cmd/internal/objabi,cmd/link: initial linker support for riscv64

Provide initial linker support for riscv64.

Based on riscv-go port.

Updates #27532

Change-Id: I8a881ce41cd49efef0358bad9171d4d18aaf7ab2
Reviewed-on: https://go-review.googlesource.com/c/go/+/204624
Run-TryBot: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

2 files changed, 16 insertions, 3 deletions

diff --git a/src/cmd/internal/objabi/reloctype.go b/src/cmd/internal/objabi/reloctype.go
index aed7e2a74d..dc6482802a 100644
--- a/src/cmd/internal/objabi/reloctype.go
+++ b/src/cmd/internal/objabi/reloctype.go
@@ -64,6 +64,8 @@ const (
 	// R_CALLMIPS (only used on mips64) resolves to non-PC-relative target address
 	// of a CALL (JAL) instruction, by encoding the address into the instruction.
 	R_CALLMIPS
+	// R_CALLRISCV marks RISC-V CALLs for stack checking.
+	R_CALLRISCV
 	R_CONST
 	R_PCREL
 	// R_TLS_LE, used on 386, amd64, and ARM, resolves to the offset of the
@@ -200,6 +202,16 @@ const (
 	// relocated symbol rather than the symbol's address.
 	R_ADDRPOWER_TOCREL_DS
 
+	// RISC-V.
+
+	// R_RISCV_PCREL_ITYPE resolves a 32-bit PC-relative address using an
+	// AUIPC + I-type instruction pair.
+	R_RISCV_PCREL_ITYPE
+
+	// R_RISCV_PCREL_STYPE resolves a 32-bit PC-relative address using an
+	// AUIPC + S-type instruction pair.
+	R_RISCV_PCREL_STYPE
+
 	// R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses.
 	// TODO(mundaym): remove once variants can be serialized - see issue 14218.
 	R_PCRELDBL
@@ -210,6 +222,7 @@ const (
 	// R_ADDRMIPSTLS (only used on mips64) resolves to the low 16 bits of a TLS
 	// address (offset from thread pointer), by encoding it into the instruction.
 	R_ADDRMIPSTLS
+
 	// R_ADDRCUOFF resolves to a pointer-sized offset from the start of the
 	// symbol's DWARF compile unit.
 	R_ADDRCUOFF
@@ -230,7 +243,7 @@ const (
 // the target address in register or memory.
 func (r RelocType) IsDirectCall() bool {
 	switch r {
-	case R_CALL, R_CALLARM, R_CALLARM64, R_CALLMIPS, R_CALLPOWER:
+	case R_CALL, R_CALLARM, R_CALLARM64, R_CALLMIPS, R_CALLPOWER, R_CALLRISCV:
 		return true
 	}
 	return false
diff --git a/src/cmd/internal/objabi/reloctype_string.go b/src/cmd/internal/objabi/reloctype_string.go
index a1c4c1aa51..83dfe71e07 100644
--- a/src/cmd/internal/objabi/reloctype_string.go
+++ b/src/cmd/internal/objabi/reloctype_string.go
@@ -4,9 +4,9 @@ package objabi
 
 import "strconv"
 
-const _RelocType_name = "R_ADDRR_ADDRPOWERR_ADDRARM64R_ADDRMIPSR_ADDROFFR_WEAKADDROFFR_SIZER_CALLR_CALLARMR_CALLARM64R_CALLINDR_CALLPOWERR_CALLMIPSR_CONSTR_PCRELR_TLS_LER_TLS_IER_GOTOFFR_PLT0R_PLT1R_PLT2R_USEFIELDR_USETYPER_METHODOFFR_POWER_TOCR_GOTPCRELR_JMPMIPSR_DWARFSECREFR_DWARFFILEREFR_ARM64_TLS_LER_ARM64_TLS_IER_ARM64_GOTPCRELR_ARM64_GOTR_ARM64_PCRELR_ARM64_LDST8R_ARM64_LDST32R_ARM64_LDST64R_ARM64_LDST128R_POWER_TLS_LER_POWER_TLS_IER_POWER_TLSR_ADDRPOWER_DSR_ADDRPOWER_GOTR_ADDRPOWER_PCRELR_ADDRPOWER_TOCRELR_ADDRPOWER_TOCREL_DSR_PCRELDBLR_ADDRMIPSUR_ADDRMIPSTLSR_ADDRCUOFFR_WASMIMPORTR_XCOFFREF"
+const _RelocType_name = "R_ADDRR_ADDRPOWERR_ADDRARM64R_ADDRMIPSR_ADDROFFR_WEAKADDROFFR_SIZER_CALLR_CALLARMR_CALLARM64R_CALLINDR_CALLPOWERR_CALLMIPSR_CALLRISCVR_CONSTR_PCRELR_TLS_LER_TLS_IER_GOTOFFR_PLT0R_PLT1R_PLT2R_USEFIELDR_USETYPER_METHODOFFR_POWER_TOCR_GOTPCRELR_JMPMIPSR_DWARFSECREFR_DWARFFILEREFR_ARM64_TLS_LER_ARM64_TLS_IER_ARM64_GOTPCRELR_ARM64_GOTR_ARM64_PCRELR_ARM64_LDST8R_ARM64_LDST32R_ARM64_LDST64R_ARM64_LDST128R_POWER_TLS_LER_POWER_TLS_IER_POWER_TLSR_ADDRPOWER_DSR_ADDRPOWER_GOTR_ADDRPOWER_PCRELR_ADDRPOWER_TOCRELR_ADDRPOWER_TOCREL_DSR_RISCV_PCREL_ITYPER_RISCV_PCREL_STYPER_PCRELDBLR_ADDRMIPSUR_ADDRMIPSTLSR_ADDRCUOFFR_WASMIMPORTR_XCOFFREF"
 
-var _RelocType_index = [...]uint16{0, 6, 17, 28, 38, 47, 60, 66, 72, 81, 92, 101, 112, 122, 129, 136, 144, 152, 160, 166, 172, 178, 188, 197, 208, 219, 229, 238, 251, 265, 279, 293, 309, 320, 333, 346, 360, 374, 389, 403, 417, 428, 442, 457, 474, 492, 513, 523, 534, 547, 558, 570, 580}
+var _RelocType_index = [...]uint16{0, 6, 17, 28, 38, 47, 60, 66, 72, 81, 92, 101, 112, 122, 133, 140, 147, 155, 163, 171, 177, 183, 189, 199, 208, 219, 230, 240, 249, 262, 276, 290, 304, 320, 331, 344, 357, 371, 385, 400, 414, 428, 439, 453, 468, 485, 503, 524, 543, 562, 572, 583, 596, 607, 619, 629}
 
 func (i RelocType) String() string {
 	i -= 1