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cmd/link: support new 386/amd64 relocations
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The GNU binutils recently picked up support for new 386/amd64
relocations.  Add support for them in the Go linker when doing an
internal link.

The 386 relocation R_386_GOT32X was proposed in
https://groups.google.com/forum/#!topic/ia32-abi/GbJJskkid4I .  It can
be treated as identical to the R_386_GOT32 relocation.

The amd64 relocations R_X86_64_GOTPCRELX and R_X86_64_REX_GOTPCRELX were
proposed in
https://groups.google.com/forum/#!topic/x86-64-abi/n9AWHogmVY0 .  They
can both be treated as identical to the R_X86_64_GOTPCREL relocation.

The purpose of the new relocations is to permit additional linker
relaxations in some cases.  We do not attempt to support those cases.

While we're at it, remove the unused and in some cases out of date
_COUNT names from ld/elf.go.

Fixes #13114.

Change-Id: I34ef07f6fcd00cdd2996038ecf46bb77a49e968b
Reviewed-on: https://go-review.googlesource.com/16529
Reviewed-by: Minux Ma <minux@golang.org>
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@ianlancetaylor
ianlancetaylor committed Oct 31, 2015
1 parent ce30458 commit 914db9f
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Showing 4 changed files with 83 additions and 64 deletions.
2 changes: 1 addition & 1 deletion src/cmd/link/internal/amd64/asm.go
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Original file line number Diff line number Diff line change
Expand Up @@ -139,7 +139,7 @@ func adddynrel(s *ld.LSym, r *ld.Reloc) {

return

case 256 + ld.R_X86_64_GOTPCREL:
case 256 + ld.R_X86_64_GOTPCREL, 256 + ld.R_X86_64_GOTPCRELX, 256 + ld.R_X86_64_REX_GOTPCRELX:
if targ.Type != obj.SDYNIMPORT {
// have symbol
if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
Expand Down
140 changes: 78 additions & 62 deletions src/cmd/link/internal/ld/elf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -325,31 +325,47 @@ const (
* Relocation types.
*/
const (
R_X86_64_NONE = 0
R_X86_64_64 = 1
R_X86_64_PC32 = 2
R_X86_64_GOT32 = 3
R_X86_64_PLT32 = 4
R_X86_64_COPY = 5
R_X86_64_GLOB_DAT = 6
R_X86_64_JMP_SLOT = 7
R_X86_64_RELATIVE = 8
R_X86_64_GOTPCREL = 9
R_X86_64_32 = 10
R_X86_64_32S = 11
R_X86_64_16 = 12
R_X86_64_PC16 = 13
R_X86_64_8 = 14
R_X86_64_PC8 = 15
R_X86_64_DTPMOD64 = 16
R_X86_64_DTPOFF64 = 17
R_X86_64_TPOFF64 = 18
R_X86_64_TLSGD = 19
R_X86_64_TLSLD = 20
R_X86_64_DTPOFF32 = 21
R_X86_64_GOTTPOFF = 22
R_X86_64_TPOFF32 = 23
R_X86_64_COUNT = 24
R_X86_64_NONE = 0
R_X86_64_64 = 1
R_X86_64_PC32 = 2
R_X86_64_GOT32 = 3
R_X86_64_PLT32 = 4
R_X86_64_COPY = 5
R_X86_64_GLOB_DAT = 6
R_X86_64_JMP_SLOT = 7
R_X86_64_RELATIVE = 8
R_X86_64_GOTPCREL = 9
R_X86_64_32 = 10
R_X86_64_32S = 11
R_X86_64_16 = 12
R_X86_64_PC16 = 13
R_X86_64_8 = 14
R_X86_64_PC8 = 15
R_X86_64_DTPMOD64 = 16
R_X86_64_DTPOFF64 = 17
R_X86_64_TPOFF64 = 18
R_X86_64_TLSGD = 19
R_X86_64_TLSLD = 20
R_X86_64_DTPOFF32 = 21
R_X86_64_GOTTPOFF = 22
R_X86_64_TPOFF32 = 23
R_X86_64_PC64 = 24
R_X86_64_GOTOFF64 = 25
R_X86_64_GOTPC32 = 26
R_X86_64_GOT64 = 27
R_X86_64_GOTPCREL64 = 28
R_X86_64_GOTPC64 = 29
R_X86_64_GOTPLT64 = 30
R_X86_64_PLTOFF64 = 31
R_X86_64_SIZE32 = 32
R_X86_64_SIZE64 = 33
R_X86_64_GOTPC32_TLSDEC = 34
R_X86_64_TLSDESC_CALL = 35
R_X86_64_TLSDESC = 36
R_X86_64_IRELATIVE = 37
R_X86_64_PC32_BND = 40
R_X86_64_GOTPCRELX = 41
R_X86_64_REX_GOTPCRELX = 42

R_AARCH64_ABS64 = 257
R_AARCH64_ABS32 = 258
Expand Down Expand Up @@ -388,7 +404,6 @@ const (
R_ALPHA_GLOB_DAT = 25
R_ALPHA_JMP_SLOT = 26
R_ALPHA_RELATIVE = 27
R_ALPHA_COUNT = 28

