cmd/compile: allow conversion from slice to array ptr

Panic if the slice is too short.

Updates #395

Change-Id: I90f4bff2da5d8f3148ba06d2482084f32b25c29a
Reviewed-on: https://go-review.googlesource.com/c/go/+/301650
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/escape/escape.go b/src/cmd/compile/internal/escape/escape.go
index 6bebe5422f83b42a7190a61f2f43608536daff8f..b706d7d2c8cd1ce722430b712262e5dbdc76be7a 100644 (file)
--- a/src/cmd/compile/internal/escape/escape.go
+++ b/src/cmd/compile/internal/escape/escape.go
@@ -669,7 +669,10 @@ func (e *escape) exprSkipInit(k hole, n ir.Node) {
                        k = e.spill(k, n)
                }
                e.expr(k.note(n, "interface-converted"), n.X)
-
+       case ir.OSLICE2ARRPTR:
+               // the slice pointer flows directly to the result
+               n := n.(*ir.ConvExpr)
+               e.expr(k, n.X)
        case ir.ORECV:
                n := n.(*ir.UnaryExpr)
                e.discard(n.X)

diff --git a/src/cmd/compile/internal/ir/expr.go b/src/cmd/compile/internal/ir/expr.go
index 112d3941ce416e2bf780d4250e37b79a3fb4dd70..a9f8c6eae5f7ac0f80ad5ba65d2a63356529e442 100644 (file)
--- a/src/cmd/compile/internal/ir/expr.go
+++ b/src/cmd/compile/internal/ir/expr.go
@@ -277,7 +277,7 @@ func (n *ConvExpr) SetOp(op Op) {
        switch op {
        default:
                panic(n.no("SetOp " + op.String()))
-       case OCONV, OCONVIFACE, OCONVNOP, OBYTES2STR, OBYTES2STRTMP, ORUNES2STR, OSTR2BYTES, OSTR2BYTESTMP, OSTR2RUNES, ORUNESTR:
+       case OCONV, OCONVIFACE, OCONVNOP, OBYTES2STR, OBYTES2STRTMP, ORUNES2STR, OSTR2BYTES, OSTR2BYTESTMP, OSTR2RUNES, ORUNESTR, OSLICE2ARRPTR:
                n.op = op
        }
 }

diff --git a/src/cmd/compile/internal/ir/fmt.go b/src/cmd/compile/internal/ir/fmt.go
index 1a05079dac8ee45b43cbb86f177aca0c2726fb77..8eb1cffc59af429d00f20a0e3208efcfd6e1c76d 100644 (file)
--- a/src/cmd/compile/internal/ir/fmt.go
+++ b/src/cmd/compile/internal/ir/fmt.go
@@ -206,6 +206,7 @@ var OpPrec = []int{
        OPRINT:         8,
        ORUNESTR:       8,
        OSIZEOF:        8,
+       OSLICE2ARRPTR:  8,
        OSTR2BYTES:     8,
        OSTR2RUNES:     8,
        OSTRUCTLIT:     8,
@@ -804,7 +805,8 @@ func exprFmt(n Node, s fmt.State, prec int) {
                ORUNES2STR,
                OSTR2BYTES,
                OSTR2RUNES,
-               ORUNESTR:
+               ORUNESTR,
+               OSLICE2ARRPTR:
                n := n.(*ConvExpr)
                if n.Type() == nil || n.Type().Sym() == nil {
                        fmt.Fprintf(s, "(%v)", n.Type())

diff --git a/src/cmd/compile/internal/ir/node.go b/src/cmd/compile/internal/ir/node.go
index b6be74296ff53fb761beb37b36b896f8e0a5b93a..b4db79e5c2959dcb162b60111a3b403e0162b84e 100644 (file)
--- a/src/cmd/compile/internal/ir/node.go
+++ b/src/cmd/compile/internal/ir/node.go
@@ -137,6 +137,7 @@ const (
        OSTR2BYTES    // Type(Left) (Type is []byte, Left is a string)
        OSTR2BYTESTMP // Type(Left) (Type is []byte, Left is a string, ephemeral)
        OSTR2RUNES    // Type(Left) (Type is []rune, Left is a string)
+       OSLICE2ARRPTR // Type(Left) (Type is *[N]T, Left is a []T)
        // Left = Right or (if Colas=true) Left := Right
        // If Colas, then Ninit includes a DCL node for Left.
        OAS

