mirror of
https://github.com/tinygo-org/tinygo.git
synced 2026-08-02 01:57:48 +00:00
Ayke van Laethem
105 lines
3.5 KiB
Go
105 lines
3.5 KiB
Go
package compiler
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import (
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"math/big"
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"tinygo.org/x/go-llvm"
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)
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func (c *Compiler) addGlobalsBitmap() {
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if c.mod.NamedGlobal("runtime.trackedGlobalsStart").IsNil() {
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return // nothing to do: no GC in use
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}
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var trackedGlobals []llvm.Value
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var trackedGlobalTypes []llvm.Type
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for global := c.mod.FirstGlobal(); !global.IsNil(); global = llvm.NextGlobal(global) {
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if global.IsDeclaration() {
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continue
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}
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typ := global.Type().ElementType()
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ptrs := c.getPointerBitmap(typ, global.Name())
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if ptrs.BitLen() == 0 {
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continue
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}
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trackedGlobals = append(trackedGlobals, global)
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trackedGlobalTypes = append(trackedGlobalTypes, typ)
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}
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//
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globalsBundleType := c.ctx.StructType(trackedGlobalTypes, false)
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globalsBundle := llvm.AddGlobal(c.mod, globalsBundleType, "tinygo.trackedGlobals")
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globalsBundle.SetLinkage(llvm.InternalLinkage)
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globalsBundle.SetUnnamedAddr(true)
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initializer := llvm.Undef(globalsBundleType)
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for i, global := range trackedGlobals {
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initializer = llvm.ConstInsertValue(initializer, global.Initializer(), []uint32{uint32(i)})
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gep := llvm.ConstGEP(globalsBundle, []llvm.Value{
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llvm.ConstInt(c.ctx.Int32Type(), 0, false),
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llvm.ConstInt(c.ctx.Int32Type(), uint64(i), false),
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})
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global.ReplaceAllUsesWith(gep)
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global.EraseFromParentAsGlobal()
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}
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globalsBundle.SetInitializer(initializer)
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trackedGlobalsStart := llvm.ConstPtrToInt(globalsBundle, c.uintptrType)
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c.mod.NamedGlobal("runtime.trackedGlobalsStart").SetInitializer(trackedGlobalsStart)
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alignment := c.targetData.PrefTypeAlignment(c.i8ptrType)
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trackedGlobalsLength := llvm.ConstInt(c.uintptrType, c.targetData.TypeAllocSize(globalsBundleType)/uint64(alignment), false)
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c.mod.NamedGlobal("runtime.trackedGlobalsLength").SetInitializer(trackedGlobalsLength)
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bitmapBytes := c.getPointerBitmap(globalsBundleType, "globals bundle").Bytes()
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bitmapValues := make([]llvm.Value, len(bitmapBytes))
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for i, b := range bitmapBytes {
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bitmapValues[len(bitmapBytes)-i-1] = llvm.ConstInt(c.ctx.Int8Type(), uint64(b), false)
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}
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bitmapArray := llvm.ConstArray(llvm.ArrayType(c.ctx.Int8Type(), len(bitmapBytes)), bitmapValues)
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bitmapNew := llvm.AddGlobal(c.mod, bitmapArray.Type(), "runtime.trackedGlobalsBitmap.tmp")
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bitmapOld := c.mod.NamedGlobal("runtime.trackedGlobalsBitmap")
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bitmapOld.ReplaceAllUsesWith(bitmapNew)
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bitmapNew.SetInitializer(bitmapArray)
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bitmapNew.SetName("runtime.trackedGlobalsBitmap")
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}
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func (c *Compiler) getPointerBitmap(typ llvm.Type, name string) *big.Int {
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alignment := c.targetData.PrefTypeAlignment(c.i8ptrType)
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switch typ.TypeKind() {
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case llvm.IntegerTypeKind, llvm.FloatTypeKind, llvm.DoubleTypeKind:
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return big.NewInt(0)
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case llvm.PointerTypeKind:
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return big.NewInt(1)
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case llvm.StructTypeKind:
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ptrs := big.NewInt(0)
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for i, subtyp := range typ.StructElementTypes() {
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subptrs := c.getPointerBitmap(subtyp, name)
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if subptrs.BitLen() == 0 {
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continue
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}
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offset := c.targetData.ElementOffset(typ, i)
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if offset%uint64(alignment) != 0 {
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panic("precise GC: global contains unaligned pointer: " + name)
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}
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subptrs.Lsh(subptrs, uint(offset)/uint(alignment))
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ptrs.Or(ptrs, subptrs)
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}
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return ptrs
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case llvm.ArrayTypeKind:
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subtyp := typ.ElementType()
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subptrs := c.getPointerBitmap(subtyp, name)
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ptrs := big.NewInt(0)
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if subptrs.BitLen() == 0 {
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return ptrs
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}
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elementSize := c.targetData.TypeAllocSize(subtyp)
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for i := 0; i < typ.ArrayLength(); i++ {
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ptrs.Lsh(ptrs, uint(elementSize)/uint(alignment))
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ptrs.Or(ptrs, subptrs)
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}
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return ptrs
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default:
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panic("unknown type kind of global: " + name)
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}
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}
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