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cmd/internal/obj/riscv,cmd/link: rework riscv64 call relocations 

The riscv64 assembler and linker generate three types of calls.
Most calls are made via a single JAL instruction, however this is
limited to +/-1MB of text. In the case where a call target is
unreachable (or unknown), the JAL targets an AUIPC+JALR trampoline.
All other cases use AUIPC+JALR pairs, including the case where a
single function exceeds 1MB in text size, potentially making it
impossible to reach trampolines.

Currently, the single instruction JAL call is marked with R_RISCV_CALL
and the two instruction AUIPC+JALR call is marked with
R_RISCV_PCREL_ITYPE, which is also used for memory load instructions.
This means that we have no way to identify that the latter is a call.

Switch to using R_RISCV_CALL to mark the AUIPC+JALR pair (aligning
somewhat with the elf.R_RISCV_CALL, which is deprecated in favour of
elf.R_RISCV_CALL_PLT). Add R_RISCV_JAL and use this to mark the single
instruction JAL direct calls. This is clearer and allows us to map
elf.R_RISCV_CALL_PLT to Go's R_RISCV_CALL.

Add all three types to IsDirectCall, so that direct calls are correctly
identified when a function exceeds 1MB of text.

Fixes #62465

Change-Id: Id3eea09688a2b7d6e481eae9ed0aa0d1f9a3a48f
Reviewed-on: https://go-review.googlesource.com/c/go/+/520095
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Joel Sing <joel@sing.id.au>
Reviewed-by: Than McIntosh <thanm@google.com>
This commit is contained in:
Joel Sing 2023-08-17 01:13:32 +10:00
parent 3c4f12a7d6
commit bda5e6c3d0
6 changed files with 90 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/cmd/asm/internal/asm/testdata/riscv64.s vendored
View File

@ -381,7 +381,7 @@ start:
JMP 4(X5) // 67804200 JMP 4(X5) // 67804200
// CALL and JMP to symbol are encoded as JAL (using LR or ZERO // CALL and JMP to symbol are encoded as JAL (using LR or ZERO
// respectively), with a R_RISCV_CALL relocation. The linker resolves // respectively), with a R_RISCV_JAL relocation. The linker resolves
// the real address and updates the immediate, using a trampoline in // the real address and updates the immediate, using a trampoline in
// the case where the address is not directly reachable. // the case where the address is not directly reachable.
CALL asmtest(SB) // ef000000 CALL asmtest(SB) // ef000000

9
src/cmd/internal/obj/riscv/cpu.go
View File

@ -260,8 +260,13 @@ const (
// corresponding *obj.Prog uses the temporary register. // corresponding *obj.Prog uses the temporary register.
USES_REG_TMP = 1 << iota USES_REG_TMP = 1 << iota
// NEED_CALL_RELOC is set on JAL instructions to indicate that a // NEED_JAL_RELOC is set on JAL instructions to indicate that a
// R_RISCV_CALL relocation is needed. // R_RISCV_JAL relocation is needed.
NEED_JAL_RELOC
// NEED_CALL_RELOC is set on an AUIPC instruction to indicate that it
// is the first instruction in an AUIPC + JAL pair that needs a
// R_RISCV_CALL relocation.
NEED_CALL_RELOC NEED_CALL_RELOC
// NEED_PCREL_ITYPE_RELOC is set on AUIPC instructions to indicate that // NEED_PCREL_ITYPE_RELOC is set on AUIPC instructions to indicate that