diff --git a/src/cmd/compile/internal/ir/op_string.go b/src/cmd/compile/internal/ir/op_string.go
index cfd36c7b3df543a029c480db257ef1fc35bb3052..156ffd69bad55dd8dc133ee939b4836d581a4a85 100644 (file)
--- a/src/cmd/compile/internal/ir/op_string.go
+++ b/src/cmd/compile/internal/ir/op_string.go
@@ -29,143 +29,144 @@ func _() {
        _ = x[OSTR2BYTES-18]
        _ = x[OSTR2BYTESTMP-19]
        _ = x[OSTR2RUNES-20]
-       _ = x[OAS-21]
-       _ = x[OAS2-22]
-       _ = x[OAS2DOTTYPE-23]
-       _ = x[OAS2FUNC-24]
-       _ = x[OAS2MAPR-25]
-       _ = x[OAS2RECV-26]
-       _ = x[OASOP-27]
-       _ = x[OCALL-28]
-       _ = x[OCALLFUNC-29]
-       _ = x[OCALLMETH-30]
-       _ = x[OCALLINTER-31]
-       _ = x[OCALLPART-32]
-       _ = x[OCAP-33]
-       _ = x[OCLOSE-34]
-       _ = x[OCLOSURE-35]
-       _ = x[OCOMPLIT-36]
-       _ = x[OMAPLIT-37]
-       _ = x[OSTRUCTLIT-38]
-       _ = x[OARRAYLIT-39]
-       _ = x[OSLICELIT-40]
-       _ = x[OPTRLIT-41]
-       _ = x[OCONV-42]
-       _ = x[OCONVIFACE-43]
-       _ = x[OCONVNOP-44]
-       _ = x[OCOPY-45]
-       _ = x[ODCL-46]
-       _ = x[ODCLFUNC-47]
-       _ = x[ODCLCONST-48]
-       _ = x[ODCLTYPE-49]
-       _ = x[ODELETE-50]
-       _ = x[ODOT-51]
-       _ = x[ODOTPTR-52]
-       _ = x[ODOTMETH-53]
-       _ = x[ODOTINTER-54]
-       _ = x[OXDOT-55]
-       _ = x[ODOTTYPE-56]
-       _ = x[ODOTTYPE2-57]
-       _ = x[OEQ-58]
-       _ = x[ONE-59]
-       _ = x[OLT-60]
-       _ = x[OLE-61]
-       _ = x[OGE-62]
-       _ = x[OGT-63]
-       _ = x[ODEREF-64]
-       _ = x[OINDEX-65]
-       _ = x[OINDEXMAP-66]
-       _ = x[OKEY-67]
-       _ = x[OSTRUCTKEY-68]
-       _ = x[OLEN-69]
-       _ = x[OMAKE-70]
-       _ = x[OMAKECHAN-71]
-       _ = x[OMAKEMAP-72]
-       _ = x[OMAKESLICE-73]
-       _ = x[OMAKESLICECOPY-74]
-       _ = x[OMUL-75]
-       _ = x[ODIV-76]
-       _ = x[OMOD-77]
-       _ = x[OLSH-78]
-       _ = x[ORSH-79]
-       _ = x[OAND-80]
-       _ = x[OANDNOT-81]
-       _ = x[ONEW-82]
-       _ = x[ONOT-83]
-       _ = x[OBITNOT-84]
-       _ = x[OPLUS-85]
-       _ = x[ONEG-86]
-       _ = x[OOROR-87]
-       _ = x[OPANIC-88]
-       _ = x[OPRINT-89]
-       _ = x[OPRINTN-90]
-       _ = x[OPAREN-91]
-       _ = x[OSEND-92]
-       _ = x[OSLICE-93]
-       _ = x[OSLICEARR-94]
-       _ = x[OSLICESTR-95]
-       _ = x[OSLICE3-96]
-       _ = x[OSLICE3ARR-97]
-       _ = x[OSLICEHEADER-98]
-       _ = x[ORECOVER-99]
-       _ = x[ORECV-100]
-       _ = x[ORUNESTR-101]
-       _ = x[OSELRECV2-102]
-       _ = x[OIOTA-103]
-       _ = x[OREAL-104]
-       _ = x[OIMAG-105]
-       _ = x[OCOMPLEX-106]
-       _ = x[OALIGNOF-107]
-       _ = x[OOFFSETOF-108]
-       _ = x[OSIZEOF-109]
-       _ = x[OMETHEXPR-110]
-       _ = x[OSTMTEXPR-111]
-       _ = x[OBLOCK-112]
-       _ = x[OBREAK-113]
-       _ = x[OCASE-114]
-       _ = x[OCONTINUE-115]
-       _ = x[ODEFER-116]
-       _ = x[OFALL-117]
-       _ = x[OFOR-118]
-       _ = x[OFORUNTIL-119]
-       _ = x[OGOTO-120]
-       _ = x[OIF-121]
-       _ = x[OLABEL-122]
-       _ = x[OGO-123]
-       _ = x[ORANGE-124]
-       _ = x[ORETURN-125]
-       _ = x[OSELECT-126]
-       _ = x[OSWITCH-127]
-       _ = x[OTYPESW-128]
-       _ = x[OFUNCINST-129]
-       _ = x[OTCHAN-130]
-       _ = x[OTMAP-131]
-       _ = x[OTSTRUCT-132]
-       _ = x[OTINTER-133]
-       _ = x[OTFUNC-134]
-       _ = x[OTARRAY-135]
-       _ = x[OTSLICE-136]
-       _ = x[OINLCALL-137]
-       _ = x[OEFACE-138]
-       _ = x[OITAB-139]
-       _ = x[OIDATA-140]
-       _ = x[OSPTR-141]
-       _ = x[OCFUNC-142]
-       _ = x[OCHECKNIL-143]
-       _ = x[OVARDEF-144]
-       _ = x[OVARKILL-145]
-       _ = x[OVARLIVE-146]
-       _ = x[ORESULT-147]
-       _ = x[OINLMARK-148]
-       _ = x[OLINKSYMOFFSET-149]
-       _ = x[OTAILCALL-150]
-       _ = x[OGETG-151]
-       _ = x[OEND-152]
+       _ = x[OSLICE2ARRPTR-21]
+       _ = x[OAS-22]
+       _ = x[OAS2-23]
+       _ = x[OAS2DOTTYPE-24]
+       _ = x[OAS2FUNC-25]
+       _ = x[OAS2MAPR-26]
+       _ = x[OAS2RECV-27]
+       _ = x[OASOP-28]
+       _ = x[OCALL-29]
+       _ = x[OCALLFUNC-30]
+       _ = x[OCALLMETH-31]
+       _ = x[OCALLINTER-32]
+       _ = x[OCALLPART-33]
+       _ = x[OCAP-34]
+       _ = x[OCLOSE-35]
+       _ = x[OCLOSURE-36]
+       _ = x[OCOMPLIT-37]
+       _ = x[OMAPLIT-38]
+       _ = x[OSTRUCTLIT-39]
+       _ = x[OARRAYLIT-40]
+       _ = x[OSLICELIT-41]
+       _ = x[OPTRLIT-42]
+       _ = x[OCONV-43]
+       _ = x[OCONVIFACE-44]
+       _ = x[OCONVNOP-45]
+       _ = x[OCOPY-46]
+       _ = x[ODCL-47]
+       _ = x[ODCLFUNC-48]
+       _ = x[ODCLCONST-49]
+       _ = x[ODCLTYPE-50]
+       _ = x[ODELETE-51]
+       _ = x[ODOT-52]
+       _ = x[ODOTPTR-53]
+       _ = x[ODOTMETH-54]
+       _ = x[ODOTINTER-55]
+       _ = x[OXDOT-56]
+       _ = x[ODOTTYPE-57]
+       _ = x[ODOTTYPE2-58]
+       _ = x[OEQ-59]
+       _ = x[ONE-60]
+       _ = x[OLT-61]
+       _ = x[OLE-62]
+       _ = x[OGE-63]
+       _ = x[OGT-64]
+       _ = x[ODEREF-65]
+       _ = x[OINDEX-66]
+       _ = x[OINDEXMAP-67]
+       _ = x[OKEY-68]
+       _ = x[OSTRUCTKEY-69]
+       _ = x[OLEN-70]
+       _ = x[OMAKE-71]
+       _ = x[OMAKECHAN-72]
+       _ = x[OMAKEMAP-73]
+       _ = x[OMAKESLICE-74]
+       _ = x[OMAKESLICECOPY-75]
+       _ = x[OMUL-76]
+       _ = x[ODIV-77]
+       _ = x[OMOD-78]
+       _ = x[OLSH-79]
+       _ = x[ORSH-80]
+       _ = x[OAND-81]
+       _ = x[OANDNOT-82]
+       _ = x[ONEW-83]
+       _ = x[ONOT-84]
+       _ = x[OBITNOT-85]
+       _ = x[OPLUS-86]
+       _ = x[ONEG-87]
+       _ = x[OOROR-88]
+       _ = x[OPANIC-89]
+       _ = x[OPRINT-90]
+       _ = x[OPRINTN-91]
+       _ = x[OPAREN-92]
+       _ = x[OSEND-93]
+       _ = x[OSLICE-94]
+       _ = x[OSLICEARR-95]
+       _ = x[OSLICESTR-96]
+       _ = x[OSLICE3-97]
+       _ = x[OSLICE3ARR-98]
+       _ = x[OSLICEHEADER-99]
+       _ = x[ORECOVER-100]
+       _ = x[ORECV-101]
+       _ = x[ORUNESTR-102]
+       _ = x[OSELRECV2-103]
+       _ = x[OIOTA-104]
+       _ = x[OREAL-105]
+       _ = x[OIMAG-106]
+       _ = x[OCOMPLEX-107]
+       _ = x[OALIGNOF-108]
+       _ = x[OOFFSETOF-109]
+       _ = x[OSIZEOF-110]
+       _ = x[OMETHEXPR-111]
+       _ = x[OSTMTEXPR-112]
+       _ = x[OBLOCK-113]
+       _ = x[OBREAK-114]
+       _ = x[OCASE-115]
+       _ = x[OCONTINUE-116]
+       _ = x[ODEFER-117]
+       _ = x[OFALL-118]
+       _ = x[OFOR-119]
+       _ = x[OFORUNTIL-120]
+       _ = x[OGOTO-121]
+       _ = x[OIF-122]
+       _ = x[OLABEL-123]
+       _ = x[OGO-124]
+       _ = x[ORANGE-125]
+       _ = x[ORETURN-126]
+       _ = x[OSELECT-127]
+       _ = x[OSWITCH-128]
+       _ = x[OTYPESW-129]
+       _ = x[OFUNCINST-130]
+       _ = x[OTCHAN-131]
+       _ = x[OTMAP-132]
+       _ = x[OTSTRUCT-133]
+       _ = x[OTINTER-134]
+       _ = x[OTFUNC-135]
+       _ = x[OTARRAY-136]
+       _ = x[OTSLICE-137]
+       _ = x[OINLCALL-138]
+       _ = x[OEFACE-139]
+       _ = x[OITAB-140]
+       _ = x[OIDATA-141]
+       _ = x[OSPTR-142]
+       _ = x[OCFUNC-143]
+       _ = x[OCHECKNIL-144]
+       _ = x[OVARDEF-145]
+       _ = x[OVARKILL-146]
+       _ = x[OVARLIVE-147]
+       _ = x[ORESULT-148]
+       _ = x[OINLMARK-149]
+       _ = x[OLINKSYMOFFSET-150]
+       _ = x[OTAILCALL-151]
+       _ = x[OGETG-152]
+       _ = x[OEND-153]
 }
 
