Golang ssa.CallInstruction类代码示例

// genCall generates constraints for call instruction instr.
func (a *analysis) genCall(caller *cgnode, instr ssa.CallInstruction) {
	call := instr.Common()

	// Intrinsic implementations of built-in functions.
	if _, ok := call.Value.(*ssa.Builtin); ok {
		a.genBuiltinCall(instr, caller)
		return
	}

	var result nodeid
	if v := instr.Value(); v != nil {
		result = a.valueNode(v)
	}

	site := &callsite{instr: instr}
	if call.StaticCallee() != nil {
		a.genStaticCall(caller, site, call, result)
	} else if call.IsInvoke() {
		a.genInvoke(caller, site, call, result)
	} else {
		a.genDynamicCall(caller, site, call, result)
	}

	caller.sites = append(caller.sites, site)

	if a.log != nil {
		// TODO(adonovan): debug: improve log message.
		fmt.Fprintf(a.log, "\t%s to targets %s from %s\n", site, site.targets, caller)
	}
}

// addEdge adds the specified call graph edge, and marks it reachable.
// addrTaken indicates whether to mark the callee as "address-taken".
func (r *rta) addEdge(site ssa.CallInstruction, callee *ssa.Function, addrTaken bool) {
	r.addReachable(callee, addrTaken)

	if g := r.result.CallGraph; g != nil {
		if site.Parent() == nil {
			panic(site)
		}
		from := g.CreateNode(site.Parent())
		to := g.CreateNode(callee)
		callgraph.AddEdge(from, site, to)
	}
}

// visitInvoke is called each time the algorithm encounters an "invoke"-mode call.
func (r *rta) visitInvoke(site ssa.CallInstruction) {
	I := site.Common().Value.Type().Underlying().(*types.Interface)

	// Record the invoke site.
	sites, _ := r.invokeSites.At(I).([]ssa.CallInstruction)
	r.invokeSites.Set(I, append(sites, site))

	// Add callgraph edge for each existing
	// address-taken concrete type implementing I.
	for _, C := range r.implementations(I) {
		r.addInvokeEdge(site, C)
	}
}

// visitDynCall is called each time we encounter a dynamic "call"-mode call.
func (r *rta) visitDynCall(site ssa.CallInstruction) {
	S := site.Common().Signature()

	// Record the call site.
	sites, _ := r.dynCallSites.At(S).([]ssa.CallInstruction)
	r.dynCallSites.Set(S, append(sites, site))

	// For each function of signature S that we know is address-taken,
	// mark it reachable.  We'll add the callgraph edges later.
	funcs, _ := r.addrTakenFuncsBySig.At(S).(map[*ssa.Function]bool)
	for g := range funcs {
		r.addEdge(site, g, true)
	}
}

// callInstruction translates function call instructions.
func (fr *frame) callInstruction(instr ssa.CallInstruction) []*govalue {
	call := instr.Common()
	if builtin, ok := call.Value.(*ssa.Builtin); ok {
		var typ types.Type
		if v := instr.Value(); v != nil {
			typ = v.Type()
		}
		return fr.callBuiltin(typ, builtin, call.Args)
	}

	args := make([]*govalue, len(call.Args))
	for i, arg := range call.Args {
		args[i] = fr.value(arg)
	}

	var fn *govalue
	var chain llvm.Value
	if call.IsInvoke() {
		var recv *govalue
		fn, recv = fr.interfaceMethod(fr.llvmvalue(call.Value), call.Value.Type(), call.Method)
		args = append([]*govalue{recv}, args...)
	} else {
		if ssafn, ok := call.Value.(*ssa.Function); ok {
			llfn := fr.resolveFunctionGlobal(ssafn)
			llfn = llvm.ConstBitCast(llfn, llvm.PointerType(llvm.Int8Type(), 0))
			fn = newValue(llfn, ssafn.Type())
		} else {
			// First-class function values are stored as *{*fnptr}, so
			// we must extract the function pointer. We must also
			// set the chain, in case the function is a closure.
			fn = fr.value(call.Value)
			chain = fn.value
			fnptr := fr.builder.CreateBitCast(fn.value, llvm.PointerType(fn.value.Type(), 0), "")
			fnptr = fr.builder.CreateLoad(fnptr, "")
			fn = newValue(fnptr, fn.Type())
		}
		if recv := call.Signature().Recv(); recv != nil {
			if _, ok := recv.Type().Underlying().(*types.Pointer); !ok {
				recvalloca := fr.allocaBuilder.CreateAlloca(args[0].value.Type(), "")
				fr.builder.CreateStore(args[0].value, recvalloca)
				args[0] = newValue(recvalloca, types.NewPointer(args[0].Type()))
			}
		}
	}
	return fr.createCall(fn, chain, args)
}

// genBuiltinCall generates contraints for a call to a built-in.
func (a *analysis) genBuiltinCall(instr ssa.CallInstruction, cgn *cgnode) {
	call := instr.Common()
	switch call.Value.(*ssa.Builtin).Name() {
	case "append":
		// Safe cast: append cannot appear in a go or defer statement.
		a.genAppend(instr.(*ssa.Call), cgn)

	case "copy":
		tElem := call.Args[0].Type().Underlying().(*types.Slice).Elem()
		a.copyElems(cgn, tElem, call.Args[0], call.Args[1])

	case "panic":
		a.copy(a.panicNode, a.valueNode(call.Args[0]), 1)

	case "recover":
		if v := instr.Value(); v != nil {
			a.copy(a.valueNode(v), a.panicNode, 1)
		}

	case "print":
		// In the tests, the probe might be the sole reference
		// to its arg, so make sure we create nodes for it.
		if len(call.Args) > 0 {
			a.valueNode(call.Args[0])
		}

	case "ssa:wrapnilchk":
		a.copy(a.valueNode(instr.Value()), a.valueNode(call.Args[0]), 1)

	default:
		// No-ops: close len cap real imag complex print println delete.
	}
}

// createThunk creates a thunk from a
// given function and arguments, suitable for use with
// "defer" and "go".
func (fr *frame) createThunk(call ssa.CallInstruction) (thunk llvm.Value, arg llvm.Value) {
	seenarg := make(map[ssa.Value]bool)
	var args []ssa.Value
	var argtypes []*types.Var

	packArg := func(arg ssa.Value) {
		switch arg.(type) {
		case *ssa.Builtin, *ssa.Function, *ssa.Const, *ssa.Global:
			// Do nothing: we can generate these in the thunk
		default:
			if !seenarg[arg] {
				seenarg[arg] = true
				args = append(args, arg)
				field := types.NewField(0, nil, "_", arg.Type(), true)
				argtypes = append(argtypes, field)
			}
		}
	}

	packArg(call.Common().Value)
	for _, arg := range call.Common().Args {
		packArg(arg)
	}

	var isRecoverCall bool
	i8ptr := llvm.PointerType(llvm.Int8Type(), 0)
	var structllptr llvm.Type
	if len(args) == 0 {
		if builtin, ok := call.Common().Value.(*ssa.Builtin); ok {
			isRecoverCall = builtin.Name() == "recover"
		}
		if isRecoverCall {
			// When creating a thunk for recover(), we must pass fr.canRecover.
			arg = fr.builder.CreateZExt(fr.canRecover, fr.target.IntPtrType(), "")
			arg = fr.builder.CreateIntToPtr(arg, i8ptr, "")
		} else {
			arg = llvm.ConstPointerNull(i8ptr)
		}
	} else {
		structtype := types.NewStruct(argtypes, nil)
		arg = fr.createTypeMalloc(structtype)
		structllptr = arg.Type()
		for i, ssaarg := range args {
			argptr := fr.builder.CreateStructGEP(arg, i, "")
			fr.builder.CreateStore(fr.llvmvalue(ssaarg), argptr)
		}
		arg = fr.builder.CreateBitCast(arg, i8ptr, "")
	}

	thunkfntype := llvm.FunctionType(llvm.VoidType(), []llvm.Type{i8ptr}, false)
	thunkfn := llvm.AddFunction(fr.module.Module, "", thunkfntype)
	thunkfn.SetLinkage(llvm.InternalLinkage)
	fr.addCommonFunctionAttrs(thunkfn)

	thunkfr := newFrame(fr.unit, thunkfn)
	defer thunkfr.dispose()

	prologuebb := llvm.AddBasicBlock(thunkfn, "prologue")
	thunkfr.builder.SetInsertPointAtEnd(prologuebb)

	if isRecoverCall {
		thunkarg := thunkfn.Param(0)
		thunkarg = thunkfr.builder.CreatePtrToInt(thunkarg, fr.target.IntPtrType(), "")
		thunkfr.canRecover = thunkfr.builder.CreateTrunc(thunkarg, llvm.Int1Type(), "")
	} else if len(args) > 0 {
		thunkarg := thunkfn.Param(0)
		thunkarg = thunkfr.builder.CreateBitCast(thunkarg, structllptr, "")
		for i, ssaarg := range args {
			thunkargptr := thunkfr.builder.CreateStructGEP(thunkarg, i, "")
			thunkarg := thunkfr.builder.CreateLoad(thunkargptr, "")
			thunkfr.env[ssaarg] = newValue(thunkarg, ssaarg.Type())
		}
	}

	_, isDefer := call.(*ssa.Defer)

	entrybb := llvm.AddBasicBlock(thunkfn, "entry")
	br := thunkfr.builder.CreateBr(entrybb)
	thunkfr.allocaBuilder.SetInsertPointBefore(br)

	thunkfr.builder.SetInsertPointAtEnd(entrybb)
	var exitbb llvm.BasicBlock
	if isDefer {
		exitbb = llvm.AddBasicBlock(thunkfn, "exit")
		thunkfr.runtime.setDeferRetaddr.call(thunkfr, llvm.BlockAddress(thunkfn, exitbb))
	}
	if isDefer && isRecoverCall {
		thunkfr.callRecover(true)
	} else {
		thunkfr.callInstruction(call)
	}
	if isDefer {
		thunkfr.builder.CreateBr(exitbb)
		thunkfr.builder.SetInsertPointAtEnd(exitbb)
	}
	thunkfr.builder.CreateRetVoid()

//.........这里部分代码省略.........

// addInvokeEdge is called for each new pair (site, C) in the matrix.
func (r *rta) addInvokeEdge(site ssa.CallInstruction, C types.Type) {
	// Ascertain the concrete method of C to be called.
	imethod := site.Common().Method
	cmethod := r.prog.Method(r.prog.MethodSets.MethodSet(C).Lookup(imethod.Pkg(), imethod.Name()))
	r.addEdge(site, cmethod, true)
}