Support for standard model ARM TLS
Add relocations and identification functions for the Initial Exec
and Global Dynamic TLS model defined in Addenda to, and Errata in,
the ABI for the ARM Architecture.
ARM uses variant 1 of the thread local storage data
structures as defined in ELF Handling for Thread-Local Storage.
The "experimental" descriptor based model that can be selected in
gcc, but not clang with -mtls-dialect=gnu2 is not supported.
The relocations R_ARM_TLS_LE12 and R_ARM_TLS_IE12GP are not
supported, I know of no ARM Toolchain that supports these relocations
as they limit the size of the TLS block.
No code relaxation is supported as the standard ARM TLS model puts
the relocations on literal data.
Support for the local dynamic model will come in a follow up patch.
Differential Revision: https://reviews.llvm.org/D22462
llvm-svn: 276095
diff --git a/lld/test/ELF/arm-tls-gd32.s b/lld/test/ELF/arm-tls-gd32.s
new file mode 100644
index 0000000..206b65d
--- /dev/null
+++ b/lld/test/ELF/arm-tls-gd32.s
@@ -0,0 +1,106 @@
+// RUN: llvm-mc %s -o %t.o -filetype=obj -triple=armv7a-linux-gnueabi
+// RUN: ld.lld %t.o -o %t.so -shared
+// RUN: llvm-readobj -s -dyn-relocations %t.so | FileCheck --check-prefix=SEC %s
+// RUN: llvm-objdump -d -triple=armv7a-linux-gnueabi %t.so | FileCheck %s
+// REQUIRES: arm
+
+// Test the handling of the global-dynamic TLS model. Dynamic Loader finds
+// module index R_ARM_TLS_DTPMOD32 and the offset within the module
+// R_ARM_TLS_DTPOFF32. One of the variables is hidden which permits relaxation
+// to local dynamic
+
+ .text
+ .syntax unified
+ .globl func
+ .p2align 2
+ .type func,%function
+func:
+.L0:
+ nop
+.L1:
+ nop
+.L2:
+ nop
+
+ .p2align 2
+// Generate R_ARM_TLS_GD32 relocations
+// Allocates a pair of GOT entries dynamically relocated by R_ARM_TLS_DTPMOD32
+// and R_ARM_TLS_DTPOFF32 respectively. The literal contains the offset of the
+// first GOT entry from the place
+.Lt0: .word x(TLSGD) + (. - .L0 - 8)
+.Lt1: .word y(TLSGD) + (. - .L1 - 8)
+.Lt2: .word z(TLSGD) + (. - .L2 - 8)
+
+// __thread int x = 10
+// __thread int y;
+// __thread int z __attribute((visibility("hidden")))
+
+ .hidden z
+ .globl z
+ .globl y
+ .globl x
+
+ .section .tbss,"awT",%nobits
+ .p2align 2
+.TLSSTART:
+ .type z, %object
+z:
+ .space 4
+ .type y, %object
+y:
+ .space 4
+ .section .tdata,"awT",%progbits
+ .p2align 2
+ .type x, %object
+x:
+ .word 10
+
+// SEC: Name: .tdata
+// SEC-NEXT: Type: SHT_PROGBITS
+// SEC-NEXT: Flags [
+// SEC-NEXT: SHF_ALLOC
+// SEC-NEXT: SHF_TLS
+// SEC-NEXT: SHF_WRITE
+// SEC-NEXT: ]
+// SEC-NEXT: Address: 0x2000
+// SEC: Size: 4
+// SEC: Name: .tbss
+// SEC-NEXT: Type: SHT_NOBITS
+// SEC-NEXT: Flags [
+// SEC-NEXT: SHF_ALLOC
+// SEC-NEXT: SHF_TLS
+// SEC-NEXT: SHF_WRITE
+// SEC-NEXT: ]
+// SEC-NEXT: Address: 0x2004
+// SEC: Size: 8
+
+// SEC: Name: .got
+// SEC-NEXT: Type: SHT_PROGBITS
+// SEC-NEXT: Flags [
+// SEC-NEXT: SHF_ALLOC
+// SEC-NEXT: SHF_WRITE
+// SEC-NEXT: ]
+// SEC-NEXT: Address: 0x204C
+// SEC: Size: 24
+
+// SEC: Dynamic Relocations {
+// SEC-NEXT: 0x205C R_ARM_TLS_DTPMOD32 -
+// SEC-NEXT: 0x204C R_ARM_TLS_DTPMOD32 x
+// SEC-NEXT: 0x2050 R_ARM_TLS_DTPOFF32 x
+// SEC-NEXT: 0x2054 R_ARM_TLS_DTPMOD32 y
+// SEC-NEXT: 0x2058 R_ARM_TLS_DTPOFF32 y
+
+
+// CHECK: Disassembly
+// CHECK-NEXT: func:
+// CHECK-NEXT: 1000: 00 f0 20 e3 nop
+// CHECK-NEXT: 1004: 00 f0 20 e3 nop
+// CHECK-NEXT: 1008: 00 f0 20 e3 nop
+
+// (0x204c - 0x100c) + (0x100c - 0x1000 - 8) = 0x1044
+// CHECK: 100c: 44 10 00 00
+// (0x2054 - 0x1010) + (0x1010 - 0x1004 - 8) = 0x1048
+// CHECK-NEXT: 1010: 48 10 00 00
+// (0x205c - 0x1014) + (0x1014 - 0x1008 - 8) = 0x104c
+// CHECK-NEXT: 1014: 4c 10 00 00
+
