q/src/build/core/CompileCall.go
2024-07-30 20:02:55 +02:00

90 lines
1.8 KiB
Go

package core
import (
"fmt"
"git.akyoto.dev/cli/q/src/build/asm"
"git.akyoto.dev/cli/q/src/build/errors"
"git.akyoto.dev/cli/q/src/build/expression"
)
// CompileCall executes a function call.
// All call registers must hold the correct parameter values before the function invocation.
// Registers that are in use must be saved if they are modified by the function.
// After the function call, they must be restored in reverse order.
func (f *Function) CompileCall(root *expression.Expression) error {
var (
pkg = f.Package
nameRoot = root.Children[0]
name string
fullName string
)
if nameRoot.IsLeaf() {
name = nameRoot.Token.Text(f.File.Bytes)
} else {
pkg = nameRoot.Children[0].Token.Text(f.File.Bytes)
name = nameRoot.Children[1].Token.Text(f.File.Bytes)
}
isSyscall := name == "syscall"
if !isSyscall {
fullName = fmt.Sprintf("%s.%s", pkg, name)
_, exists := f.Functions[fullName]
if !exists {
return errors.New(&errors.UnknownFunction{Name: name}, f.File, root.Children[0].Token.Position)
}
}
parameters := root.Children[1:]
registers := f.CPU.Input[:len(parameters)]
if isSyscall {
registers = f.CPU.Syscall[:len(parameters)]
}
err := f.ExpressionsToRegisters(parameters, registers)
if err != nil {
return err
}
f.SaveRegister(f.CPU.Output[0])
// Push
for _, register := range f.CPU.General {
if f.RegisterIsUsed(register) {
f.Register(asm.PUSH, register)
}
}
// Call
if isSyscall {
f.Syscall()
} else {
f.Call(fullName)
}
// Free parameter registers
for _, register := range registers {
if register == f.CPU.Output[0] && root.Parent != nil {
continue
}
f.FreeRegister(register)
}
// Pop
for i := len(f.CPU.General) - 1; i >= 0; i-- {
register := f.CPU.General[i]
if f.RegisterIsUsed(register) {
f.Register(asm.POP, register)
}
}
return nil
}