R_ARM_NONE = 0
R_ARM_PC24 = 1
Expand Down Expand Up @@ -429,40 +444,43 @@ const (
R_ARM_RABS32 = 253
R_ARM_RPC24 = 254
R_ARM_RBASE = 255
R_ARM_COUNT = 38

R_386_NONE = 0
R_386_32 = 1
R_386_PC32 = 2
R_386_GOT32 = 3
R_386_PLT32 = 4
R_386_COPY = 5
R_386_GLOB_DAT = 6
R_386_JMP_SLOT = 7
R_386_RELATIVE = 8
R_386_GOTOFF = 9
R_386_GOTPC = 10
R_386_TLS_TPOFF = 14
R_386_TLS_IE = 15
R_386_TLS_GOTIE = 16
R_386_TLS_LE = 17
R_386_TLS_GD = 18
R_386_TLS_LDM = 19
R_386_TLS_GD_32 = 24
R_386_TLS_GD_PUSH = 25
R_386_TLS_GD_CALL = 26
R_386_TLS_GD_POP = 27
R_386_TLS_LDM_32 = 28
R_386_TLS_LDM_PUSH = 29
R_386_TLS_LDM_CALL = 30
R_386_TLS_LDM_POP = 31
R_386_TLS_LDO_32 = 32
R_386_TLS_IE_32 = 33
R_386_TLS_LE_32 = 34
R_386_TLS_DTPMOD32 = 35
R_386_TLS_DTPOFF32 = 36
R_386_TLS_TPOFF32 = 37
R_386_COUNT = 38

R_386_NONE = 0
R_386_32 = 1
R_386_PC32 = 2
R_386_GOT32 = 3
R_386_PLT32 = 4
R_386_COPY = 5
R_386_GLOB_DAT = 6
R_386_JMP_SLOT = 7
R_386_RELATIVE = 8
R_386_GOTOFF = 9
R_386_GOTPC = 10
R_386_TLS_TPOFF = 14
R_386_TLS_IE = 15
R_386_TLS_GOTIE = 16
R_386_TLS_LE = 17
R_386_TLS_GD = 18
R_386_TLS_LDM = 19
R_386_TLS_GD_32 = 24
R_386_TLS_GD_PUSH = 25
R_386_TLS_GD_CALL = 26
R_386_TLS_GD_POP = 27
R_386_TLS_LDM_32 = 28
R_386_TLS_LDM_PUSH = 29
R_386_TLS_LDM_CALL = 30
R_386_TLS_LDM_POP = 31
R_386_TLS_LDO_32 = 32
R_386_TLS_IE_32 = 33
R_386_TLS_LE_32 = 34
R_386_TLS_DTPMOD32 = 35
R_386_TLS_DTPOFF32 = 36
R_386_TLS_TPOFF32 = 37
R_386_TLS_GOTDESC = 39
R_386_TLS_DESC_CALL = 40
R_386_TLS_DESC = 41
R_386_IRELATIVE = 42
R_386_GOT32X = 43

R_PPC_NONE = 0
R_PPC_ADDR32 = 1
Expand Down Expand Up @@ -501,7 +519,6 @@ const (
R_PPC_SECTOFF_LO = 34
R_PPC_SECTOFF_HI = 35
R_PPC_SECTOFF_HA = 36
R_PPC_COUNT = 37
R_PPC_TLS = 67
R_PPC_DTPMOD32 = 68
R_PPC_TPREL16 = 69
Expand Down Expand Up @@ -542,7 +559,6 @@ const (
R_PPC_EMB_RELST_HA = 114
R_PPC_EMB_BIT_FLD = 115
R_PPC_EMB_RELSDA = 116
R_PPC_EMB_COUNT = R_PPC_EMB_RELSDA - R_PPC_EMB_NADDR32 + 1

R_PPC64_REL24 = R_PPC_REL24
R_PPC64_JMP_SLOT = R_PPC_JMP_SLOT
Expand Down
3 changes: 3 additions & 0 deletions src/cmd/link/internal/ld/ldelf.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1137,12 +1137,15 @@ func reltype(pn string, elftype int, siz *uint8) int {
'6' | R_X86_64_PC32<<24,
'6' | R_X86_64_PLT32<<24,
'6' | R_X86_64_GOTPCREL<<24,
'6' | R_X86_64_GOTPCRELX<<24,
'6' | R_X86_64_REX_GOTPCRELX<<24,
'8' | R_386_32<<24,
'8' | R_386_PC32<<24,
'8' | R_386_GOT32<<24,
'8' | R_386_PLT32<<24,
'8' | R_386_GOTOFF<<24,
'8' | R_386_GOTPC<<24,
'8' | R_386_GOT32X<<24,
'9' | R_PPC64_REL24<<24:
*siz = 4

Expand Down
2 changes: 1 addition & 1 deletion src/cmd/link/internal/x86/asm.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,7 @@ func adddynrel(s *ld.LSym, r *ld.Reloc) {

return

case 256 + ld.R_386_GOT32:
case 256 + ld.R_386_GOT32, 256 + ld.R_386_GOT32X:
if targ.Type != obj.SDYNIMPORT {
// have symbol
if r.Off >= 2 && s.P[r.Off-2] == 0x8b {
Expand Down

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