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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.
// Most functions are defined but unimplemented to make sure that if there is
// any code using them, they will get an error instead of (incorrectly) using
// the wasi-libc dlmalloc heap implementation instead. If they are needed by any
// program, they can certainly be implemented.
//export malloc
func libc_malloc(size uintptr) unsafe.Pointer {
return alloc(size, nil)
}
//export free
func libc_free(ptr unsafe.Pointer) {
free(ptr)
}
//export calloc
func libc_calloc(nmemb, size uintptr) unsafe.Pointer {
// Note: we could be even more correct here and check that nmemb * size
// doesn't overflow. However the current implementation should normally work
// fine.
return alloc(nmemb*size, nil)
}
//export realloc
func libc_realloc(ptr unsafe.Pointer, size uintptr) unsafe.Pointer {
return realloc(ptr, size)
}
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