-const _Op_name = "XXXNAMENONAMETYPEPACKLITERALNILADDSUBORXORADDSTRADDRANDANDAPPENDBYTES2STRBYTES2STRTMPRUNES2STRSTR2BYTESSTR2BYTESTMPSTR2RUNESASAS2AS2DOTTYPEAS2FUNCAS2MAPRAS2RECVASOPCALLCALLFUNCCALLMETHCALLINTERCALLPARTCAPCLOSECLOSURECOMPLITMAPLITSTRUCTLITARRAYLITSLICELITPTRLITCONVCONVIFACECONVNOPCOPYDCLDCLFUNCDCLCONSTDCLTYPEDELETEDOTDOTPTRDOTMETHDOTINTERXDOTDOTTYPEDOTTYPE2EQNELTLEGEGTDEREFINDEXINDEXMAPKEYSTRUCTKEYLENMAKEMAKECHANMAKEMAPMAKESLICEMAKESLICECOPYMULDIVMODLSHRSHANDANDNOTNEWNOTBITNOTPLUSNEGORORPANICPRINTPRINTNPARENSENDSLICESLICEARRSLICESTRSLICE3SLICE3ARRSLICEHEADERRECOVERRECVRUNESTRSELRECV2IOTAREALIMAGCOMPLEXALIGNOFOFFSETOFSIZEOFMETHEXPRSTMTEXPRBLOCKBREAKCASECONTINUEDEFERFALLFORFORUNTILGOTOIFLABELGORANGERETURNSELECTSWITCHTYPESWFUNCINSTTCHANTMAPTSTRUCTTINTERTFUNCTARRAYTSLICEINLCALLEFACEITABIDATASPTRCFUNCCHECKNILVARDEFVARKILLVARLIVERESULTINLMARKLINKSYMOFFSETTAILCALLGETGEND"
+const _Op_name = "XXXNAMENONAMETYPEPACKLITERALNILADDSUBORXORADDSTRADDRANDANDAPPENDBYTES2STRBYTES2STRTMPRUNES2STRSTR2BYTESSTR2BYTESTMPSTR2RUNESSLICE2ARRPTRASAS2AS2DOTTYPEAS2FUNCAS2MAPRAS2RECVASOPCALLCALLFUNCCALLMETHCALLINTERCALLPARTCAPCLOSECLOSURECOMPLITMAPLITSTRUCTLITARRAYLITSLICELITPTRLITCONVCONVIFACECONVNOPCOPYDCLDCLFUNCDCLCONSTDCLTYPEDELETEDOTDOTPTRDOTMETHDOTINTERXDOTDOTTYPEDOTTYPE2EQNELTLEGEGTDEREFINDEXINDEXMAPKEYSTRUCTKEYLENMAKEMAKECHANMAKEMAPMAKESLICEMAKESLICECOPYMULDIVMODLSHRSHANDANDNOTNEWNOTBITNOTPLUSNEGORORPANICPRINTPRINTNPARENSENDSLICESLICEARRSLICESTRSLICE3SLICE3ARRSLICEHEADERRECOVERRECVRUNESTRSELRECV2IOTAREALIMAGCOMPLEXALIGNOFOFFSETOFSIZEOFMETHEXPRSTMTEXPRBLOCKBREAKCASECONTINUEDEFERFALLFORFORUNTILGOTOIFLABELGORANGERETURNSELECTSWITCHTYPESWFUNCINSTTCHANTMAPTSTRUCTTINTERTFUNCTARRAYTSLICEINLCALLEFACEITABIDATASPTRCFUNCCHECKNILVARDEFVARKILLVARLIVERESULTINLMARKLINKSYMOFFSETTAILCALLGETGEND"
 
