[lld] r233051 - [ELF/X86_64] Fix handling of R_X86_64_GOTTPOFF relocation.

[Davide Italiano]

Author: davide
Date: Tue Mar 24 01:22:45 2015
New Revision: 233051

URL: http://llvm.org/viewvc/llvm-project?rev=233051&view=rev
Log:
[ELF/X86_64] Fix handling of R_X86_64_GOTTPOFF relocation.

The aforementioned relocation generate a GOT entry with a
R_X86_64_TPOFF64. The new relocation is processed at startup
time by the loader. lld didn't generate the outstanding relocation,
now it does. This bug was found while trying to link ls(1) on FreeBSD.

Simplified repro:
#include <stdio.h>
#include <wchar.h>
#include <wctype.h>

int
main(void)
{
    wchar_t wc = 98;
    if (!iswprint(wc))
        printf("blah\n");
    else
        printf("foo\n");
    return (0);
}

which incorrectly outputs "blah" when linked with lld before this patch.

Added:
    lld/trunk/test/elf/gottpoff.test
Modified:
    lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64LinkingContext.h

Modified: lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64LinkingContext.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64LinkingContext.h?rev=233051&r1=233050&r2=233051&view=diff
==============================================================================
--- lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64LinkingContext.h (original)
+++ lld/trunk/lib/ReaderWriter/ELF/X86_64/X86_64LinkingContext.h Tue Mar 24 01:22:45 2015
@@ -49,6 +49,7 @@ public:
     case llvm::ELF::R_X86_64_COPY:
     case llvm::ELF::R_X86_64_DTPMOD64:
     case llvm::ELF::R_X86_64_DTPOFF64:
+    case llvm::ELF::R_X86_64_TPOFF64:
       return true;
     default:
       return false;

Added: lld/trunk/test/elf/gottpoff.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/elf/gottpoff.test?rev=233051&view=auto
==============================================================================
--- lld/trunk/test/elf/gottpoff.test (added)
+++ lld/trunk/test/elf/gottpoff.test Tue Mar 24 01:22:45 2015
@@ -0,0 +1,120 @@
+# Test that GOTTPOFF reloc generates an outstanding R_X86_64_TPOFF64
+# to be processed at startup time.
+# Reference: Ulrich Drepper's "ELF Handling for Thread-Local storage"
+
+#RUN: yaml2obj -format=elf %s -o %t.o
+#RUN: lld -flavor gnu -target x86_64 %t.o -o %t -e=main --defsym=__tls_get_addr=0
+#RUN: llvm-readobj -r %t | FileCheck %s
+#
+#CHECK:   Section (5) .rela.dyn {
+#CHECK:    0x401098 R_X86_64_TPOFF64 - 0x0
+#CHECK:   }
+
+---
+FileHeader:
+  Class:           ELFCLASS64
+  Data:            ELFDATA2LSB
+  OSABI:           ELFOSABI_FREEBSD
+  Type:            ET_REL
+  Machine:         EM_X86_64
+Sections:
+  - Name:            .text
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_ALLOC, SHF_EXECINSTR ]
+    AddressAlign:    0x0000000000000010
+    Content:         E819000000640304250000000064030425000000006403042500000000C3488B0500000000648B00C3488D3D00000000E800000000488D8000000000C3
+  - Name:            .rela.text
+    Type:            SHT_RELA
+    Link:            .symtab
+    AddressAlign:    0x0000000000000008
+    Info:            .text
+    Relocations:
+      - Offset:          0x0000000000000009
+        Symbol:          tls1
+        Type:            R_X86_64_TPOFF32
+      - Offset:          0x0000000000000011
+        Symbol:          tls0
+        Type:            R_X86_64_TPOFF32
+      - Offset:          0x0000000000000019
+        Symbol:          tls2
+        Type:            R_X86_64_TPOFF32
+      - Offset:          0x0000000000000021
+        Symbol:          tls2
+        Type:            R_X86_64_GOTTPOFF
+        Addend:          -4
+      - Offset:          0x000000000000002C
+        Symbol:          tls0
+        Type:            R_X86_64_TLSLD
+        Addend:          -4
+      - Offset:          0x0000000000000031
+        Symbol:          __tls_get_addr
+        Type:            R_X86_64_PLT32
+        Addend:          -4
+      - Offset:          0x0000000000000038
+        Symbol:          tls0
+        Type:            R_X86_64_DTPOFF32
+  - Name:            .data
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         ''
+  - Name:            .bss
+    Type:            SHT_NOBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC ]
+    AddressAlign:    0x0000000000000004
+    Content:         ''
+  - Name:            .tbss
+    Type:            SHT_NOBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC, SHF_TLS ]
+    AddressAlign:    0x0000000000000004
+    Content:         '01000000002E7265'
+  - Name:            .tdata
+    Type:            SHT_PROGBITS
+    Flags:           [ SHF_WRITE, SHF_ALLOC, SHF_TLS ]
+    AddressAlign:    0x0000000000000004
+    Content:         '01000000'
+Symbols:
+  Local:
+    - Name:            .text
+      Type:            STT_SECTION
+      Section:         .text
+    - Name:            .data
+      Type:            STT_SECTION
+      Section:         .data
+    - Name:            .bss
+      Type:            STT_SECTION
+      Section:         .bss
+    - Name:            .tbss
+      Type:            STT_SECTION
+      Section:         .tbss
+    - Name:            .tdata
+      Type:            STT_SECTION
+      Section:         .tdata
+  Global:
+    - Name:            GOTTPOFF
+      Type:            STT_FUNC
+      Section:         .text
+      Value:           0x000000000000001E
+    - Name:            TLSLD
+      Type:            STT_FUNC
+      Section:         .text
+      Value:           0x0000000000000029
+    - Name:            main
+      Type:            STT_FUNC
+      Section:         .text
+    - Name:            tls0
+      Type:            STT_TLS
+      Section:         .tbss
+      Size:            0x0000000000000004
+    - Name:            tls1
+      Type:            STT_TLS
+      Section:         .tbss
+      Value:           0x0000000000000004
+      Size:            0x0000000000000004
+    - Name:            tls2
+      Type:            STT_TLS
+      Section:         .tdata
+      Size:            0x0000000000000004
+    - Name:            _GLOBAL_OFFSET_TABLE_
+    - Name:            __tls_get_addr
+...