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transform: PtrToInt and IntToPtr do not escape #4889

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transform: PtrToInt and IntToPtr do not escape #4889

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4 changes: 4 additions & 0 deletions transform/allocs.go
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Original file line number Diff line number Diff line change
Expand Up @@ -160,6 +160,10 @@ func valueEscapesAt(value llvm.Value) llvm.Value {
case llvm.ICmp:
// Comparing pointers don't let the pointer escape.
// This is often a compiler-inserted nil check.
case llvm.PtrToInt:
// Pointer to int conversion doesn't let the pointer escape.
case llvm.IntToPtr:
// Int to pointer conversion doesn't let the pointer escape.
default:
// Unknown instruction, might escape.
return use
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23 changes: 15 additions & 8 deletions transform/testdata/allocs2.go
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Original file line number Diff line number Diff line change
@@ -1,11 +1,13 @@
package main

import "unsafe"

func main() {
n1 := 5
derefInt(&n1)

// This should eventually be modified to not escape.
n2 := 6 // OUT: object allocated on the heap: escapes at line 9
n2 := 6 // OUT: object allocated on the heap: escapes at line 11
returnIntPtr(&n2)

s1 := make([]int, 3)
Expand All @@ -15,36 +17,36 @@ func main() {
readIntSlice(s2[:])

// This should also be modified to not escape.
s3 := make([]int, 3) // OUT: object allocated on the heap: escapes at line 19
s3 := make([]int, 3) // OUT: object allocated on the heap: escapes at line 21
returnIntSlice(s3)

useSlice(make([]int, getUnknownNumber())) // OUT: object allocated on the heap: size is not constant

s4 := make([]byte, 300) // OUT: object allocated on the heap: object size 300 exceeds maximum stack allocation size 256
readByteSlice(s4)

s5 := make([]int, 4) // OUT: object allocated on the heap: escapes at line 27
s5 := make([]int, 4) // OUT: object allocated on the heap: escapes at line 29
_ = append(s5, 5)

s6 := make([]int, 3)
s7 := []int{1, 2, 3}
copySlice(s6, s7)

c1 := getComplex128() // OUT: object allocated on the heap: escapes at line 34
c1 := getComplex128() // OUT: object allocated on the heap: escapes at line 36
useInterface(c1)

n3 := 5
func() int {
return n3
}()

callVariadic(3, 5, 8) // OUT: object allocated on the heap: escapes at line 41
callVariadic(3, 5, 8) // OUT: object allocated on the heap: escapes at line 43

s8 := []int{3, 5, 8} // OUT: object allocated on the heap: escapes at line 44
s8 := []int{3, 5, 8} // OUT: object allocated on the heap: escapes at line 46
callVariadic(s8...)

n4 := 3 // OUT: object allocated on the heap: escapes at line 48
n5 := 7 // OUT: object allocated on the heap: escapes at line 48
n4 := 3 // OUT: object allocated on the heap: escapes at line 50
n5 := 7 // OUT: object allocated on the heap: escapes at line 50
func() {
n4 = n5
}()
Expand All @@ -58,6 +60,11 @@ func main() {
var rbuf [5]rune
s = string(rbuf[:])
println(s)

// This shouldn't escape either.
n6 := 3
n7 := uintptr(unsafe.Pointer(&n6))
println(n7)
}

func derefInt(x *int) int {
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