-var _Op_index = [...]uint16{0, 3, 7, 13, 17, 21, 28, 31, 34, 37, 39, 42, 48, 52, 58, 64, 73, 85, 94, 103, 115, 124, 126, 129, 139, 146, 153, 160, 164, 168, 176, 184, 193, 201, 204, 209, 216, 223, 229, 238, 246, 254, 260, 264, 273, 280, 284, 287, 294, 302, 309, 315, 318, 324, 331, 339, 343, 350, 358, 360, 362, 364, 366, 368, 370, 375, 380, 388, 391, 400, 403, 407, 415, 422, 431, 444, 447, 450, 453, 456, 459, 462, 468, 471, 474, 480, 484, 487, 491, 496, 501, 507, 512, 516, 521, 529, 537, 543, 552, 563, 570, 574, 581, 589, 593, 597, 601, 608, 615, 623, 629, 637, 645, 650, 655, 659, 667, 672, 676, 679, 687, 691, 693, 698, 700, 705, 711, 717, 723, 729, 737, 742, 746, 753, 759, 764, 770, 776, 783, 788, 792, 797, 801, 806, 814, 820, 827, 834, 840, 847, 860, 868, 872, 875}
+var _Op_index = [...]uint16{0, 3, 7, 13, 17, 21, 28, 31, 34, 37, 39, 42, 48, 52, 58, 64, 73, 85, 94, 103, 115, 124, 136, 138, 141, 151, 158, 165, 172, 176, 180, 188, 196, 205, 213, 216, 221, 228, 235, 241, 250, 258, 266, 272, 276, 285, 292, 296, 299, 306, 314, 321, 327, 330, 336, 343, 351, 355, 362, 370, 372, 374, 376, 378, 380, 382, 387, 392, 400, 403, 412, 415, 419, 427, 434, 443, 456, 459, 462, 465, 468, 471, 474, 480, 483, 486, 492, 496, 499, 503, 508, 513, 519, 524, 528, 533, 541, 549, 555, 564, 575, 582, 586, 593, 601, 605, 609, 613, 620, 627, 635, 641, 649, 657, 662, 667, 671, 679, 684, 688, 691, 699, 703, 705, 710, 712, 717, 723, 729, 735, 741, 749, 754, 758, 765, 771, 776, 782, 788, 795, 800, 804, 809, 813, 818, 826, 832, 839, 846, 852, 859, 872, 880, 884, 887}
 
 func (i Op) String() string {
        if i >= Op(len(_Op_index)-1) {

diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go
index be460457a8b71fa46df5978056788827f2e0c2a4..46c2388e7b8f085002bde5d196b24b3970a889ba 100644 (file)
--- a/src/cmd/compile/internal/ssa/expand_calls.go
+++ b/src/cmd/compile/internal/ssa/expand_calls.go
@@ -508,7 +508,7 @@ func (x *expandState) rewriteSelect(leaf *Value, selector *Value, offset int64,
                ls := x.rewriteSelect(leaf, selector.Args[0], offset, regOffset)
                locs = x.splitSlots(ls, ".ptr", 0, x.typs.BytePtr)
 
-       case OpSlicePtr:
+       case OpSlicePtr, OpSlicePtrUnchecked:
                w := selector.Args[0]
                ls := x.rewriteSelect(leaf, w, offset, regOffset)
                locs = x.splitSlots(ls, ".ptr", 0, types.NewPtr(w.Type.Elem()))
@@ -1202,7 +1202,7 @@ func expandCalls(f *Func) {
                        case OpStructSelect, OpArraySelect,
                                OpIData, OpITab,
                                OpStringPtr, OpStringLen,
-                               OpSlicePtr, OpSliceLen, OpSliceCap,
+                               OpSlicePtr, OpSliceLen, OpSliceCap, OpSlicePtrUnchecked,
                                OpComplexReal, OpComplexImag,
                                OpInt64Hi, OpInt64Lo:
                                w := v.Args[0]

diff --git a/src/cmd/compile/internal/ssa/gen/dec.rules b/src/cmd/compile/internal/ssa/gen/dec.rules
index 4c677f8418f61b9e5192c05e7290c0015ad27e13..b19489870dde044f2e93753b6cb2a502937ad340 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/dec.rules
+++ b/src/cmd/compile/internal/ssa/gen/dec.rules
@@ -56,6 +56,7 @@
 (SlicePtr (SliceMake ptr _ _ )) => ptr
 (SliceLen (SliceMake _ len _)) => len
 (SliceCap (SliceMake _ _ cap)) => cap
+(SlicePtrUnchecked (SliceMake ptr _ _ )) => ptr
 
 (Load <t> ptr mem) && t.IsSlice() =>
   (SliceMake

diff --git a/src/cmd/compile/internal/ssa/gen/genericOps.go b/src/cmd/compile/internal/ssa/gen/genericOps.go
index c38d22e07f5ac24563e0f0dc1e89d045c252d0ea..9f6664386c9d1749e51c4d6bd3a29c6fecd7d37d 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/genericOps.go
+++ b/src/cmd/compile/internal/ssa/gen/genericOps.go
@@ -479,6 +479,10 @@ var genericOps = []opData{
        {name: "SlicePtr", argLength: 1, typ: "BytePtr"}, // ptr(arg0)
        {name: "SliceLen", argLength: 1},                 // len(arg0)
        {name: "SliceCap", argLength: 1},                 // cap(arg0)
+       // SlicePtrUnchecked, like SlicePtr, extracts the pointer from a slice.
+       // SlicePtr values are assumed non-nil, because they are guarded by bounds checks.
+       // SlicePtrUnchecked values can be nil.
+       {name: "SlicePtrUnchecked", argLength: 1},
 
