cmd/internal/obj/arm64, cmd/link: use two instructions rather than three for loads...

Reduces size of godoc .text section by about 75k (or 1.4%).

Change-Id: I65850aa569aefbddd6cb07c6ae1addcc39cab6a5
Reviewed-on: https://go-review.googlesource.com/13993
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/cmd/internal/obj/arm64/asm7.go b/src/cmd/internal/obj/arm64/asm7.go
index 1fd8982a988cef419bedc76b22ccb84928fa5841..ae596cfaa47ae73f18f7257dedfe9b5ad612688a 100644 (file)
--- a/src/cmd/internal/obj/arm64/asm7.go
+++ b/src/cmd/internal/obj/arm64/asm7.go
@@ -260,16 +260,16 @@ var optab = []Optab{
        {AMOVW, C_VCONADDR, C_NONE, C_REG, 68, 8, 0, 0, 0},
        {AMOVD, C_VCON, C_NONE, C_REG, 12, 4, 0, LFROM, 0},
        {AMOVD, C_VCONADDR, C_NONE, C_REG, 68, 8, 0, 0, 0},
-       {AMOVB, C_REG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AMOVBU, C_REG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AMOVH, C_REG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AMOVW, C_REG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AMOVD, C_REG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AMOVB, C_ADDR, C_NONE, C_REG, 65, 12, 0, 0, 0},
-       {AMOVBU, C_ADDR, C_NONE, C_REG, 65, 12, 0, 0, 0},
-       {AMOVH, C_ADDR, C_NONE, C_REG, 65, 12, 0, 0, 0},
-       {AMOVW, C_ADDR, C_NONE, C_REG, 65, 12, 0, 0, 0},
-       {AMOVD, C_ADDR, C_NONE, C_REG, 65, 12, 0, 0, 0},
+       {AMOVB, C_REG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AMOVBU, C_REG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AMOVH, C_REG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AMOVW, C_REG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AMOVD, C_REG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AMOVB, C_ADDR, C_NONE, C_REG, 65, 8, 0, 0, 0},
+       {AMOVBU, C_ADDR, C_NONE, C_REG, 65, 8, 0, 0, 0},
+       {AMOVH, C_ADDR, C_NONE, C_REG, 65, 8, 0, 0, 0},
+       {AMOVW, C_ADDR, C_NONE, C_REG, 65, 8, 0, 0, 0},
+       {AMOVD, C_ADDR, C_NONE, C_REG, 65, 8, 0, 0, 0},
        {AMOVD, C_TLS_LE, C_NONE, C_REG, 69, 4, 0, 0, 0},
        {AMOVD, C_TLS_IE, C_NONE, C_REG, 70, 8, 0, 0, 0},
        {AMUL, C_REG, C_REG, C_REG, 15, 4, 0, 0, 0},
@@ -450,10 +450,10 @@ var optab = []Optab{
        {AFMOVS, C_LOREG, C_NONE, C_FREG, 31, 8, 0, LFROM, 0},
        {AFMOVD, C_LAUTO, C_NONE, C_FREG, 31, 8, REGSP, LFROM, 0},
        {AFMOVD, C_LOREG, C_NONE, C_FREG, 31, 8, 0, LFROM, 0},
-       {AFMOVS, C_FREG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AFMOVS, C_ADDR, C_NONE, C_FREG, 65, 12, 0, 0, 0},
-       {AFMOVD, C_FREG, C_NONE, C_ADDR, 64, 12, 0, 0, 0},
-       {AFMOVD, C_ADDR, C_NONE, C_FREG, 65, 12, 0, 0, 0},
+       {AFMOVS, C_FREG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AFMOVS, C_ADDR, C_NONE, C_FREG, 65, 8, 0, 0, 0},
+       {AFMOVD, C_FREG, C_NONE, C_ADDR, 64, 8, 0, 0, 0},
+       {AFMOVD, C_ADDR, C_NONE, C_FREG, 65, 8, 0, 0, 0},
        {AFADDS, C_FREG, C_NONE, C_FREG, 54, 4, 0, 0, 0},
        {AFADDS, C_FREG, C_FREG, C_FREG, 54, 4, 0, 0, 0},
        {AFADDS, C_FCON, C_NONE, C_FREG, 54, 4, 0, 0, 0},
@@ -2701,28 +2701,26 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
 
                o1 = ADR(0, uint32(d), uint32(p.To.Reg))
 
-               /* reloc ops */
+       /* reloc ops */
        case 64: /* movT R,addr -> adrp + add + movT R, (REGTMP) */
                o1 = ADR(1, 0, REGTMP)
-               o2 = opirr(ctxt, AADD) | REGTMP&31<<5 | REGTMP&31
+               o2 = olsr12u(ctxt, int32(opstr12(ctxt, int(p.As))), 0, REGTMP, int(p.From.Reg))
                rel := obj.Addrel(ctxt.Cursym)
                rel.Off = int32(ctxt.Pc)
                rel.Siz = 8
                rel.Sym = p.To.Sym
                rel.Add = p.To.Offset
-               rel.Type = obj.R_ADDRARM64
-               o3 = olsr12u(ctxt, int32(opstr12(ctxt, int(p.As))), 0, REGTMP, int(p.From.Reg))
+               rel.Type = movereloc(p.As)
 
