commit 656afe370df3ac374db7624e0b450f15a2212ab2
author Fangrui Song <maskray@google.com> Wed May 29 02:02:59 2019 +0000
committer Fangrui Song <maskray@google.com> Wed May 29 02:02:59 2019 +0000
tree 207ecb0fceff3bdbf3220c9b3210f8ee86ba699e
parent 529118fc87c0ca274a4355c3f90ddd7b07215b2d

[X86] Fix x86-64 call *foo@tlsdesc(%rax) and support R_386_TLSGOTDESC R_386_TLS_DESC_CALL

D18885 emitted 5 bytes for call *foo@tlsdesc(%rax). It should use the
2-byte form instead and let R_X86_64_TLSDESC_CALL apply to the beginning
of the call instruction.

The 2-byte form was deliberately chosen to make ->LE and ->IE relaxation work:

    0:   48 8d 05 00 00 00 00    lea    0x0(%rip),%rax        # 7 <.text+0x7>
                         3: R_X86_64_GOTPC32_TLSDESC     a-0x4
    7:   ff 10                   callq  *(%rax)
                         7: R_X86_64_TLSDESC_CALL        a

=>

    0:   48 c7 c0 fc ff ff ff    mov    $0xfffffffffffffffc,%rax
    7:   66 90                   xchg   %ax,%ax

Also change the symbol type to STT_TLS when VK_TLSCALL or VK_TLSDESC is
seen.

Reviewed By: compnerd

Differential Revision: https://reviews.llvm.org/D62512

llvm-svn: 361910

llvm/lib/MC/MCELFStreamer.cpp

diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 6fe16abd..245dd06 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -400,6 +400,8 @@
     case MCSymbolRefExpr::VK_INDNTPOFF:
     case MCSymbolRefExpr::VK_NTPOFF:
     case MCSymbolRefExpr::VK_GOTNTPOFF:
+    case MCSymbolRefExpr::VK_TLSCALL:
+    case MCSymbolRefExpr::VK_TLSDESC:
     case MCSymbolRefExpr::VK_TLSGD:
     case MCSymbolRefExpr::VK_TLSLD:
     case MCSymbolRefExpr::VK_TLSLDM: