[lld] r262366 - [ELF] - do not create special symbols when creating relocatable output
George Rimar via llvm-commits
llvm-commits at lists.llvm.org
Tue Mar 1 11:12:35 PST 2016
Author: grimar
Date: Tue Mar 1 13:12:35 2016
New Revision: 262366
URL: http://llvm.org/viewvc/llvm-project?rev=262366&view=rev
Log:
[ELF] - do not create special symbols when creating relocatable output
__start_/__end_ <section-name> symbols and other specials like:
preinit_array_start/end
init_array_start/end
fini_array_start/end
should not be created by linker when creating relocatable files.
Differential revision: http://reviews.llvm.org/D17774
Added:
lld/trunk/test/ELF/relocatable-symbols.s
Modified:
lld/trunk/ELF/Writer.cpp
Modified: lld/trunk/ELF/Writer.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=262366&r1=262365&r2=262366&view=diff
==============================================================================
--- lld/trunk/ELF/Writer.cpp (original)
+++ lld/trunk/ELF/Writer.cpp Tue Mar 1 13:12:35 2016
@@ -1001,9 +1001,11 @@ template <class ELFT> bool Writer<ELFT>:
// The linker needs to define SECNAME_start, SECNAME_end and SECNAME_stop
// symbols for sections, so that the runtime can get the start and end
// addresses of each section by section name. Add such symbols.
- addStartEndSymbols();
- for (OutputSectionBase<ELFT> *Sec : RegularSections)
- addStartStopSymbols(Sec);
+ if (!Config->Relocatable) {
+ addStartEndSymbols();
+ for (OutputSectionBase<ELFT> *Sec : RegularSections)
+ addStartStopSymbols(Sec);
+ }
if (isOutputDynamic())
Symtab.addSynthetic("_DYNAMIC", *Out<ELFT>::Dynamic, 0, STV_HIDDEN);
Added: lld/trunk/test/ELF/relocatable-symbols.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/relocatable-symbols.s?rev=262366&view=auto
==============================================================================
--- lld/trunk/test/ELF/relocatable-symbols.s (added)
+++ lld/trunk/test/ELF/relocatable-symbols.s Tue Mar 1 13:12:35 2016
@@ -0,0 +1,183 @@
+# REQUIRES: x86
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t
+# RUN: ld.lld -r %t -o %tout
+# RUN: llvm-objdump -d %tout | FileCheck -check-prefix=DISASM %s
+# RUN: llvm-readobj -symbols -r %tout | FileCheck -check-prefix=SYMBOL %s
+
+# DISASM: _start:
+# DISASM-NEXT: 0: {{.*}} callq 0
+# DISASM-NEXT: 5: {{.*}} callq 0
+# DISASM-NEXT: a: {{.*}} callq 0
+# DISASM-NEXT: f: {{.*}} callq 0
+# DISASM-NEXT: 14: {{.*}} callq 0
+# DISASM-NEXT: 19: {{.*}} callq 0
+# DISASM-NEXT: 1e: {{.*}} callq 0
+# DISASM-NEXT: 23: {{.*}} callq 0
+# DISASM-NEXT: 28: {{.*}} callq 0
+# DISASM-NEXT: 2d: {{.*}} callq 0
+# DISASM-NEXT: 32: {{.*}} callq 0
+# DISASM-NEXT: 37: {{.*}} callq 0
+# DISASM-NEXT: Disassembly of section foo:
+# DISASM-NEXT: foo:
+# DISASM-NEXT: 0: 90 nop
+# DISASM-NEXT: 1: 90 nop
+# DISASM-NEXT: 2: 90 nop
+# DISASM-NEXT: Disassembly of section bar:
+# DISASM-NEXT: bar:
+# DISASM-NEXT: 0: 90 nop
+# DISASM-NEXT: 1: 90 nop
+# DISASM-NEXT: 2: 90 nop
+
+# SYMBOL: Relocations [
+# SYMBOL-NEXT: Section ({{.*}}) .rela.text {
+# SYMBOL-NEXT: 0x1 R_X86_64_PC32 __start_foo 0x0
+# SYMBOL-NEXT: 0x6 R_X86_64_PC32 __stop_foo 0x0
+# SYMBOL-NEXT: 0xB R_X86_64_PC32 __start_bar 0x0
+# SYMBOL-NEXT: 0x10 R_X86_64_PC32 __stop_bar 0x0
+# SYMBOL-NEXT: 0x15 R_X86_64_PC32 __start_doo 0x0
+# SYMBOL-NEXT: 0x1A R_X86_64_PC32 __stop_doo 0x0
+# SYMBOL-NEXT: 0x1F R_X86_64_PC32 __preinit_array_start 0x0
+# SYMBOL-NEXT: 0x24 R_X86_64_PC32 __preinit_array_end 0x0
+# SYMBOL-NEXT: 0x29 R_X86_64_PC32 __init_array_start 0x0
+# SYMBOL-NEXT: 0x2E R_X86_64_PC32 __init_array_end 0x0
+# SYMBOL-NEXT: 0x33 R_X86_64_PC32 __fini_array_start 0x0
+# SYMBOL-NEXT: 0x38 R_X86_64_PC32 __fini_array_end 0x0
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: ]
+# SYMBOL: Symbol {
+# SYMBOL: Name: __fini_array_end
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __fini_array_start
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __init_array_end
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __init_array_start
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __preinit_array_end
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __preinit_array_start
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __start_bar
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __start_doo
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __start_foo
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __stop_bar
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __stop_doo
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+# SYMBOL-NEXT: Symbol {
+# SYMBOL-NEXT: Name: __stop_foo
+# SYMBOL-NEXT: Value: 0x0
+# SYMBOL-NEXT: Size: 0
+# SYMBOL-NEXT: Binding: Global
+# SYMBOL-NEXT: Type: None
+# SYMBOL-NEXT: Other: 0
+# SYMBOL-NEXT: Section: Undefined
+# SYMBOL-NEXT: }
+
+.global _start
+.text
+_start:
+ call __start_foo
+ call __stop_foo
+
+ call __start_bar
+ call __stop_bar
+
+ call __start_doo
+ call __stop_doo
+
+ call __preinit_array_start
+ call __preinit_array_end
+ call __init_array_start
+ call __init_array_end
+ call __fini_array_start
+ call __fini_array_end
+
+.section foo,"ax"
+ nop
+ nop
+ nop
+
+.section bar,"ax"
+ nop
+ nop
+ nop
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