fix slice after slice a slice

compiler/compiler/slice.go

@@ -99,40 +99,39 @@ func (c *Compiler) compileSubstring(src value.Value, v *parser.SliceArrayNode) v
 
 func (c *Compiler) compileSliceArray(src value.Value, v *parser.SliceArrayNode, isSliceSlice bool) value.Value {
 	sliceType := internal.Slice(src.Type.LLVM())
-	// array pointer as receiver, do nothing
-	// type B [1]byte
-	// func (b *B) foo() {}
-	_, isSrcArray := src.Value.Type().(*llvmTypes.ArrayType)
-
 	alloc := c.contextBlock.NewAlloca(sliceType)
-
+	// actual start index = old offset + new start index
 	startIndexValue := c.compileValue(v.Start)
 	startIndex := internal.LoadIfVariable(c.contextBlock, startIndexValue)
 	offsetBefore := llvmValue.Value(constant.NewInt(llvmTypes.I32, 0))
+	if isSliceSlice {
+		offsetBefore = c.contextBlock.NewExtractValue(src.Value, 2)
+	}
+	if startIndex.Type() != llvmTypes.I64 {
+		startIndex = c.contextBlock.NewZExt(startIndex, i64.LLVM())
+	}
+	if offsetBefore.Type() != llvmTypes.I64 {
+		offsetBefore = c.contextBlock.NewZExt(offsetBefore, i64.LLVM())
+	}
+	startIndex = c.contextBlock.NewAdd(startIndex, offsetBefore)
+	// end index
 	var endIndexValue value.Value
 	if v.HasEnd {
 		endIndexValue = c.compileValue(v.End)
 	} else {
 		srcVal := src.Value
 		if isSliceSlice {
 			endIndexValue.Value = c.contextBlock.NewExtractValue(srcVal, 0)
-			offsetBefore = c.contextBlock.NewExtractValue(srcVal, 2)
 		} else {
 			arrTy := src.Type.LLVM().(*llvmTypes.ArrayType)
 			endIndexValue.Value = constant.NewInt(llvmTypes.I32, int64(arrTy.Len))
 		}
 	}
-	if startIndex.Type() != llvmTypes.I64 {
-		startIndex = c.contextBlock.NewZExt(startIndex, i64.LLVM())
-	}
-	if offsetBefore.Type() != llvmTypes.I64 {
-		offsetBefore = c.contextBlock.NewZExt(offsetBefore, i64.LLVM())
-	}
-	startIndex = c.contextBlock.NewAdd(startIndex, offsetBefore)
 	endIndex := internal.LoadIfVariable(c.contextBlock, endIndexValue)
 	if endIndex.Type() != llvmTypes.I64 {
 		endIndex = c.contextBlock.NewZExt(endIndex, i64.LLVM())
 	}
+	// len
 	sliceLen := c.contextBlock.NewSub(endIndex, startIndex)
 	var sliceLen32 llvmValue.Value
 	sliceLen32 = sliceLen
@@ -171,6 +170,10 @@ func (c *Compiler) compileSliceArray(src value.Value, v *parser.SliceArrayNode,
 	backingArrayItem.SetName(name.Var("backing"))
 
 	itemPtr := src.Value
+	// array pointer as receiver, do nothing
+	// type B [1]byte
+	// func (b *B) foo() {}
+	_, isSrcArray := src.Value.Type().(*llvmTypes.ArrayType)
 	if !isSrcArray {
 		itemPtr = c.contextBlock.NewExtractValue(src.Value, 3)
 	}

tests/examples/make-slice.cell

@@ -20,5 +20,28 @@ func main() {
 			return 1
 		}
 	}
+	a := []byte{'0','1','2','3','4','5','6','7'}
+	b := a[3:7] // 3 4 5 6
+	okb := []byte{'3', '4', '5', '6'}
+	if len(b) != len(okb) {
+		return 1
+	}
+	for i, v := range b {
+		if v != okb[i] {
+			return 2
+		}
+	}
+	c := b[0:2] // 3 4
+	okc := []byte{'3', '4'}
+	if len(c) != len(okc) {
+		return 3
+	}
+	for i, v := range c {
+		if v != okc[i] {
+			return 4
+		}
+	}
+	debug.Printf("%d%d",b[0], c[0])
+	debug.Printf("%d%d",b[0], c[0])
 	return 0
 }