ssa: SliceToArrayPointer

cl/_testrt/slice2array/in.go

@@ -0,0 +1,8 @@
+package main
+
+func main() {
+	array := [4]byte{1, 2, 3, 4}
+	ptr := (*[4]byte)(array[:])
+	println(array == *ptr)
+	println(*(*[2]byte)(array[:]) == [2]byte{1, 2})
+}

cl/_testrt/slice2array/out.ll

@@ -0,0 +1,127 @@
+; ModuleID = 'main'
+source_filename = "main"
+
+%"github.com/goplus/llgo/internal/runtime.Slice" = type { ptr, i64, i64 }
+
+@"main.init$guard" = global i1 false, align 1
+@__llgo_argc = global i32 0, align 4
+@__llgo_argv = global ptr null, align 8
+
+define void @main.init() {
+_llgo_0:
+  %0 = load i1, ptr @"main.init$guard", align 1
+  br i1 %0, label %_llgo_2, label %_llgo_1
+
+_llgo_1:                                          ; preds = %_llgo_0
+  store i1 true, ptr @"main.init$guard", align 1
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  ret void
+}
+
+define i32 @main(i32 %0, ptr %1) {
+_llgo_0:
+  store i32 %0, ptr @__llgo_argc, align 4
+  store ptr %1, ptr @__llgo_argv, align 8
+  call void @"github.com/goplus/llgo/internal/runtime.init"()
+  call void @main.init()
+  %2 = call ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64 4)
+  %3 = getelementptr inbounds i8, ptr %2, i64 0
+  %4 = getelementptr inbounds i8, ptr %2, i64 1
+  %5 = getelementptr inbounds i8, ptr %2, i64 2
+  %6 = getelementptr inbounds i8, ptr %2, i64 3
+  store i8 1, ptr %3, align 1
+  store i8 2, ptr %4, align 1
+  store i8 3, ptr %5, align 1
+  store i8 4, ptr %6, align 1
+  %7 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %8 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %7, i32 0, i32 0
+  store ptr %2, ptr %8, align 8
+  %9 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %7, i32 0, i32 1
+  store i64 4, ptr %9, align 4
+  %10 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %7, i32 0, i32 2
+  store i64 4, ptr %10, align 4
+  %11 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %7, align 8
+  %12 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %11, 1
+  %13 = icmp slt i64 %12, 4
+  br i1 %13, label %_llgo_1, label %_llgo_2
+
+_llgo_1:                                          ; preds = %_llgo_0
+  %14 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %11, 1
+  call void @"github.com/goplus/llgo/internal/runtime.PanicSliceConvert"(i64 %14, i64 4)
+  br label %_llgo_2
+
+_llgo_2:                                          ; preds = %_llgo_1, %_llgo_0
+  %15 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %11, 0
+  %16 = load [4 x i8], ptr %2, align 1
+  %17 = load [4 x i8], ptr %15, align 1
+  %18 = extractvalue [4 x i8] %16, 0
+  %19 = extractvalue [4 x i8] %17, 0
+  %20 = icmp eq i8 %18, %19
+  %21 = and i1 true, %20
+  %22 = extractvalue [4 x i8] %16, 1
+  %23 = extractvalue [4 x i8] %17, 1
+  %24 = icmp eq i8 %22, %23
+  %25 = and i1 %21, %24
+  %26 = extractvalue [4 x i8] %16, 2
+  %27 = extractvalue [4 x i8] %17, 2
+  %28 = icmp eq i8 %26, %27
+  %29 = and i1 %25, %28
+  %30 = extractvalue [4 x i8] %16, 3
+  %31 = extractvalue [4 x i8] %17, 3
+  %32 = icmp eq i8 %30, %31
+  %33 = and i1 %29, %32
+  call void @"github.com/goplus/llgo/internal/runtime.PrintBool"(i1 %33)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  %34 = alloca %"github.com/goplus/llgo/internal/runtime.Slice", align 8
+  %35 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %34, i32 0, i32 0
+  store ptr %2, ptr %35, align 8
+  %36 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %34, i32 0, i32 1
+  store i64 4, ptr %36, align 4
+  %37 = getelementptr inbounds %"github.com/goplus/llgo/internal/runtime.Slice", ptr %34, i32 0, i32 2
+  store i64 4, ptr %37, align 4
+  %38 = load %"github.com/goplus/llgo/internal/runtime.Slice", ptr %34, align 8
+  %39 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %38, 1
+  %40 = icmp slt i64 %39, 2
+  br i1 %40, label %_llgo_3, label %_llgo_4
+
+_llgo_3:                                          ; preds = %_llgo_2
+  %41 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %38, 1
+  call void @"github.com/goplus/llgo/internal/runtime.PanicSliceConvert"(i64 %41, i64 2)
+  br label %_llgo_4
+
+_llgo_4:                                          ; preds = %_llgo_3, %_llgo_2
+  %42 = extractvalue %"github.com/goplus/llgo/internal/runtime.Slice" %38, 0
+  %43 = load [2 x i8], ptr %42, align 1
+  %44 = alloca [2 x i8], align 1
+  %45 = call ptr @"github.com/goplus/llgo/internal/runtime.Zeroinit"(ptr %44, i64 2)
+  %46 = getelementptr inbounds i8, ptr %45, i64 0
+  %47 = getelementptr inbounds i8, ptr %45, i64 1
+  store i8 1, ptr %46, align 1
+  store i8 2, ptr %47, align 1
+  %48 = load [2 x i8], ptr %45, align 1
+  %49 = extractvalue [2 x i8] %43, 0
+  %50 = extractvalue [2 x i8] %48, 0
+  %51 = icmp eq i8 %49, %50
+  %52 = and i1 true, %51
+  %53 = extractvalue [2 x i8] %43, 1
+  %54 = extractvalue [2 x i8] %48, 1
+  %55 = icmp eq i8 %53, %54
+  %56 = and i1 %52, %55
+  call void @"github.com/goplus/llgo/internal/runtime.PrintBool"(i1 %56)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8 10)
+  ret i32 0
+}
+
+declare void @"github.com/goplus/llgo/internal/runtime.init"()
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.AllocZ"(i64)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PanicSliceConvert"(i64, i64)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintBool"(i1)
+
+declare void @"github.com/goplus/llgo/internal/runtime.PrintByte"(i8)
+
+declare ptr @"github.com/goplus/llgo/internal/runtime.Zeroinit"(ptr, i64)

