Simplified compiler package

src/compiler/finalize.go

@@ -0,0 +1,74 @@
+package compiler
+
+import (
+	"git.akyoto.dev/cli/q/src/asm"
+	"git.akyoto.dev/cli/q/src/asmc"
+	"git.akyoto.dev/cli/q/src/config"
+	"git.akyoto.dev/cli/q/src/core"
+	"git.akyoto.dev/cli/q/src/dll"
+	"git.akyoto.dev/cli/q/src/x86"
+)
+
+// finalize generates the final machine code.
+func (r *Result) finalize() {
+	// This will be the entry point of the executable.
+	// The only job of the entry function is to call `main` and exit cleanly.
+	// The reason we call `main` instead of using `main` itself is to place
+	// a return address on the stack, which allows return statements in `main`.
+	final := asm.Assembler{
+		Instructions: make([]asm.Instruction, 0, r.InstructionCount+8),
+		Data:         make(map[string][]byte, r.DataCount),
+	}
+
+	final.Call("main.main")
+
+	switch config.TargetOS {
+	case config.Linux:
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[0], LinuxExit)
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[1], 0)
+		final.Syscall()
+	case config.Mac:
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[0], MacExit)
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[1], 0)
+		final.Syscall()
+	case config.Windows:
+		final.RegisterNumber(asm.MOVE, x86.WindowsInputRegisters[0], 0)
+		final.DLLCall("kernel32.ExitProcess")
+	}
+
+	r.DLLs = dll.List{
+		{Name: "kernel32", Functions: []string{"ExitProcess"}},
+	}
+
+	r.Traversed = make(map[*core.Function]bool, len(r.Functions))
+
+	// This will place the main function immediately after the entry point
+	// and also add everything the main function calls recursively.
+	r.eachFunction(r.Main, r.Traversed, func(f *core.Function) {
+		final.Merge(f.Assembler)
+
+		for _, library := range f.DLLs {
+			for _, fn := range library.Functions {
+				r.DLLs = r.DLLs.Append(library.Name, fn)
+			}
+		}
+	})
+
+	final.Label(asm.LABEL, "_crash")
+
+	switch config.TargetOS {
+	case config.Linux:
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[0], LinuxExit)
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[1], 1)
+		final.Syscall()
+	case config.Mac:
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[0], MacExit)
+		final.RegisterNumber(asm.MOVE, x86.SyscallInputRegisters[1], 1)
+		final.Syscall()
+	case config.Windows:
+		final.RegisterNumber(asm.MOVE, x86.WindowsInputRegisters[0], 1)
+		final.DLLCall("kernel32.ExitProcess")
+	}
+
+	r.Code, r.Data = asmc.Finalize(final, r.DLLs)
+}