        // Complex (part/whole)
        {name: "ComplexMake", argLength: 2}, // arg0=real, arg1=imag

diff --git a/src/cmd/compile/internal/ssa/op.go b/src/cmd/compile/internal/ssa/op.go
index b99a7a6646286c49759eef9d49efc1394f7250a4..f09a08abcf752102944a3aba872105ac9ebe392d 100644 (file)
--- a/src/cmd/compile/internal/ssa/op.go
+++ b/src/cmd/compile/internal/ssa/op.go
@@ -469,6 +469,7 @@ const (
        BoundsSlice3BU                      // ... with unsigned high
        BoundsSlice3C                       // 3-arg slicing operation, 0 <= low <= high failed
        BoundsSlice3CU                      // ... with unsigned low
+       BoundsConvert                       // conversion to array pointer failed
        BoundsKindCount
 )
 
@@ -496,7 +497,8 @@ func boundsABI(b int64) int {
        case BoundsSlice3Alen,
                BoundsSlice3AlenU,
                BoundsSlice3Acap,
-               BoundsSlice3AcapU:
+               BoundsSlice3AcapU,
+               BoundsConvert:
                return 0
        case BoundsSliceAlen,
                BoundsSliceAlenU,

diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 8c753ea2a3c8f102acfbceea4b80f423ac2ad3ba..2f5662539724263be9b3c7c3f4638a613fa416c5 100644 (file)
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -2834,6 +2834,7 @@ const (
        OpSlicePtr
        OpSliceLen
        OpSliceCap
+       OpSlicePtrUnchecked
        OpComplexMake
        OpComplexReal
        OpComplexImag
@@ -35898,6 +35899,11 @@ var opcodeTable = [...]opInfo{
                argLen:  1,
                generic: true,
        },
+       {
+               name:    "SlicePtrUnchecked",
+               argLen:  1,
+               generic: true,
+       },
        {
                name:    "ComplexMake",
                argLen:  2,

diff --git a/src/cmd/compile/internal/ssa/rewritedec.go b/src/cmd/compile/internal/ssa/rewritedec.go
index 4b7db60551aee0b8eaaad89a819753202ff39b4a..2a73a5ddc830d3885c6a36f02232b380917213c5 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewritedec.go
+++ b/src/cmd/compile/internal/ssa/rewritedec.go
@@ -23,6 +23,8 @@ func rewriteValuedec(v *Value) bool {
                return rewriteValuedec_OpSliceLen(v)
        case OpSlicePtr:
                return rewriteValuedec_OpSlicePtr(v)
+       case OpSlicePtrUnchecked:
+               return rewriteValuedec_OpSlicePtrUnchecked(v)
        case OpStore:
                return rewriteValuedec_OpStore(v)
        case OpStringLen:
@@ -248,6 +250,20 @@ func rewriteValuedec_OpSlicePtr(v *Value) bool {
        }
        return false
 }
+func rewriteValuedec_OpSlicePtrUnchecked(v *Value) bool {
+       v_0 := v.Args[0]
+       // match: (SlicePtrUnchecked (SliceMake ptr _ _ ))
+       // result: ptr
+       for {
+               if v_0.Op != OpSliceMake {
+                       break
+               }
+               ptr := v_0.Args[0]
+               v.copyOf(ptr)
+               return true
+       }
+       return false
+}
 func rewriteValuedec_OpStore(v *Value) bool {
        v_2 := v.Args[2]
        v_1 := v.Args[1]

diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index c5b1ae2e4a801087d4cc66c60fba85cb1e7217b1..10f02fc9871f35a315f2f6e58d3262c643f0968b 100644 (file)
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -164,6 +164,7 @@ func InitConfig() {
                BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
                BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
                BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
+               BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
        } else {
                BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("panicIndex")
                BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("panicIndexU")
@@ -181,6 +182,7 @@ func InitConfig() {
                BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("panicSlice3BU")
                BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("panicSlice3C")
                BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("panicSlice3CU")
+               BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("panicSliceConvert")
        }
        if Arch.LinkArch.PtrSize == 4 {
                ExtendCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeVar("panicExtendIndex")
@@ -3148,6 +3150,18 @@ func (s *state) expr(n ir.Node) *ssa.Value {
                p, l, _ := s.slice(v, i, j, nil, n.Bounded())
                return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
 
+       case ir.OSLICE2ARRPTR:
+               // if arrlen > slice.len {
+               //   panic(...)
+               // }
+               // slice.ptr
+               n := n.(*ir.ConvExpr)
+               v := s.expr(n.X)
+               arrlen := s.constInt(types.Types[types.TINT], n.Type().Elem().NumElem())
+               cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
+               s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
+               return s.newValue1(ssa.OpSlicePtrUnchecked, types.Types[types.TINT], v)
+
        case ir.OCALLFUNC:
                n := n.(*ir.CallExpr)
                if ir.IsIntrinsicCall(n) {

diff --git a/src/cmd/compile/internal/typecheck/builtin.go b/src/cmd/compile/internal/typecheck/builtin.go
index d83791df8bd058fc1486b7f18afcade1ea100f56..0631a67780d6818da3272fb4531549ed43b8c242 100644 (file)
--- a/src/cmd/compile/internal/typecheck/builtin.go
+++ b/src/cmd/compile/internal/typecheck/builtin.go
@@ -39,6 +39,7 @@ var runtimeDecls = [...]struct {
        {"goPanicSlice3BU", funcTag, 18},
        {"goPanicSlice3C", funcTag, 16},
        {"goPanicSlice3CU", funcTag, 18},
+       {"goPanicSliceConvert", funcTag, 16},
        {"printbool", funcTag, 19},
        {"printfloat", funcTag, 21},
        {"printint", funcTag, 23},

diff --git a/src/cmd/compile/internal/typecheck/builtin/runtime.go b/src/cmd/compile/internal/typecheck/builtin/runtime.go
index 183ae40456ad71c4e7d4e8608c2e63c26eb34a6a..e736f913b6fefc79e72714fb096d9448ef8d9d71 100644 (file)
--- a/src/cmd/compile/internal/typecheck/builtin/runtime.go
+++ b/src/cmd/compile/internal/typecheck/builtin/runtime.go
@@ -46,6 +46,7 @@ func goPanicSlice3B(x int, y int)
 func goPanicSlice3BU(x uint, y int)
 func goPanicSlice3C(x int, y int)
 func goPanicSlice3CU(x uint, y int)
+func goPanicSliceConvert(x int, y int)
 
 func printbool(bool)
 func printfloat(float64)

diff --git a/src/cmd/compile/internal/typecheck/subr.go b/src/cmd/compile/internal/typecheck/subr.go
index 76c565ebee127ca42128ec9060269cafca1f540b..9ee7a94b1f24af5bea061042a8d471c8c4758b69 100644 (file)
--- a/src/cmd/compile/internal/typecheck/subr.go
+++ b/src/cmd/compile/internal/typecheck/subr.go
@@ -574,7 +574,7 @@ func Convertop(srcConstant bool, src, dst *types.Type) (ir.Op, string) {
                return ir.OCONVNOP, ""
        }
 
-       // src is map and dst is a pointer to corresponding hmap.
+       // 10. src is map and dst is a pointer to corresponding hmap.
        // This rule is needed for the implementation detail that
        // go gc maps are implemented as a pointer to a hmap struct.
        if src.Kind() == types.TMAP && dst.IsPtr() &&
@@ -582,6 +582,16 @@ func Convertop(srcConstant bool, src, dst *types.Type) (ir.Op, string) {
                return ir.OCONVNOP, ""
        }
 
+       // 11. src is a slice and dst is a pointer-to-array.
+       // They must have same element type.
+       if src.IsSlice() && dst.IsPtr() && dst.Elem().IsArray() &&
+               types.Identical(src.Elem(), dst.Elem().Elem()) {
+               if !types.AllowsGoVersion(curpkg(), 1, 17) {
+                       return ir.OXXX, ":\n\tconversion of slices to array pointers only supported as of -lang=go1.17"
+               }
+               return ir.OSLICE2ARRPTR, ""
+       }
+
        return ir.OXXX, ""
 }
 

diff --git a/src/cmd/compile/internal/types2/api_test.go b/src/cmd/compile/internal/types2/api_test.go
index b3b16131ceb39480d96ac431f825a22709126e5f..68048f28d3cb0b92dca6a0fba42fdf4088afdc7f 100644 (file)
--- a/src/cmd/compile/internal/types2/api_test.go
+++ b/src/cmd/compile/internal/types2/api_test.go
@@ -1578,6 +1578,9 @@ func TestConvertibleTo(t *testing.T) {
                {newDefined(new(Struct)), new(Struct), true},
                {newDefined(Typ[Int]), new(Struct), false},
                {Typ[UntypedInt], Typ[Int], true},
+               {NewSlice(Typ[Int]), NewPointer(NewArray(Typ[Int], 10)), true},
+               {NewSlice(Typ[Int]), NewArray(Typ[Int], 10), false},
+               {NewSlice(Typ[Int]), NewPointer(NewArray(Typ[Uint], 10)), false},
                // Untyped string values are not permitted by the spec, so the below
                // behavior is undefined.
                {Typ[UntypedString], Typ[String], true},

diff --git a/src/cmd/compile/internal/types2/conversions.go b/src/cmd/compile/internal/types2/conversions.go
index eabed7ba9b5dbca9ddfe0b024244bf2d18d7b76e..51be50e9ad1d2c0794b7f5ea7e9438b044497513 100644 (file)
--- a/src/cmd/compile/internal/types2/conversions.go
+++ b/src/cmd/compile/internal/types2/conversions.go
@@ -135,6 +135,18 @@ func (x *operand) convertibleTo(check *Checker, T Type) bool {
                return true
        }
 
+       // "x is a slice, T is a pointer-to-array type,
+       // and the slice and array types have identical element types."
+       if s := asSlice(V); s != nil {
+               if p := asPointer(T); p != nil {
+                       if a := asArray(p.Elem()); a != nil {
+                               if check.identical(s.Elem(), a.Elem()) {
+                                       return true
+                               }
+                       }
+               }
+       }
+
        return false
 }
 

diff --git a/src/cmd/compile/internal/walk/expr.go b/src/cmd/compile/internal/walk/expr.go
index 6affbd4aece743e950f2b2d668ec056d1943e2ee..a50473db52d26649d61b401f57e9590678f816f2 100644 (file)
--- a/src/cmd/compile/internal/walk/expr.go
+++ b/src/cmd/compile/internal/walk/expr.go
@@ -205,6 +205,11 @@ func walkExpr1(n ir.Node, init *ir.Nodes) ir.Node {
                n := n.(*ir.ConvExpr)
                return walkConv(n, init)
 
+       case ir.OSLICE2ARRPTR:
+               n := n.(*ir.ConvExpr)
+               n.X = walkExpr(n.X, init)
+               return n
+
        case ir.ODIV, ir.OMOD:
                n := n.(*ir.BinaryExpr)
                return walkDivMod(n, init)

diff --git a/src/go/types/stdlib_test.go b/src/go/types/stdlib_test.go
index 29f71137df8394256a7770186f40ece33692ae7b..8f9218c864aebfce3e7301667fa6e5a0977d06af 100644 (file)
--- a/src/go/types/stdlib_test.go
+++ b/src/go/types/stdlib_test.go
@@ -163,6 +163,10 @@ func TestStdTest(t *testing.T) {
                "embedfunc.go",   // tests //go:embed
                "embedvers.go",   // tests //go:embed
                "linkname2.go",   // go/types doesn't check validity of //go:xxx directives
+
+               "convert2.go",     // temporary: go/types doesn't know yet about converting from slices to array pointers
+               "convert4.go",     // temporary: go/types doesn't know yet about converting from slices to array pointers
+               "escape_slice.go", // temporary: go/types doesn't know yet about converting from slices to array pointers
        )
 }
 

diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index 5cf6827c210554f72df57f875041bb51b1912664..45f8bf1003ec19fdfd180155ca39a23cf9410e92 100644 (file)
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -1473,6 +1473,10 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-8
        MOVL    AX, x+0(FP)
        MOVL    CX, y+4(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-8
+       MOVL    DX, x+0(FP)
+       MOVL    BX, y+4(FP)
+       JMP     runtime·goPanicSliceConvert(SB)
 