-       case 65: /* movT addr,R -> adrp + add + movT (REGTMP), R */
+       case 65: /* movT addr,R -> adrp REGTMP, 0; ldr R, [REGTMP, #0] + relocs */
                o1 = ADR(1, 0, REGTMP)
-               o2 = opirr(ctxt, AADD) | REGTMP&31<<5 | REGTMP&31
+               o2 = olsr12u(ctxt, int32(opldr12(ctxt, int(p.As))), 0, REGTMP, int(p.To.Reg))
                rel := obj.Addrel(ctxt.Cursym)
                rel.Off = int32(ctxt.Pc)
-               rel.Siz = 8
                rel.Sym = p.From.Sym
                rel.Add = p.From.Offset
-               rel.Type = obj.R_ADDRARM64
-               o3 = olsr12u(ctxt, int32(opldr12(ctxt, int(p.As))), 0, REGTMP, int(p.To.Reg))
+               rel.Siz = 8
+               rel.Type = movereloc(p.As)
 
        case 66: /* ldp O(R)!, (r1, r2); ldp (R)O!, (r1, r2) */
                v := int32(p.From.Offset)
@@ -4161,3 +4159,19 @@ func movesize(a int) int {
                return -1
        }
 }
+
+func movereloc(a int16) int32 {
+       switch movesize(int(a)) {
+       case 0:
+               return obj.R_ARM64_LOAD8
+       case 1:
+               return obj.R_ARM64_LOAD16
+       case 2:
+               return obj.R_ARM64_LOAD32
+       case 3:
+               return obj.R_ARM64_LOAD64
+       case -1:
+               panic("xxx")
+       }
+       return -1
+}

diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index 367dc1247f8a99b6f52e511ab1bc6e61f9a19d36..9780956323e34098a76c0931b61d9730a3ed937c 100644 (file)
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -457,6 +457,11 @@ const (
        // referenced (thread local) symbol from the GOT.
        R_ARM64_TLS_IE
 
+       R_ARM64_LOAD8
+       R_ARM64_LOAD16
+       R_ARM64_LOAD32
+       R_ARM64_LOAD64
+
        // PPC64.
 
        // R_POWER_TLS_LE is used to implement the "local exec" model for tls

diff --git a/src/cmd/link/internal/arm64/asm.go b/src/cmd/link/internal/arm64/asm.go
index 7308d2fce13094c2d6f37fe075b6520ebb7c5559..8517a900049461fd3c0f3dfa14c9296befaf4e7a 100644 (file)
--- a/src/cmd/link/internal/arm64/asm.go
+++ b/src/cmd/link/internal/arm64/asm.go
@@ -82,6 +82,30 @@ func elfreloc1(r *ld.Reloc, sectoff int64) int {
                ld.Thearch.Vput(uint64(sectoff + 4))
                ld.Thearch.Vput(ld.R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC | uint64(elfsym)<<32)
 
+       case obj.R_ARM64_LOAD8:
+               ld.Thearch.Vput(ld.R_AARCH64_ADR_PREL_PG_HI21 | uint64(elfsym)<<32)
+               ld.Thearch.Vput(uint64(r.Xadd))
+               ld.Thearch.Vput(uint64(sectoff + 4))
+               ld.Thearch.Vput(ld.R_AARCH64_LDST8_ABS_LO12_NC | uint64(elfsym)<<32)
+
+       case obj.R_ARM64_LOAD16:
+               ld.Thearch.Vput(ld.R_AARCH64_ADR_PREL_PG_HI21 | uint64(elfsym)<<32)
+               ld.Thearch.Vput(uint64(r.Xadd))
+               ld.Thearch.Vput(uint64(sectoff + 4))
+               ld.Thearch.Vput(ld.R_AARCH64_LDST16_ABS_LO12_NC | uint64(elfsym)<<32)
+
+       case obj.R_ARM64_LOAD32:
+               ld.Thearch.Vput(ld.R_AARCH64_ADR_PREL_PG_HI21 | uint64(elfsym)<<32)
+               ld.Thearch.Vput(uint64(r.Xadd))
+               ld.Thearch.Vput(uint64(sectoff + 4))
+               ld.Thearch.Vput(ld.R_AARCH64_LDST32_ABS_LO12_NC | uint64(elfsym)<<32)
+
+       case obj.R_ARM64_LOAD64:
+               ld.Thearch.Vput(ld.R_AARCH64_ADR_PREL_PG_HI21 | uint64(elfsym)<<32)
+               ld.Thearch.Vput(uint64(r.Xadd))
+               ld.Thearch.Vput(uint64(sectoff + 4))
+               ld.Thearch.Vput(ld.R_AARCH64_LDST64_ABS_LO12_NC | uint64(elfsym)<<32)
+
        case obj.R_CALLARM64:
                if r.Siz != 4 {
                        return -1
@@ -178,13 +202,72 @@ func machoreloc1(r *ld.Reloc, sectoff int64) int {
        return 0
 }
 
+func archrelocaddr(r *ld.Reloc, s *ld.LSym, val *int64) int {
+       var o1, o2 uint32
+       if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
+               o1 = uint32(*val >> 32)
+               o2 = uint32(*val)
+       } else {
+               o1 = uint32(*val)
+               o2 = uint32(*val >> 32)
+       }
+
+       // We are inserting an address into two instructions: adrp and
+       // then either addi or a load.
+       address := ld.Symaddr(r.Sym) + r.Add
+       pgaddress := (address &^ 0xfff) - ((s.Value + int64(r.Off)) &^ 0xfff)
+       if pgaddress < -1<<31 || pgaddress >= 1<<31 {
+               ld.Ctxt.Diag("relocation for %s is too big (>=2G): %d", s.Name, pgaddress)
+       }
+       pgoff := uint32(address & 0xfff)
+       o1 |= uint32((((pgaddress >> 12) & 3) << 29) | (((pgaddress >> 12 >> 2) & 0x7ffff) << 5))
+
+       switch r.Type {
+       case obj.R_ADDRARM64, obj.R_ARM64_LOAD8:
+               o2 |= pgoff << 10
+
+       case obj.R_ARM64_LOAD16:
+               if pgoff&0x1 != 0 {
+                       ld.Diag("offset for 16-byte load/store has unaligned value %d", pgoff)
+               }
+               o2 |= pgoff << 9
+
+       case obj.R_ARM64_LOAD32:
+               if pgoff&0x3 != 0 {
+                       ld.Diag("offset for 32-byte load/store has unaligned value %d", pgoff)
+               }
+               o2 |= pgoff << 8
+
+       case obj.R_ARM64_LOAD64:
+               if pgoff&0x7 != 0 {
+                       ld.Diag("offset for 64-byte load/store has unaligned value %d", pgoff)
+               }
+               o2 |= pgoff << 7
+
+       default:
+               return -1
+       }
+
+       if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
+               *val = int64(o1)<<32 | int64(o2)
+       } else {
+               *val = int64(o2)<<32 | int64(o1)
+       }
+       return 0
+}
+
 func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
        if ld.Linkmode == ld.LinkExternal {
                switch r.Type {
                default:
                        return -1
 
-               case obj.R_ADDRARM64:
+               case obj.R_ADDRARM64,
+                       obj.R_ARM64_LOAD8,
+                       obj.R_ARM64_LOAD16,
+                       obj.R_ARM64_LOAD32,
+                       obj.R_ARM64_LOAD64:
+
                        r.Done = 0
 
                        // set up addend for eventual relocation via outer symbol.
@@ -253,32 +336,8 @@ func archreloc(r *ld.Reloc, s *ld.LSym, val *int64) int {
                *val = ld.Symaddr(r.Sym) + r.Add - ld.Symaddr(ld.Linklookup(ld.Ctxt, ".got", 0))
                return 0
 
-       case obj.R_ADDRARM64:
-               t := ld.Symaddr(r.Sym) + r.Add - ((s.Value + int64(r.Off)) &^ 0xfff)
-               if t >= 1<<32 || t < -1<<32 {
-                       ld.Diag("program too large, address relocation distance = %d", t)
-               }
-
-               var o0, o1 uint32
-
-               if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
-                       o0 = uint32(*val >> 32)
-                       o1 = uint32(*val)
-               } else {
-                       o0 = uint32(*val)
-                       o1 = uint32(*val >> 32)
-               }
-
-               o0 |= (uint32((t>>12)&3) << 29) | (uint32((t>>12>>2)&0x7ffff) << 5)
-               o1 |= uint32(t&0xfff) << 10
-
-               // when laid out, the instruction order must always be o1, o2.
-               if ld.Ctxt.Arch.ByteOrder == binary.BigEndian {
-                       *val = int64(o0)<<32 | int64(o1)
-               } else {
-                       *val = int64(o1)<<32 | int64(o0)
-               }
-               return 0
+       case obj.R_ADDRARM64, obj.R_ARM64_LOAD8, obj.R_ARM64_LOAD16, obj.R_ARM64_LOAD32, obj.R_ARM64_LOAD64:
+               return archrelocaddr(r, s, val)
 
        case obj.R_ARM64_TLS_LE:
                r.Done = 0

diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 80d586145eef86c0666f2fbe84f145a747049e97..8c2f9aad78c834dca630c47da74a1182c9c33ed3 100644 (file)
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -372,6 +372,10 @@ const (
        R_AARCH64_CALL26                      = 283
        R_AARCH64_ADR_PREL_PG_HI21            = 275
        R_AARCH64_ADD_ABS_LO12_NC             = 277
+       R_AARCH64_LDST8_ABS_LO12_NC           = 278
+       R_AARCH64_LDST16_ABS_LO12_NC          = 284
+       R_AARCH64_LDST32_ABS_LO12_NC          = 285
+       R_AARCH64_LDST64_ABS_LO12_NC          = 286
        R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21   = 541
        R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC = 542
        R_AARCH64_TLSLE_MOVW_TPREL_G0         = 547