the symbol table, so that appropriate
-  // resizing of the string table can be done
-  _symtab->setNumEntries(totalDefinedAtoms + totalAbsAtoms +
-                         totalUndefinedAtoms);
+  // resizing of the string table can be done.
+  // There's no such thing as symbol table if we're stripping all the symbols
+  if (!_ctx.stripSymbols())
+    _symtab->setNumEntries(totalDefinedAtoms + totalAbsAtoms +
+                           totalUndefinedAtoms);
 }
 
 template<class ELFT>
@@ -395,18 +397,23 @@ template <class ELFT> void OutputELFWrit
   _layout.setHeader(_elfHeader.get());
   _layout.setProgramHeader(_programHeader.get());
 
-  _symtab = std::move(this->createSymbolTable());
-  _strtab.reset(new (_alloc) StringTable<ELFT>(
-      _ctx, ".strtab", TargetLayout<ELFT>::ORDER_STRING_TABLE));
+  // Don't create .symtab and .strtab sections if we're going to
+  // strip all the symbols.
+  if (!_ctx.stripSymbols()) {
+    _symtab = std::move(this->createSymbolTable());
+    _strtab.reset(new (_alloc) StringTable<ELFT>(
+        _ctx, ".strtab", TargetLayout<ELFT>::ORDER_STRING_TABLE));
+    _layout.addSection(_symtab.get());
+    _layout.addSection(_strtab.get());
+    _symtab->setStringSection(_strtab.get());
+  }
+
   _shstrtab.reset(new (_alloc) StringTable<ELFT>(
       _ctx, ".shstrtab", TargetLayout<ELFT>::ORDER_SECTION_STRINGS));
   _shdrtab.reset(new (_alloc) SectionHeader<ELFT>(
       _ctx, TargetLayout<ELFT>::ORDER_SECTION_HEADERS));
-  _layout.addSection(_symtab.get());
-  _layout.addSection(_strtab.get());
   _layout.addSection(_shstrtab.get());
   _shdrtab->setStringSection(_shstrtab.get());
-  _symtab->setStringSection(_strtab.get());
   _layout.addSection(_shdrtab.get());
 
   for (auto sec : _layout.sections()) {

Modified: lld/trunk/test/elf/strip-all.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/strip-all.test?rev=234130&r1=234129&r2=234130&view=diff
==============================================================================
--- lld/trunk/test/elf/strip-all.test (original)
+++ lld/trunk/test/elf/strip-all.test Sun Apr  5 17:47:54 2015
@@ -1,5 +1,5 @@
-# Tests the --strip-all (-s) flag. We expect the symbol table to not contain
-# any symbol in the output file.
+# Tests the --strip-all (-s) flag.
+# We expect that .symtab and .strtab are stripped from the final executable.
 #
 # The following code was used to generate the object.
 # $ clang -c blah.c -o blah
@@ -20,9 +20,11 @@
 
 #RUN: yaml2obj -format=elf %s -o=%t.o
 #RUN: lld -flavor gnu -target x86_64 %t.o -e=main --strip-all -o %t1
-#RUN: llvm-readobj -dt %t1 | FileCheck -check-prefix CHECKSYMS %s
+#RUN: llvm-objdump -section-headers %t1 | FileCheck %s
 
-#CHECKSYMS: @
+#CHECK:  14 .shstrtab     0000007d 0000000000000000
+#CHECK-NOT:  15 .symtab       00000198 0000000000000000
+#CHECK-NOT:  16 .strtab       000000e4 0000000000000000
 
 ---
 FileHeader: