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//go:build tinygo.wasm
// +build tinygo.wasm
package runtime
import (
"unsafe"
)
const GOARCH = "wasm"
// The bitness of the CPU (e.g. 8, 32, 64).
const TargetBits = 32
const deferExtraRegs = 0
//go:extern __heap_base
var heapStartSymbol [0]byte
//go:extern __global_base
var globalsStartSymbol [0]byte
//export llvm.wasm.memory.size.i32
func wasm_memory_size(index int32) int32
//export llvm.wasm.memory.grow.i32
func wasm_memory_grow(index int32, delta int32) int32
var (
heapStart = uintptr(unsafe.Pointer(&heapStartSymbol))
heapEnd = uintptr(wasm_memory_size(0) * wasmPageSize)
globalsStart = uintptr(unsafe.Pointer(&globalsStartSymbol))
globalsEnd = uintptr(unsafe.Pointer(&heapStartSymbol))
)
const wasmPageSize = 64 * 1024
func align(ptr uintptr) uintptr {
// Align to 16, which is the alignment of max_align_t:
// https://godbolt.org/z/dYqTsWrGq
const heapAlign = 16
return (ptr + heapAlign - 1) &^ (heapAlign - 1)
}
func getCurrentStackPointer() uintptr
// growHeap tries to grow the heap size. It returns true if it succeeds, false
// otherwise.
func growHeap() bool {
// Grow memory by the available size, which means the heap size is doubled.
memorySize := wasm_memory_size(0)
result := wasm_memory_grow(0, memorySize)
if result == -1 {
// Grow failed.
return false
}
setHeapEnd(uintptr(wasm_memory_size(0) * wasmPageSize))
// Heap has grown successfully.
return true
}
// The below functions override the default allocator of wasi-libc. This ensures
// code linked from other languages can allocate memory without colliding with
// our GC allocations.
var allocs = make(map[uintptr][]byte)
//export malloc
func libc_malloc(size uintptr) unsafe.Pointer {
buf := make([]byte, size)
ptr := unsafe.Pointer(&buf[0])
allocs[uintptr(ptr)] = buf
return ptr
}
//export free
func libc_free(ptr unsafe.Pointer) {
if ptr == nil {
return
}
if _, ok := allocs[uintptr(ptr)]; ok {
delete(allocs, uintptr(ptr))
} else {
panic("free: invalid pointer")
}
}
//export calloc
func libc_calloc(nmemb, size uintptr) unsafe.Pointer {
// No difference between calloc and malloc.
return libc_malloc(nmemb * size)
}
//export realloc
func libc_realloc(oldPtr unsafe.Pointer, size uintptr) unsafe.Pointer {
// It's hard to optimize this to expand the current buffer with our GC, but
// it is theoretically possible. For now, just always allocate fresh.
buf := make([]byte, size)
if oldPtr != nil {
if oldBuf, ok := allocs[uintptr(oldPtr)]; ok {
copy(buf, oldBuf)
delete(allocs, uintptr(oldPtr))
} else {
panic("realloc: invalid pointer")
}
}
ptr := unsafe.Pointer(&buf[0])
allocs[uintptr(ptr)] = buf
return ptr
}
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