debug/elf,cmd/link: add additional relocations for loong64

The Linker Relaxation feature on Loong64 is already supported in binutils 2.41.
The intermediate code generated after enabling this feature introduces three
reloc types R_LARCH_B26, R_LARCH_ADD32 and R_LARCH_SUB32.

The other relocation types are not currently used when running all.bash, but
in order to avoid the host tool chain making the decision to use it we don't
have to catch it every time.

The LoongArch ABI at here:
https://github.com/loongson/la-abi-specs/blob/release/la-abi.adoc

Corresponding binutils implementation:
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=be1ebb6710a8f707bd4b0eecbd00f4f4964050e5
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=1b6fccd28db14fffe75ff6755307047ef932c81e

Fixes #63725

Change-Id: I891115cfdbcf785ab494c881d5f9d1bf8748da8b
Reviewed-on: https://go-review.googlesource.com/c/go/+/537615
Reviewed-by: Cherry Mui <[email protected]>
Reviewed-by: David Chase <[email protected]>
Reviewed-by: Meidan Li <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: abner-chenc

api/next/63725.txt

@@ -0,0 +1,18 @@
+pkg debug/elf, const R_LARCH_64_PCREL = 109 #63725
+pkg debug/elf, const R_LARCH_64_PCREL R_LARCH #63725
+pkg debug/elf, const R_LARCH_ADD6 = 105 #63725
+pkg debug/elf, const R_LARCH_ADD6 R_LARCH #63725
+pkg debug/elf, const R_LARCH_ADD_ULEB128 = 107 #63725
+pkg debug/elf, const R_LARCH_ADD_ULEB128 R_LARCH #63725
+pkg debug/elf, const R_LARCH_ALIGN = 102 #63725
+pkg debug/elf, const R_LARCH_ALIGN R_LARCH #63725
+pkg debug/elf, const R_LARCH_CFA = 104 #63725
+pkg debug/elf, const R_LARCH_CFA R_LARCH #63725
+pkg debug/elf, const R_LARCH_DELETE = 101 #63725
+pkg debug/elf, const R_LARCH_DELETE R_LARCH #63725
+pkg debug/elf, const R_LARCH_PCREL20_S2 = 103 #63725
+pkg debug/elf, const R_LARCH_PCREL20_S2 R_LARCH #63725
+pkg debug/elf, const R_LARCH_SUB6 = 106 #63725
+pkg debug/elf, const R_LARCH_SUB6 R_LARCH #63725
+pkg debug/elf, const R_LARCH_SUB_ULEB128 = 108 #63725
+pkg debug/elf, const R_LARCH_SUB_ULEB128 R_LARCH #63725

src/cmd/link/internal/loadelf/ldelf.go

@@ -1022,16 +1022,32 @@ func relSize(arch *sys.Arch, pn string, elftype uint32) (uint8, uint8, error) {
 		MIPS64 | uint32(elf.R_MIPS_PC32)<<16:
 		return 4, 4, nil
 
+	case LOONG64 | uint32(elf.R_LARCH_ADD8)<<16,
+		LOONG64 | uint32(elf.R_LARCH_SUB8)<<16:
+		return 1, 1, nil
+
+	case LOONG64 | uint32(elf.R_LARCH_ADD16)<<16,
+		LOONG64 | uint32(elf.R_LARCH_SUB16)<<16:
+		return 2, 2, nil
+
 	case LOONG64 | uint32(elf.R_LARCH_SOP_PUSH_PCREL)<<16,
 		LOONG64 | uint32(elf.R_LARCH_SOP_PUSH_GPREL)<<16,
 		LOONG64 | uint32(elf.R_LARCH_SOP_PUSH_ABSOLUTE)<<16,
 		LOONG64 | uint32(elf.R_LARCH_MARK_LA)<<16,
 		LOONG64 | uint32(elf.R_LARCH_SOP_POP_32_S_0_10_10_16_S2)<<16,
 		LOONG64 | uint32(elf.R_LARCH_MARK_PCREL)<<16,
+		LOONG64 | uint32(elf.R_LARCH_ADD24)<<16,
+		LOONG64 | uint32(elf.R_LARCH_ADD32)<<16,
+		LOONG64 | uint32(elf.R_LARCH_SUB24)<<16,
+		LOONG64 | uint32(elf.R_LARCH_SUB32)<<16,
+		LOONG64 | uint32(elf.R_LARCH_B26)<<16,
 		LOONG64 | uint32(elf.R_LARCH_32_PCREL)<<16:
 		return 4, 4, nil
 
-	case LOONG64 | uint32(elf.R_LARCH_64)<<16:
+	case LOONG64 | uint32(elf.R_LARCH_64)<<16,
+		LOONG64 | uint32(elf.R_LARCH_ADD64)<<16,
+		LOONG64 | uint32(elf.R_LARCH_SUB64)<<16,
+		LOONG64 | uint32(elf.R_LARCH_64_PCREL)<<16:
 		return 8, 8, nil
 
 	case S390X | uint32(elf.R_390_8)<<16:

src/debug/elf/elf.go

@@ -2368,6 +2368,15 @@ const (
 	R_LARCH_TLS_GD_HI20                R_LARCH = 98
 	R_LARCH_32_PCREL                   R_LARCH = 99
 	R_LARCH_RELAX                      R_LARCH = 100
+	R_LARCH_DELETE                     R_LARCH = 101
+	R_LARCH_ALIGN                      R_LARCH = 102
+	R_LARCH_PCREL20_S2                 R_LARCH = 103
+	R_LARCH_CFA                        R_LARCH = 104
+	R_LARCH_ADD6                       R_LARCH = 105
+	R_LARCH_SUB6                       R_LARCH = 106
+	R_LARCH_ADD_ULEB128                R_LARCH = 107
+	R_LARCH_SUB_ULEB128                R_LARCH = 108
+	R_LARCH_64_PCREL                   R_LARCH = 109
 )
 
 var rlarchStrings = []intName{
@@ -2460,6 +2469,15 @@ var rlarchStrings = []intName{
 	{98, "R_LARCH_TLS_GD_HI20"},
 	{99, "R_LARCH_32_PCREL"},
 	{100, "R_LARCH_RELAX"},
+	{101, "R_LARCH_DELETE"},
+	{102, "R_LARCH_ALIGN"},
+	{103, "R_LARCH_PCREL20_S2"},
+	{104, "R_LARCH_CFA"},
+	{105, "R_LARCH_ADD6"},
+	{106, "R_LARCH_SUB6"},
+	{107, "R_LARCH_ADD_ULEB128"},
+	{108, "R_LARCH_SUB_ULEB128"},
+	{109, "R_LARCH_64_PCREL"},
 }
 
 func (i R_LARCH) String() string   { return stringName(uint32(i), rlarchStrings, false) }