cl/compile.go

@@ -605,6 +605,10 @@ func (p *context) compileInstrOrValue(b llssa.Builder, iv instrOrValue, asValue
 			}
 		}
 		ret = b.Select(states, v.Blocking)
+	case *ssa.SliceToArrayPointer:
+		t := b.Prog.Type(v.Type(), llssa.InGo)
+		x := p.compileValue(b, v.X)
+		ret = b.SliceToArrayPointer(x, t)
 	default:
 		panic(fmt.Sprintf("compileInstrAndValue: unknown instr - %T\n", iv))
 	}

internal/runtime/alg.go

@@ -1,3 +1,7 @@
+// Copyright 2014 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.
+
 package runtime
 
 import (

internal/runtime/errors.go

@@ -0,0 +1,116 @@
+// Copyright 2014 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.
+
+package runtime
+
+// A boundsError represents an indexing or slicing operation gone wrong.
+type boundsError struct {
+	x int64
+	y int
+	// Values in an index or slice expression can be signed or unsigned.
+	// That means we'd need 65 bits to encode all possible indexes, from -2^63 to 2^64-1.
+	// Instead, we keep track of whether x should be interpreted as signed or unsigned.
+	// y is known to be nonnegative and to fit in an int.
+	signed bool
+	code   boundsErrorCode
+}
+
+type boundsErrorCode uint8
+
+const (
+	boundsIndex boundsErrorCode = iota // s[x], 0 <= x < len(s) failed
+
+	boundsSliceAlen // s[?:x], 0 <= x <= len(s) failed
+	boundsSliceAcap // s[?:x], 0 <= x <= cap(s) failed
+	boundsSliceB    // s[x:y], 0 <= x <= y failed (but boundsSliceA didn't happen)
+
+	boundsSlice3Alen // s[?:?:x], 0 <= x <= len(s) failed
+	boundsSlice3Acap // s[?:?:x], 0 <= x <= cap(s) failed
+	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
+)
+
+// boundsErrorFmts provide error text for various out-of-bounds panics.
+// Note: if you change these strings, you should adjust the size of the buffer
+// in boundsError.Error below as well.
+var boundsErrorFmts = [...]string{
+	boundsIndex:      "index out of range [%x] with length %y",
+	boundsSliceAlen:  "slice bounds out of range [:%x] with length %y",
+	boundsSliceAcap:  "slice bounds out of range [:%x] with capacity %y",
+	boundsSliceB:     "slice bounds out of range [%x:%y]",
+	boundsSlice3Alen: "slice bounds out of range [::%x] with length %y",
+	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 array or pointer to array with length %x",
+}
+
+// boundsNegErrorFmts are overriding formats if x is negative. In this case there's no need to report y.
+var boundsNegErrorFmts = [...]string{
+	boundsIndex:      "index out of range [%x]",
+	boundsSliceAlen:  "slice bounds out of range [:%x]",
+	boundsSliceAcap:  "slice bounds out of range [:%x]",
+	boundsSliceB:     "slice bounds out of range [%x:]",
+	boundsSlice3Alen: "slice bounds out of range [::%x]",
+	boundsSlice3Acap: "slice bounds out of range [::%x]",
+	boundsSlice3B:    "slice bounds out of range [:%x:]",
+	boundsSlice3C:    "slice bounds out of range [%x::]",
+}
+
+func (e boundsError) RuntimeError() {}
+
+func appendIntStr(b []byte, v int64, signed bool) []byte {
+	if signed && v < 0 {
+		b = append(b, '-')
+		v = -v
+	}
+	var buf [20]byte
+	b = append(b, itoa(buf[:], uint64(v))...)
+	return b
+}
+
+func (e boundsError) Error() string {
+	fmt := boundsErrorFmts[e.code]
+	if e.signed && e.x < 0 {
+		fmt = boundsNegErrorFmts[e.code]
+	}
+	// max message length is 99: "runtime error: slice bounds out of range [::%x] with capacity %y"
+	// x can be at most 20 characters. y can be at most 19.
+	b := make([]byte, 0, 100)
+	b = append(b, "runtime error: "...)
+	for i := 0; i < len(fmt); i++ {
+		c := fmt[i]
+		if c != '%' {
+			b = append(b, c)
+			continue
+		}
+		i++
+		switch fmt[i] {
+		case 'x':
+			b = appendIntStr(b, e.x, e.signed)
+		case 'y':
+			b = appendIntStr(b, int64(e.y), true)
+		}
+	}
+	return string(b)
+}
+
+func itoa(buf []byte, val uint64) []byte {
+	i := len(buf) - 1
+	for val >= 10 {
+		buf[i] = byte(val%10 + '0')
+		i--
+		val /= 10
+	}
+	buf[i] = byte(val + '0')
+	return buf[i:]
+}
+
+// failures in the conversion ([x]T)(s) or (*[x]T)(s), 0 <= x <= y, y == len(s)
+func PanicSliceConvert(x int, y int) {
+	panic(boundsError{x: int64(x), signed: true, y: y, code: boundsConvert})
+}

ssa/expr.go

@@ -1030,6 +1030,34 @@ func (b Builder) compareSelect(op token.Token, x Expr, y ...Expr) Expr {
 	return ret
 }
 
+// The SliceToArrayPointer instruction yields the conversion of slice X to
+// array pointer.
+//
+// Pos() returns the ast.CallExpr.Lparen, if the instruction arose
+// from an explicit conversion in the source.
+//
+// Conversion may to be to or from a type parameter. All types in
+// the type set of X.Type() must be a slice types that can be converted to
+// all types in the type set of Type() which must all be pointer to array
+// types.
+//
+// This operation can fail dynamically if the length of the slice is less
+// than the length of the array.
+//
+// Example printed form:
+//
+//	t1 = slice to array pointer *[4]byte <- []byte (t0)
+func (b Builder) SliceToArrayPointer(x Expr, typ Type) (ret Expr) {
+	ret.Type = typ
+	max := b.Prog.IntVal(uint64(typ.RawType().Underlying().(*types.Pointer).Elem().Underlying().(*types.Array).Len()), b.Prog.Int())
+	failed := Expr{llvm.CreateICmp(b.impl, llvm.IntSLT, b.SliceLen(x).impl, max.impl), b.Prog.Bool()}
+	b.IfThen(failed, func() {
+		b.InlineCall(b.Pkg.rtFunc("PanicSliceConvert"), b.SliceLen(x), max)
+	})
+	ret.impl = b.SliceData(x).impl
+	return
+}
+
 // A Builtin represents a specific use of a built-in function, e.g. len.
 //
 // Builtins are immutable values.  Builtins do not have addresses.