15
src/cmd/internal/obj/riscv/obj.go
View File

@ -41,7 +41,7 @@ func jalToSym(ctxt *obj.Link, p *obj.Prog, lr int16) {
} }
p.As = AJAL p.As = AJAL
p.Mark |= NEED_CALL_RELOC p.Mark |= NEED_JAL_RELOC
p.From.Type = obj.TYPE_REG p.From.Type = obj.TYPE_REG
p.From.Reg = lr p.From.Reg = lr
p.Reg = obj.REG_NONE p.Reg = obj.REG_NONE
@ -610,7 +610,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
var callCount int var callCount int
for p := cursym.Func().Text; p != nil; p = p.Link { for p := cursym.Func().Text; p != nil; p = p.Link {
markRelocs(p) markRelocs(p)
if p.Mark&NEED_CALL_RELOC == NEED_CALL_RELOC { if p.Mark&NEED_JAL_RELOC == NEED_JAL_RELOC {
callCount++ callCount++
} }
} }
@ -664,7 +664,7 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
jmp.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP} jmp.To = obj.Addr{Type: obj.TYPE_REG, Reg: REG_TMP}
p.As = AAUIPC p.As = AAUIPC
p.Mark = (p.Mark &^ NEED_CALL_RELOC) | NEED_PCREL_ITYPE_RELOC p.Mark = (p.Mark &^ NEED_JAL_RELOC) | NEED_CALL_RELOC
p.AddRestSource(obj.Addr{Type: obj.TYPE_CONST, Offset: p.To.Offset, Sym: p.To.Sym}) p.AddRestSource(obj.Addr{Type: obj.TYPE_CONST, Offset: p.To.Offset, Sym: p.To.Sym})
p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0} p.From = obj.Addr{Type: obj.TYPE_CONST, Offset: 0}
p.Reg = obj.REG_NONE p.Reg = obj.REG_NONE
@ -2345,13 +2345,13 @@ func assemble(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
for p := cursym.Func().Text; p != nil; p = p.Link { for p := cursym.Func().Text; p != nil; p = p.Link {
switch p.As { switch p.As {
case AJAL: case AJAL:
if p.Mark&NEED_CALL_RELOC == NEED_CALL_RELOC { if p.Mark&NEED_JAL_RELOC == NEED_JAL_RELOC {
rel := obj.Addrel(cursym) rel := obj.Addrel(cursym)
rel.Off = int32(p.Pc) rel.Off = int32(p.Pc)
rel.Siz = 4 rel.Siz = 4
rel.Sym = p.To.Sym rel.Sym = p.To.Sym
rel.Add = p.To.Offset rel.Add = p.To.Offset
rel.Type = objabi.R_RISCV_CALL rel.Type = objabi.R_RISCV_JAL
} }
case AJALR: case AJALR:
if p.To.Sym != nil { if p.To.Sym != nil {
@ -2361,7 +2361,10 @@ func assemble(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
case AAUIPC, AMOV, AMOVB, AMOVH, AMOVW, AMOVBU, AMOVHU, AMOVWU, AMOVF, AMOVD: case AAUIPC, AMOV, AMOVB, AMOVH, AMOVW, AMOVBU, AMOVHU, AMOVWU, AMOVF, AMOVD:
var addr *obj.Addr var addr *obj.Addr
var rt objabi.RelocType var rt objabi.RelocType
if p.Mark&NEED_PCREL_ITYPE_RELOC == NEED_PCREL_ITYPE_RELOC { if p.Mark&NEED_CALL_RELOC == NEED_CALL_RELOC {
rt = objabi.R_RISCV_CALL
addr = &p.From
} else if p.Mark&NEED_PCREL_ITYPE_RELOC == NEED_PCREL_ITYPE_RELOC {
rt = objabi.R_RISCV_PCREL_ITYPE rt = objabi.R_RISCV_PCREL_ITYPE
addr = &p.From addr = &p.From
} else if p.Mark&NEED_PCREL_STYPE_RELOC == NEED_PCREL_STYPE_RELOC { } else if p.Mark&NEED_PCREL_STYPE_RELOC == NEED_PCREL_STYPE_RELOC {