 // Extended versions for 64-bit indexes.
 TEXT runtime·panicExtendIndex(SB),NOSPLIT,$0-12

diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 1e6d8189c97a70d18138aa342e90b39014f59720..d2848e5a451f6123373b634d92e4d1c121d8a5a1 100644 (file)
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -2091,6 +2091,14 @@ TEXT runtime·panicSlice3CU<ABIInternal>(SB),NOSPLIT,$0-16
        MOVQ    CX, y+8(FP)
 #endif
        JMP     runtime·goPanicSlice3CU<ABIInternal>(SB)
+TEXT runtime·panicSliceConvert<ABIInternal>(SB),NOSPLIT,$0-16
+#ifdef GOEXPERIMENT_regabiargs
+       MOVQ    DX, AX
+#else
+       MOVQ    DX, x+0(FP)
+       MOVQ    BX, y+8(FP)
+#endif
+       JMP     runtime·goPanicSliceConvert<ABIInternal>(SB)
 
 #ifdef GOOS_android
 // Use the free TLS_SLOT_APP slot #2 on Android Q.

diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index 9896ab4383fe173ebc343255dc3ed918e86ac2da..f468b77ee3487041b464f44b5f51f43407d846ab 100644 (file)
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -992,6 +992,10 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-8
        MOVW    R0, x+0(FP)
        MOVW    R1, y+4(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-8
+       MOVW    R2, x+0(FP)
+       MOVW    R3, y+4(FP)
+       JMP     runtime·goPanicSliceConvert(SB)
 
 // Extended versions for 64-bit indexes.
 TEXT runtime·panicExtendIndex(SB),NOSPLIT,$0-12

diff --git a/src/runtime/asm_arm64.s b/src/runtime/asm_arm64.s
index 2e120dcf1eba7ba8963b99ae0779734f67afaad6..2d495397a8d0aea274a68290fe24584141f202b7 100644 (file)
--- a/src/runtime/asm_arm64.s
+++ b/src/runtime/asm_arm64.s
@@ -1314,3 +1314,7 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
        MOVD    R0, x+0(FP)
        MOVD    R1, y+8(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
+       MOVD    R2, x+0(FP)
+       MOVD    R3, y+8(FP)
+       JMP     runtime·goPanicSliceConvert(SB)

diff --git a/src/runtime/asm_mips64x.s b/src/runtime/asm_mips64x.s
index cee4b528bb9534c2daaa64fe1d405f856955782c..c3b57e472a2412187f3c103f94d8c7ef28ebf273 100644 (file)
--- a/src/runtime/asm_mips64x.s
+++ b/src/runtime/asm_mips64x.s
@@ -805,3 +805,7 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
        MOVV    R1, x+0(FP)
        MOVV    R2, y+8(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
+       MOVV    R3, x+0(FP)
+       MOVV    R4, y+8(FP)
+       JMP     runtime·goPanicSliceConvert(SB)

diff --git a/src/runtime/asm_mipsx.s b/src/runtime/asm_mipsx.s
index 17fbc902c22306f1ac74d54b5f1a8b329aa9ca7c..1d828b03cfb1e2e59cedf43b51a274fc956ab157 100644 (file)
--- a/src/runtime/asm_mipsx.s
+++ b/src/runtime/asm_mipsx.s
@@ -801,6 +801,10 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-8
        MOVW    R1, x+0(FP)
        MOVW    R2, y+4(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-8
+       MOVW    R3, x+0(FP)
+       MOVW    R4, y+4(FP)
+       JMP     runtime·goPanicSliceConvert(SB)
 
 // Extended versions for 64-bit indexes.
 TEXT runtime·panicExtendIndex(SB),NOSPLIT,$0-12

diff --git a/src/runtime/asm_ppc64x.s b/src/runtime/asm_ppc64x.s
index 65440484975d23392a2dfca832c109d69d32b726..2c39b38912f3f3badbd19fc3381ab12593648c28 100644 (file)
--- a/src/runtime/asm_ppc64x.s
+++ b/src/runtime/asm_ppc64x.s
@@ -1022,3 +1022,7 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
        MOVD    R3, x+0(FP)
        MOVD    R4, y+8(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
+       MOVD    R5, x+0(FP)
+       MOVD    R6, y+8(FP)
+       JMP     runtime·goPanicSliceConvert(SB)

diff --git a/src/runtime/asm_riscv64.s b/src/runtime/asm_riscv64.s
index d8d5252ed5bc8479051fb95d0dc77e99bc17a0bb..ef7af4e10d8826861804362f3604310ca570a584 100644 (file)
--- a/src/runtime/asm_riscv64.s
+++ b/src/runtime/asm_riscv64.s
@@ -806,6 +806,10 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
        MOV     T0, x+0(FP)
        MOV     T1, y+8(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
+       MOV     T2, x+0(FP)
+       MOV     T3, y+8(FP)
+       JMP     runtime·goPanicSliceConvert(SB)
 
 DATA   runtime·mainPC+0(SB)/8,$runtime·main(SB)
 GLOBL  runtime·mainPC(SB),RODATA,$8

diff --git a/src/runtime/asm_s390x.s b/src/runtime/asm_s390x.s
index 4748e00aa81b243dbac90167a20e80114a4f77dc..fb382716303b42a6647b729be116512d1355bedd 100644 (file)
--- a/src/runtime/asm_s390x.s
+++ b/src/runtime/asm_s390x.s
@@ -906,3 +906,7 @@ TEXT runtime·panicSlice3CU(SB),NOSPLIT,$0-16
        MOVD    R0, x+0(FP)
        MOVD    R1, y+8(FP)
        JMP     runtime·goPanicSlice3CU(SB)
+TEXT runtime·panicSliceConvert(SB),NOSPLIT,$0-16
+       MOVD    R2, x+0(FP)
+       MOVD    R3, y+8(FP)
+       JMP     runtime·goPanicSliceConvert(SB)

diff --git a/src/runtime/error.go b/src/runtime/error.go
index 9e6cdf35dd39add79a4a05a1a46c1055de0c7283..91f83ae126405c4f2915c9364d6305d811d794f8 100644 (file)
--- a/src/runtime/error.go
+++ b/src/runtime/error.go
@@ -134,6 +134,7 @@ const (
        boundsSlice3B    // s[?:x:y], 0 <= x <= y failed (but boundsSlice3A didn't happen)
        boundsSlice3C    // s[x:y:?], 0 <= x <= y failed (but boundsSlice3A/B didn't happen)
 
