96 lines
2.2 KiB
Go
96 lines
2.2 KiB
Go
package expr
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import "llvm.org/llvm/bindings/go/llvm"
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type BuildCtx struct {
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C *Ctx
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B llvm.Builder
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M llvm.Module
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}
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func (bctx BuildCtx) Build(stmts ...Statement) llvm.Value {
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var lastVal llvm.Value
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for _, stmt := range stmts {
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if e := bctx.BuildStmt(stmt); e != nil {
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lastVal = bctx.buildVal(e)
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}
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}
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if (lastVal == llvm.Value{}) {
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lastVal = bctx.B.CreateRetVoid()
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}
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return lastVal
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}
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func (bctx BuildCtx) BuildStmt(s Statement) Expr {
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m := s.Op.(Macro)
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fn := bctx.C.GetMacro(m)
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if fn == nil {
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panicf("unknown macro: %q", m)
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}
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return fn(bctx, s.Arg)
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}
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// may return nil if e is a Statement which has no return
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func (bctx BuildCtx) buildExpr(e Expr) Expr {
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return bctx.buildExprTill(e, func(Expr) bool { return false })
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}
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// like buildExpr, but will stop short and stop recursing when the function
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// returns true
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func (bctx BuildCtx) buildExprTill(e Expr, fn func(e Expr) bool) Expr {
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if fn(e) {
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return e
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}
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switch ea := e.(type) {
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case llvmVal:
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return e
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case Int:
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return llvmVal(llvm.ConstInt(llvm.Int64Type(), uint64(ea), false))
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case Identifier:
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if ev := bctx.C.GetIdentifier(ea); ev != nil {
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return ev
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}
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panicf("identifier %q not found", ea)
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case Statement:
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return bctx.BuildStmt(ea)
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case Tuple:
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for i := range ea {
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ea[i] = bctx.buildExprTill(ea[i], fn)
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}
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return ea
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default:
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panicf("type %T can't express a value", ea)
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}
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panic("go is dumb")
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}
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func (bctx BuildCtx) buildVal(e Expr) llvm.Value {
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return llvm.Value(bctx.buildExpr(e).(llvmVal))
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}
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// globalCtx describes what's available to *all* contexts, and is what all
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// contexts should have as the root parent in the tree
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var globalCtx = &Ctx{
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macros: map[Macro]MacroFn{
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"add": func(bctx BuildCtx, e Expr) Expr {
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tup := bctx.buildExpr(e).(Tuple)
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a := bctx.buildVal(tup[0])
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b := bctx.buildVal(tup[1])
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return llvmVal(bctx.B.CreateAdd(a, b, ""))
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},
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"bind": func(bctx BuildCtx, e Expr) Expr {
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tup := bctx.buildExprTill(e, isIdentifier).(Tuple)
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id := bctx.buildExprTill(tup[0], isIdentifier).(Identifier)
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if bctx.C.idents[id] != nil {
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panicf("identifier %q is already bound", id)
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}
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bctx.C.idents[id] = bctx.buildExpr(tup[1])
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return nil
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},
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},
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}
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