26
src/cmd/internal/objabi/reloctype.go
View File

@ -259,28 +259,31 @@ const (
// RISC-V. // RISC-V.
// R_RISCV_CALL relocates a J-type instruction with a 21 bit PC-relative // R_RISCV_JAL resolves a 20 bit offset for a J-type instruction.
// address. R_RISCV_JAL
R_RISCV_CALL
// R_RISCV_CALL_TRAMP is the same as R_RISCV_CALL but denotes the use of a // R_RISCV_JAL_TRAMP is the same as R_RISCV_JAL but denotes the use of a
// trampoline, which we may be able to avoid during relocation. These are // trampoline, which we may be able to avoid during relocation. These are
// only used by the linker and are not emitted by the compiler or assembler. // only used by the linker and are not emitted by the compiler or assembler.
R_RISCV_CALL_TRAMP R_RISCV_JAL_TRAMP
// R_RISCV_PCREL_ITYPE resolves a 32 bit PC-relative address using an // R_RISCV_CALL resolves a 32 bit PC-relative address for an AUIPC + JALR
// instruction pair.
R_RISCV_CALL
// R_RISCV_PCREL_ITYPE resolves a 32 bit PC-relative address for an
// AUIPC + I-type instruction pair. // AUIPC + I-type instruction pair.
R_RISCV_PCREL_ITYPE R_RISCV_PCREL_ITYPE
// R_RISCV_PCREL_STYPE resolves a 32 bit PC-relative address using an // R_RISCV_PCREL_STYPE resolves a 32 bit PC-relative address for an
// AUIPC + S-type instruction pair. // AUIPC + S-type instruction pair.
R_RISCV_PCREL_STYPE R_RISCV_PCREL_STYPE
// R_RISCV_TLS_IE resolves a 32 bit TLS initial-exec address using an // R_RISCV_TLS_IE resolves a 32 bit TLS initial-exec address for an
// AUIPC + I-type instruction pair. // AUIPC + I-type instruction pair.
R_RISCV_TLS_IE R_RISCV_TLS_IE
// R_RISCV_TLS_LE resolves a 32 bit TLS local-exec address using an // R_RISCV_TLS_LE resolves a 32 bit TLS local-exec address for a
// LUI + I-type instruction sequence. // LUI + I-type instruction sequence.
R_RISCV_TLS_LE R_RISCV_TLS_LE
@ -387,12 +390,13 @@ const (
// IsDirectCall reports whether r is a relocation for a direct call. // IsDirectCall reports whether r is a relocation for a direct call.
// A direct call is a CALL instruction that takes the target address // A direct call is a CALL instruction that takes the target address
// as an immediate. The address is embedded into the instruction, possibly // as an immediate. The address is embedded into the instruction(s), possibly
// with limited width. An indirect call is a CALL instruction that takes // with limited width. An indirect call is a CALL instruction that takes
// the target address in register or memory. // the target address in register or memory.
func (r RelocType) IsDirectCall() bool { func (r RelocType) IsDirectCall() bool {
switch r { switch r {
case R_CALL, R_CALLARM, R_CALLARM64, R_CALLLOONG64, R_CALLMIPS, R_CALLPOWER, R_RISCV_CALL, R_RISCV_CALL_TRAMP: case R_CALL, R_CALLARM, R_CALLARM64, R_CALLLOONG64, R_CALLMIPS, R_CALLPOWER,
R_RISCV_CALL, R_RISCV_JAL, R_RISCV_JAL_TRAMP:
return true return true
} }
return false return false

63
src/cmd/internal/objabi/reloctype_string.go
View File

@ -67,40 +67,41 @@ func _() {
_ = x[R_ADDRPOWER_TOCREL_DS-57] _ = x[R_ADDRPOWER_TOCREL_DS-57]
_ = x[R_ADDRPOWER_D34-58] _ = x[R_ADDRPOWER_D34-58]
_ = x[R_ADDRPOWER_PCREL34-59] _ = x[R_ADDRPOWER_PCREL34-59]
_ = x[R_RISCV_CALL-60] _ = x[R_RISCV_JAL-60]
_ = x[R_RISCV_CALL_TRAMP-61] _ = x[R_RISCV_JAL_TRAMP-61]
_ = x[R_RISCV_PCREL_ITYPE-62] _ = x[R_RISCV_CALL-62]
_ = x[R_RISCV_PCREL_STYPE-63] _ = x[R_RISCV_PCREL_ITYPE-63]
_ = x[R_RISCV_TLS_IE-64] _ = x[R_RISCV_PCREL_STYPE-64]
_ = x[R_RISCV_TLS_LE-65] _ = x[R_RISCV_TLS_IE-65]
_ = x[R_RISCV_GOT_HI20-66] _ = x[R_RISCV_TLS_LE-66]
_ = x[R_RISCV_PCREL_HI20-67] _ = x[R_RISCV_GOT_HI20-67]
_ = x[R_RISCV_PCREL_LO12_I-68] _ = x[R_RISCV_PCREL_HI20-68]
_ = x[R_RISCV_PCREL_LO12_S-69] _ = x[R_RISCV_PCREL_LO12_I-69]
_ = x[R_RISCV_BRANCH-70] _ = x[R_RISCV_PCREL_LO12_S-70]
_ = x[R_RISCV_RVC_BRANCH-71] _ = x[R_RISCV_BRANCH-71]
_ = x[R_RISCV_RVC_JUMP-72] _ = x[R_RISCV_RVC_BRANCH-72]
_ = x[R_PCRELDBL-73] _ = x[R_RISCV_RVC_JUMP-73]
_ = x[R_ADDRLOONG64-74] _ = x[R_PCRELDBL-74]
_ = x[R_ADDRLOONG64U-75] _ = x[R_ADDRLOONG64-75]
_ = x[R_ADDRLOONG64TLS-76] _ = x[R_ADDRLOONG64U-76]
_ = x[R_ADDRLOONG64TLSU-77] _ = x[R_ADDRLOONG64TLS-77]
_ = x[R_CALLLOONG64-78] _ = x[R_ADDRLOONG64TLSU-78]
_ = x[R_LOONG64_TLS_IE_PCREL_HI-79] _ = x[R_CALLLOONG64-79]
_ = x[R_LOONG64_TLS_IE_LO-80] _ = x[R_LOONG64_TLS_IE_PCREL_HI-80]
_ = x[R_JMPLOONG64-81] _ = x[R_LOONG64_TLS_IE_LO-81]
_ = x[R_ADDRMIPSU-82] _ = x[R_JMPLOONG64-82]
_ = x[R_ADDRMIPSTLS-83] _ = x[R_ADDRMIPSU-83]
_ = x[R_ADDRCUOFF-84] _ = x[R_ADDRMIPSTLS-84]
_ = x[R_WASMIMPORT-85] _ = x[R_ADDRCUOFF-85]
_ = x[R_XCOFFREF-86] _ = x[R_WASMIMPORT-86]
_ = x[R_PEIMAGEOFF-87] _ = x[R_XCOFFREF-87]
_ = x[R_INITORDER-88] _ = x[R_PEIMAGEOFF-88]
_ = x[R_INITORDER-89]
} }
const _RelocType_name = "R_ADDRR_ADDRPOWERR_ADDRARM64R_ADDRMIPSR_ADDROFFR_SIZER_CALLR_CALLARMR_CALLARM64R_CALLINDR_CALLPOWERR_CALLMIPSR_CONSTR_PCRELR_TLS_LER_TLS_IER_GOTOFFR_PLT0R_PLT1R_PLT2R_USEFIELDR_USETYPER_USEIFACER_USEIFACEMETHODR_USENAMEDMETHODR_METHODOFFR_KEEPR_POWER_TOCR_GOTPCRELR_JMPMIPSR_DWARFSECREFR_DWARFFILEREFR_ARM64_TLS_LER_ARM64_TLS_IER_ARM64_GOTPCRELR_ARM64_GOTR_ARM64_PCRELR_ARM64_PCREL_LDST8R_ARM64_PCREL_LDST16R_ARM64_PCREL_LDST32R_ARM64_PCREL_LDST64R_ARM64_LDST8R_ARM64_LDST16R_ARM64_LDST32R_ARM64_LDST64R_ARM64_LDST128R_POWER_TLS_LER_POWER_TLS_IER_POWER_TLSR_POWER_TLS_IE_PCREL34R_POWER_TLS_LE_TPREL34R_ADDRPOWER_DSR_ADDRPOWER_GOTR_ADDRPOWER_GOT_PCREL34R_ADDRPOWER_PCRELR_ADDRPOWER_TOCRELR_ADDRPOWER_TOCREL_DSR_ADDRPOWER_D34R_ADDRPOWER_PCREL34R_RISCV_CALLR_RISCV_CALL_TRAMPR_RISCV_PCREL_ITYPER_RISCV_PCREL_STYPER_RISCV_TLS_IER_RISCV_TLS_LER_RISCV_GOT_HI20R_RISCV_PCREL_HI20R_RISCV_PCREL_LO12_IR_RISCV_PCREL_LO12_SR_RISCV_BRANCHR_RISCV_RVC_BRANCHR_RISCV_RVC_JUMPR_PCRELDBLR_ADDRLOONG64R_ADDRLOONG64UR_ADDRLOONG64TLSR_ADDRLOONG64TLSUR_CALLLOONG64R_LOONG64_TLS_IE_PCREL_HIR_LOONG64_TLS_IE_LOR_JMPLOONG64R_ADDRMIPSUR_ADDRMIPSTLSR_ADDRCUOFFR_WASMIMPORTR_XCOFFREFR_PEIMAGEOFFR_INITORDER" const _RelocType_name = "R_ADDRR_ADDRPOWERR_ADDRARM64R_ADDRMIPSR_ADDROFFR_SIZER_CALLR_CALLARMR_CALLARM64R_CALLINDR_CALLPOWERR_CALLMIPSR_CONSTR_PCRELR_TLS_LER_TLS_IER_GOTOFFR_PLT0R_PLT1R_PLT2R_USEFIELDR_USETYPER_USEIFACER_USEIFACEMETHODR_USENAMEDMETHODR_METHODOFFR_KEEPR_POWER_TOCR_GOTPCRELR_JMPMIPSR_DWARFSECREFR_DWARFFILEREFR_ARM64_TLS_LER_ARM64_TLS_IER_ARM64_GOTPCRELR_ARM64_GOTR_ARM64_PCRELR_ARM64_PCREL_LDST8R_ARM64_PCREL_LDST16R_ARM64_PCREL_LDST32R_ARM64_PCREL_LDST64R_ARM64_LDST8R_ARM64_LDST16R_ARM64_LDST32R_ARM64_LDST64R_ARM64_LDST128R_POWER_TLS_LER_POWER_TLS_IER_POWER_TLSR_POWER_TLS_IE_PCREL34R_POWER_TLS_LE_TPREL34R_ADDRPOWER_DSR_ADDRPOWER_GOTR_ADDRPOWER_GOT_PCREL34R_ADDRPOWER_PCRELR_ADDRPOWER_TOCRELR_ADDRPOWER_TOCREL_DSR_ADDRPOWER_D34R_ADDRPOWER_PCREL34R_RISCV_JALR_RISCV_JAL_TRAMPR_RISCV_CALLR_RISCV_PCREL_ITYPER_RISCV_PCREL_STYPER_RISCV_TLS_IER_RISCV_TLS_LER_RISCV_GOT_HI20R_RISCV_PCREL_HI20R_RISCV_PCREL_LO12_IR_RISCV_PCREL_LO12_SR_RISCV_BRANCHR_RISCV_RVC_BRANCHR_RISCV_RVC_JUMPR_PCRELDBLR_ADDRLOONG64R_ADDRLOONG64UR_ADDRLOONG64TLSR_ADDRLOONG64TLSUR_CALLLOONG64R_LOONG64_TLS_IE_PCREL_HIR_LOONG64_TLS_IE_LOR_JMPLOONG64R_ADDRMIPSUR_ADDRMIPSTLSR_ADDRCUOFFR_WASMIMPORTR_XCOFFREFR_PEIMAGEOFFR_INITORDER"
var _RelocType_index = [...]uint16{0, 6, 17, 28, 38, 47, 53, 59, 68, 79, 88, 99, 109, 116, 123, 131, 139, 147, 153, 159, 165, 175, 184, 194, 210, 226, 237, 243, 254, 264, 273, 286, 300, 314, 328, 344, 355, 368, 387, 407, 427, 447, 460, 474, 488, 502, 517, 531, 545, 556, 578, 600, 614, 629, 652, 669, 687, 708, 723, 742, 754, 772, 791, 810, 824, 838, 854, 872, 892, 912, 926, 944, 960, 970, 983, 997, 1013, 1030, 1043, 1068, 1087, 1099, 1110, 1123, 1134, 1146, 1156, 1168, 1179} var _RelocType_index = [...]uint16{0, 6, 17, 28, 38, 47, 53, 59, 68, 79, 88, 99, 109, 116, 123, 131, 139, 147, 153, 159, 165, 175, 184, 194, 210, 226, 237, 243, 254, 264, 273, 286, 300, 314, 328, 344, 355, 368, 387, 407, 427, 447, 460, 474, 488, 502, 517, 531, 545, 556, 578, 600, 614, 629, 652, 669, 687, 708, 723, 742, 753, 770, 782, 801, 820, 834, 848, 864, 882, 902, 922, 936, 954, 970, 980, 993, 1007, 1023, 1040, 1053, 1078, 1097, 1109, 1120, 1133, 1144, 1156, 1166, 1178, 1189}
func (i RelocType) String() string { func (i RelocType) String() string {
i -= 1 i -= 1

49
src/cmd/link/internal/riscv64/asm.go
View File

@ -63,7 +63,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
ldr.Errorf(s, "unknown symbol %s in RISCV call", ldr.SymName(targ)) ldr.Errorf(s, "unknown symbol %s in RISCV call", ldr.SymName(targ))
} }
su := ldr.MakeSymbolUpdater(s) su := ldr.MakeSymbolUpdater(s)
su.SetRelocType(rIdx, objabi.R_RISCV_PCREL_ITYPE) su.SetRelocType(rIdx, objabi.R_RISCV_CALL)
return true return true
case objabi.ElfRelocOffset + objabi.RelocType(elf.R_RISCV_GOT_HI20): case objabi.ElfRelocOffset + objabi.RelocType(elf.R_RISCV_GOT_HI20):
@ -130,7 +130,7 @@ func adddynrel(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, s loade
r = relocs.At(rIdx) r = relocs.At(rIdx)
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_PCREL_ITYPE: case objabi.R_RISCV_CALL:
if targType != sym.SDYNIMPORT { if targType != sym.SDYNIMPORT {
// nothing to do, the relocation will be laid out in reloc // nothing to do, the relocation will be laid out in reloc
return true return true
@ -228,12 +228,12 @@ func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym,
} }
out.Write64(uint64(r.Xadd)) out.Write64(uint64(r.Xadd))
case objabi.R_RISCV_CALL, objabi.R_RISCV_CALL_TRAMP: case objabi.R_RISCV_JAL, objabi.R_RISCV_JAL_TRAMP:
out.Write64(uint64(sectoff)) out.Write64(uint64(sectoff))
out.Write64(uint64(elf.R_RISCV_JAL) | uint64(elfsym)<<32) out.Write64(uint64(elf.R_RISCV_JAL) | uint64(elfsym)<<32)
out.Write64(uint64(r.Xadd)) out.Write64(uint64(r.Xadd))
case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE:
// Find the text symbol for the AUIPC instruction targeted // Find the text symbol for the AUIPC instruction targeted
// by this relocation. // by this relocation.
relocs := ldr.Relocs(s) relocs := ldr.Relocs(s)
@ -256,7 +256,7 @@ func elfreloc1(ctxt *ld.Link, out *ld.OutBuf, ldr *loader.Loader, s loader.Sym,
// //
var hiRel, loRel elf.R_RISCV var hiRel, loRel elf.R_RISCV
switch r.Type { switch r.Type {
case objabi.R_RISCV_PCREL_ITYPE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE:
hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_I hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_I
case objabi.R_RISCV_PCREL_STYPE: case objabi.R_RISCV_PCREL_STYPE:
hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_S hiRel, loRel = elf.R_RISCV_PCREL_HI20, elf.R_RISCV_PCREL_LO12_S
@ -399,20 +399,20 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
// If the call points to a trampoline, see if we can reach the symbol // If the call points to a trampoline, see if we can reach the symbol
// directly. This situation can occur when the relocation symbol is // directly. This situation can occur when the relocation symbol is
// not assigned an address until after the trampolines are generated. // not assigned an address until after the trampolines are generated.
if r.Type() == objabi.R_RISCV_CALL_TRAMP { if r.Type() == objabi.R_RISCV_JAL_TRAMP {
relocs := ldr.Relocs(rs) relocs := ldr.Relocs(rs)
if relocs.Count() != 1 { if relocs.Count() != 1 {
ldr.Errorf(s, "trampoline %v has %d relocations", ldr.SymName(rs), relocs.Count()) ldr.Errorf(s, "trampoline %v has %d relocations", ldr.SymName(rs), relocs.Count())
} }
tr := relocs.At(0) tr := relocs.At(0)
if tr.Type() != objabi.R_RISCV_PCREL_ITYPE { if tr.Type() != objabi.R_RISCV_CALL {
ldr.Errorf(s, "trampoline %v has unexpected relocation %v", ldr.SymName(rs), tr.Type()) ldr.Errorf(s, "trampoline %v has unexpected relocation %v", ldr.SymName(rs), tr.Type())
} }
trs := tr.Sym() trs := tr.Sym()
if ldr.SymValue(trs) != 0 && ldr.SymType(trs) != sym.SDYNIMPORT && ldr.SymType(trs) != sym.SUNDEFEXT { if ldr.SymValue(trs) != 0 && ldr.SymType(trs) != sym.SDYNIMPORT && ldr.SymType(trs) != sym.SUNDEFEXT {
trsOff := ldr.SymValue(trs) + tr.Add() - pc trsOff := ldr.SymValue(trs) + tr.Add() - pc
if trsOff >= -(1<<20) && trsOff < (1<<20) { if trsOff >= -(1<<20) && trsOff < (1<<20) {
r.SetType(objabi.R_RISCV_CALL) r.SetType(objabi.R_RISCV_JAL)
r.SetSym(trs) r.SetSym(trs)
r.SetAdd(tr.Add()) r.SetAdd(tr.Add())
rs = trs rs = trs
@ -423,10 +423,10 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
if target.IsExternal() { if target.IsExternal() {
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_CALL, objabi.R_RISCV_CALL_TRAMP: case objabi.R_RISCV_JAL, objabi.R_RISCV_JAL_TRAMP:
return val, 1, true return val, 1, true
case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE, objabi.R_RISCV_TLS_LE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE, objabi.R_RISCV_TLS_LE:
return val, 2, true return val, 2, true
} }
@ -436,11 +436,11 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
off := ldr.SymValue(rs) + r.Add() - pc off := ldr.SymValue(rs) + r.Add() - pc
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_CALL, objabi.R_RISCV_CALL_TRAMP: case objabi.R_RISCV_JAL, objabi.R_RISCV_JAL_TRAMP:
// Generate instruction immediates. // Generate instruction immediates.
imm, err := riscv.EncodeJImmediate(off) imm, err := riscv.EncodeJImmediate(off)
if err != nil { if err != nil {
ldr.Errorf(s, "cannot encode R_RISCV_CALL relocation offset for %s: %v", ldr.SymName(rs), err) ldr.Errorf(s, "cannot encode J-type instruction relocation offset for %s: %v", ldr.SymName(rs), err)
} }
immMask := int64(riscv.JTypeImmMask) immMask := int64(riscv.JTypeImmMask)
@ -574,31 +574,31 @@ func archreloc(target *ld.Target, ldr *loader.Loader, syms *ld.ArchSyms, r loade
ins = (ins &^ immMask) | int64(uint32(imm)) ins = (ins &^ immMask) | int64(uint32(imm))
return ins, 0, true return ins, 0, true
case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE:
// Generate AUIPC and second instruction immediates. // Generate AUIPC and second instruction immediates.
low, high, err := riscv.Split32BitImmediate(off) low, high, err := riscv.Split32BitImmediate(off)
if err != nil { if err != nil {
ldr.Errorf(s, "R_RISCV_PCREL_ relocation does not fit in 32 bits: %d", off) ldr.Errorf(s, "pc-relative relocation does not fit in 32 bits: %d", off)
} }
auipcImm, err := riscv.EncodeUImmediate(high) auipcImm, err := riscv.EncodeUImmediate(high)
if err != nil { if err != nil {
ldr.Errorf(s, "cannot encode R_RISCV_PCREL_ AUIPC relocation offset for %s: %v", ldr.SymName(rs), err) ldr.Errorf(s, "cannot encode AUIPC relocation offset for %s: %v", ldr.SymName(rs), err)
} }
var secondImm, secondImmMask int64 var secondImm, secondImmMask int64
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_PCREL_ITYPE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE:
secondImmMask = riscv.ITypeImmMask secondImmMask = riscv.ITypeImmMask
secondImm, err = riscv.EncodeIImmediate(low) secondImm, err = riscv.EncodeIImmediate(low)
if err != nil { if err != nil {
ldr.Errorf(s, "cannot encode R_RISCV_PCREL_ITYPE I-type instruction relocation offset for %s: %v", ldr.SymName(rs), err) ldr.Errorf(s, "cannot encode I-type instruction relocation offset for %s: %v", ldr.SymName(rs), err)
