cmd/link,cmd/internal/obj/riscv: add TLS support for linux/riscv64

Add support for Thread Local Storage (TLS) for linux/riscv64 with external
linking, using the initial-exec model.

Update #36641

Change-Id: I3106ef9a29cde73215830b00deff43dbec1c76e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/263478
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

3 files changed, 25 insertions, 8 deletions

diff --git a/src/cmd/internal/obj/riscv/obj.go b/src/cmd/internal/obj/riscv/obj.go
index 7bd3984e51..da49f67138 100644
--- a/src/cmd/internal/obj/riscv/obj.go
+++ b/src/cmd/internal/obj/riscv/obj.go
@@ -1984,6 +1984,13 @@ func assemble(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				ctxt.Diag("AUIPC needing PC-relative reloc missing symbol")
 				break
 			}
+			if addr.Sym.Type == objabi.STLSBSS {
+				if rt == objabi.R_RISCV_PCREL_ITYPE {
+					rt = objabi.R_RISCV_TLS_IE_ITYPE
+				} else if rt == objabi.R_RISCV_PCREL_STYPE {
+					rt = objabi.R_RISCV_TLS_IE_STYPE
+				}
+			}
 
 			rel := obj.Addrel(cursym)
 			rel.Off = int32(p.Pc)
diff --git a/src/cmd/internal/objabi/reloctype.go b/src/cmd/internal/objabi/reloctype.go
index 9e2e4a150a..938954e07a 100644
--- a/src/cmd/internal/objabi/reloctype.go
+++ b/src/cmd/internal/objabi/reloctype.go
@@ -223,6 +223,14 @@ const (
 	// AUIPC + S-type instruction pair.
 	R_RISCV_PCREL_STYPE
 
+	// R_RISCV_TLS_IE_ITYPE resolves a 32-bit TLS initial-exec TOC offset
+	// address using an AUIPC + I-type instruction pair.
+	R_RISCV_TLS_IE_ITYPE
+
+	// R_RISCV_TLS_IE_STYPE resolves a 32-bit TLS initial-exec TOC offset
+	// address using an AUIPC + S-type instruction pair.
+	R_RISCV_TLS_IE_STYPE
+
 	// R_PCRELDBL relocates s390x 2-byte aligned PC-relative addresses.
 	// TODO(mundaym): remove once variants can be serialized - see issue 14218.
 	R_PCRELDBL
diff --git a/src/cmd/internal/objabi/reloctype_string.go b/src/cmd/internal/objabi/reloctype_string.go
index 01df4cce62..693d9631f5 100644
--- a/src/cmd/internal/objabi/reloctype_string.go
+++ b/src/cmd/internal/objabi/reloctype_string.go
@@ -59,17 +59,19 @@ func _() {
 	_ = x[R_ADDRPOWER_TOCREL_DS-49]
 	_ = x[R_RISCV_PCREL_ITYPE-50]
 	_ = x[R_RISCV_PCREL_STYPE-51]
-	_ = x[R_PCRELDBL-52]
-	_ = x[R_ADDRMIPSU-53]
-	_ = x[R_ADDRMIPSTLS-54]
-	_ = x[R_ADDRCUOFF-55]
-	_ = x[R_WASMIMPORT-56]
-	_ = x[R_XCOFFREF-57]
+	_ = x[R_RISCV_TLS_IE_ITYPE-52]
+	_ = x[R_RISCV_TLS_IE_STYPE-53]
+	_ = x[R_PCRELDBL-54]
+	_ = x[R_ADDRMIPSU-55]
+	_ = x[R_ADDRMIPSTLS-56]
+	_ = x[R_ADDRCUOFF-57]
+	_ = x[R_WASMIMPORT-58]
+	_ = x[R_XCOFFREF-59]
 }
 
-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_USEIFACER_USEIFACEMETHODR_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"
+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_USEIFACER_USEIFACEMETHODR_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_RISCV_TLS_IE_ITYPER_RISCV_TLS_IE_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, 133, 140, 147, 155, 163, 171, 177, 183, 189, 199, 208, 218, 234, 245, 256, 266, 275, 288, 302, 316, 330, 346, 357, 370, 383, 397, 411, 426, 440, 454, 465, 479, 494, 511, 529, 550, 569, 588, 598, 609, 622, 633, 645, 655}
+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, 218, 234, 245, 256, 266, 275, 288, 302, 316, 330, 346, 357, 370, 383, 397, 411, 426, 440, 454, 465, 479, 494, 511, 529, 550, 569, 588, 608, 628, 638, 649, 662, 673, 685, 695}
 
 func (i RelocType) String() string {
 	i -= 1