+       boundsConvert // (*[x]T)(s), 0 <= x <= len(s) failed
        // Note: in the above, len(s) and cap(s) are stored in y
 )
 
@@ -149,6 +150,7 @@ var boundsErrorFmts = [...]string{
        boundsSlice3Acap: "slice bounds out of range [::%x] with capacity %y",
        boundsSlice3B:    "slice bounds out of range [:%x:%y]",
        boundsSlice3C:    "slice bounds out of range [%x:%y:]",
+       boundsConvert:    "cannot convert slice with length %y to pointer to array with length %x",
 }
 
 // boundsNegErrorFmts are overriding formats if x is negative. In this case there's no need to report y.

diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index f8f2f39dbb4534d5f62e9869dc02bf57b86b2ed0..f6c38aafcc825d30f55a92832ff10bf64de8c993 100644 (file)
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -160,6 +160,12 @@ func goPanicSlice3CU(x uint, y int) {
        panic(boundsError{x: int64(x), signed: false, y: y, code: boundsSlice3C})
 }
 
+// failures in the conversion (*[x]T)s, 0 <= x <= y, x == cap(s)
+func goPanicSliceConvert(x int, y int) {
+       panicCheck1(getcallerpc(), "slice length too short to convert to pointer to array")
+       panic(boundsError{x: int64(x), signed: true, y: y, code: boundsConvert})
+}
+
 // Implemented in assembly, as they take arguments in registers.
 // Declared here to mark them as ABIInternal.
 func panicIndex(x int, y int)
@@ -178,6 +184,7 @@ func panicSlice3B(x int, y int)
 func panicSlice3BU(x uint, y int)
 func panicSlice3C(x int, y int)
 func panicSlice3CU(x uint, y int)
+func panicSliceConvert(x int, y int)
 
 var shiftError = error(errorString("negative shift amount"))
 

diff --git a/test/convert2.go b/test/convert2.go
index e7044b24530eb70dc7e2045e1da11910a7bf72eb..8e43967aaaea5796b5e4ffe725e639013594957f 100644 (file)
--- a/test/convert2.go
+++ b/test/convert2.go
@@ -313,3 +313,17 @@ func _() {
        t = u       // ERROR "cannot use .* in assignment|incompatible type"
        t = (*T)(u) // ERROR "cannot convert"
 }
+
+func _() {
+       var s []byte
+       _ = ([4]byte)(s) // ERROR "cannot convert"
+       _ = (*[4]byte)(s)
+
+       type A [4]byte
+       _ = (A)(s) // ERROR "cannot convert"
+       _ = (*A)(s)
+
+       type P *[4]byte
+       _ = (P)(s)
+       _ = (*P)(s) // ERROR "cannot convert"
+}

diff --git a/test/convert4.go b/test/convert4.go
new file mode 100644 (file)
index 0000000..2bc9c96
--- /dev/null
+++ b/test/convert4.go
@@ -0,0 +1,86 @@
+// run
+
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test conversion from slice to array pointer.
+
+package main
+
+func wantPanic(fn func(), s string) {
+       defer func() {
+               err := recover()
+               if err == nil {
+                       panic("expected panic")
+               }
+               if got := err.(error).Error(); got != s {
+                       panic("expected panic " + s + " got " + got)
+               }
+       }()
+       fn()
+}
+
+func main() {
+       s := make([]byte, 8, 10)
+       if p := (*[8]byte)(s); &p[0] != &s[0] {
+               panic("*[8]byte conversion failed")
+       }
+       wantPanic(
+               func() {
+                       _ = (*[9]byte)(s)
+               },
+               "runtime error: cannot convert slice with length 8 to pointer to array with length 9",
+       )
+
+       var n []byte
+       if p := (*[0]byte)(n); p != nil {
+               panic("nil slice converted to *[0]byte should be nil")
+       }
+
+       z := make([]byte, 0)
+       if p := (*[0]byte)(z); p == nil {
+               panic("empty slice converted to *[0]byte should be non-nil")
+       }
+
+       // Test with named types
+       type Slice []int
+       type Int4 [4]int
+       type PInt4 *[4]int
+       ii := make(Slice, 4)
+       if p := (*Int4)(ii); &p[0] != &ii[0] {
+               panic("*Int4 conversion failed")
+       }
+       if p := PInt4(ii); &p[0] != &ii[0] {
+               panic("PInt4 conversion failed")
+       }
+}
+
+// test static variable conversion
+
+var (
+       ss  = make([]string, 10)
+       s5  = (*[5]string)(ss)
+       s10 = (*[10]string)(ss)
+
+       ns  []string
+       ns0 = (*[0]string)(ns)
+
+       zs  = make([]string, 0)
+       zs0 = (*[0]string)(zs)
+)
+
+func init() {
+       if &ss[0] != &s5[0] {
+               panic("s5 conversion failed")
+       }
+       if &ss[0] != &s10[0] {
+               panic("s5 conversion failed")
+       }
+       if ns0 != nil {
+               panic("ns0 should be nil")
+       }
+       if zs0 == nil {
+               panic("zs0 should not be nil")
+       }
+}

diff --git a/test/escape_slice.go b/test/escape_slice.go
index 6ce852e9c552bad8a5de053f04185b750733735f..d60414736c38d28c2527db8d21a1dba7be40983b 100644 (file)
--- a/test/escape_slice.go
+++ b/test/escape_slice.go
@@ -101,6 +101,10 @@ func slice11() {
        _ = s
 }
 
+func slice12(x []int) *[1]int { // ERROR "leaking param: x to result ~r1 level=0$"
+       return (*[1]int)(x)
+}
+
 func envForDir(dir string) []string { // ERROR "dir does not escape"
        env := os.Environ()
        return mergeEnvLists([]string{"PWD=" + dir}, env) // ERROR ".PWD=. \+ dir escapes to heap" "\[\]string{...} does not escape"