} }
case objabi.R_RISCV_PCREL_STYPE: case objabi.R_RISCV_PCREL_STYPE:
secondImmMask = riscv.STypeImmMask secondImmMask = riscv.STypeImmMask
secondImm, err = riscv.EncodeSImmediate(low) secondImm, err = riscv.EncodeSImmediate(low)
if err != nil { if err != nil {
ldr.Errorf(s, "cannot encode R_RISCV_PCREL_STYPE S-type instruction relocation offset for %s: %v", ldr.SymName(rs), err) ldr.Errorf(s, "cannot encode S-type instruction relocation offset for %s: %v", ldr.SymName(rs), err)
} }
default: default:
panic(fmt.Sprintf("unknown relocation type: %v", r.Type())) panic(fmt.Sprintf("unknown relocation type: %v", r.Type()))
@ -623,10 +623,10 @@ func archrelocvariant(*ld.Target, *loader.Loader, loader.Reloc, sym.RelocVariant
func extreloc(target *ld.Target, ldr *loader.Loader, r loader.Reloc, s loader.Sym) (loader.ExtReloc, bool) { func extreloc(target *ld.Target, ldr *loader.Loader, r loader.Reloc, s loader.Sym) (loader.ExtReloc, bool) {
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_CALL, objabi.R_RISCV_CALL_TRAMP: case objabi.R_RISCV_JAL, objabi.R_RISCV_JAL_TRAMP:
return ld.ExtrelocSimple(ldr, r), true return ld.ExtrelocSimple(ldr, r), true
case objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE, objabi.R_RISCV_TLS_LE: case objabi.R_RISCV_CALL, objabi.R_RISCV_PCREL_ITYPE, objabi.R_RISCV_PCREL_STYPE, objabi.R_RISCV_TLS_IE, objabi.R_RISCV_TLS_LE:
return ld.ExtrelocViaOuterSym(ldr, r, s), true return ld.ExtrelocViaOuterSym(ldr, r, s), true
} }
return loader.ExtReloc{}, false return loader.ExtReloc{}, false
@ -637,7 +637,7 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
r := relocs.At(ri) r := relocs.At(ri)
switch r.Type() { switch r.Type() {
case objabi.R_RISCV_CALL: case objabi.R_RISCV_JAL:
pc := ldr.SymValue(s) + int64(r.Off()) pc := ldr.SymValue(s) + int64(r.Off())
off := ldr.SymValue(rs) + r.Add() - pc off := ldr.SymValue(rs) + r.Add() - pc
@ -691,13 +691,16 @@ func trampoline(ctxt *ld.Link, ldr *loader.Loader, ri int, rs, s loader.Sym) {
// address, so we have to assume a trampoline is required. Mark // address, so we have to assume a trampoline is required. Mark
// this as a call via a trampoline so that we can potentially // this as a call via a trampoline so that we can potentially
// switch to a direct call during relocation. // switch to a direct call during relocation.
sb.SetRelocType(ri, objabi.R_RISCV_CALL_TRAMP) sb.SetRelocType(ri, objabi.R_RISCV_JAL_TRAMP)
} }
relocs := sb.Relocs() relocs := sb.Relocs()
r := relocs.At(ri) r := relocs.At(ri)
r.SetSym(tramp) r.SetSym(tramp)
r.SetAdd(0) r.SetAdd(0)
case objabi.R_RISCV_CALL:
// Nothing to do, already using AUIPC+JALR.
default: default:
ctxt.Errorf(s, "trampoline called with non-jump reloc: %d (%s)", r.Type(), sym.RelocName(ctxt.Arch, r.Type())) ctxt.Errorf(s, "trampoline called with non-jump reloc: %d (%s)", r.Type(), sym.RelocName(ctxt.Arch, r.Type()))
} }
@ -707,7 +710,7 @@ func genCallTramp(arch *sys.Arch, linkmode ld.LinkMode, ldr *loader.Loader, tram
tramp.AddUint32(arch, 0x00000f97) // AUIPC $0, X31 tramp.AddUint32(arch, 0x00000f97) // AUIPC $0, X31
tramp.AddUint32(arch, 0x000f8067) // JALR X0, (X31) tramp.AddUint32(arch, 0x000f8067) // JALR X0, (X31)
r, _ := tramp.AddRel(objabi.R_RISCV_PCREL_ITYPE) r, _ := tramp.AddRel(objabi.R_RISCV_CALL)
r.SetSiz(8) r.SetSiz(8)
r.SetSym(target) r.SetSym(target)
r.SetAdd(offset) r.SetAdd(offset)