//! Test command for testing the code generator pipeline
//!
//! The `compile` test command runs each function through the full code generator pipeline

use crate::subtest::{run_filecheck, Context, SubTest};
use cranelift_codegen;
use cranelift_codegen::binemit::{self, CodeInfo};
use cranelift_codegen::ir;
use cranelift_codegen::isa;
use cranelift_reader::TestCommand;
use log::info;
use std::borrow::Cow;

struct TestCompile;

pub fn subtest(parsed: &TestCommand) -> anyhow::Result<Box<dyn SubTest>> {
    assert_eq!(parsed.command, "compile");
    if !parsed.options.is_empty() {
        anyhow::bail!("No options allowed on {}", parsed);
    }
    Ok(Box::new(TestCompile))
}

impl SubTest for TestCompile {
    fn name(&self) -> &'static str {
        "compile"
    }

    fn is_mutating(&self) -> bool {
        true
    }

    fn needs_isa(&self) -> bool {
        true
    }

    fn run(&self, func: Cow<ir::Function>, context: &Context) -> anyhow::Result<()> {
        let isa = context.isa.expect("compile needs an ISA");
        let mut comp_ctx = cranelift_codegen::Context::for_function(func.into_owned());

        if isa.get_mach_backend().is_some() {
            // With `MachBackend`s, we need to explicitly request dissassembly results.
            comp_ctx.set_disasm(true);
        }

        let CodeInfo { total_size, .. } = comp_ctx
            .compile(isa)
            .map_err(|e| crate::pretty_anyhow_error(&comp_ctx.func, context.isa, e))?;

        info!(
            "Generated {} bytes of code:\n{}",
            total_size,
            comp_ctx.func.display(isa)
        );

        if !isa.get_mach_backend().is_some() {
            // Verify that the returned code size matches the emitted bytes.
            let mut sink = SizeSink { offset: 0 };
            binemit::emit_function(
                &comp_ctx.func,
                |func, inst, div, sink, isa| isa.emit_inst(func, inst, div, sink),
                &mut sink,
                isa,
            );

            if sink.offset != total_size {
                anyhow::bail!("Expected code size {}, got {}", total_size, sink.offset);
            }

            // Run final code through filecheck.
            let text = comp_ctx.func.display(Some(isa)).to_string();
            run_filecheck(&text, context)
        } else {
            let disasm = comp_ctx
                .mach_compile_result
                .as_ref()
                .unwrap()
                .disasm
                .as_ref()
                .unwrap();
            run_filecheck(&disasm, context)
        }
    }
}

/// Code sink that simply counts bytes.
struct SizeSink {
    offset: binemit::CodeOffset,
}

impl binemit::CodeSink for SizeSink {
    fn offset(&self) -> binemit::CodeOffset {
        self.offset
    }

    fn put1(&mut self, _: u8) {
        self.offset += 1;
    }

    fn put2(&mut self, _: u16) {
        self.offset += 2;
    }

    fn put4(&mut self, _: u32) {
        self.offset += 4;
    }

    fn put8(&mut self, _: u64) {
        self.offset += 8;
    }

    fn reloc_external(
        &mut self,
        _srcloc: ir::SourceLoc,
        _reloc: binemit::Reloc,
        _name: &ir::ExternalName,
        _addend: binemit::Addend,
    ) {
    }
    fn reloc_constant(&mut self, _: binemit::Reloc, _: ir::ConstantOffset) {}
    fn reloc_jt(&mut self, _reloc: binemit::Reloc, _jt: ir::JumpTable) {}
    fn trap(&mut self, _code: ir::TrapCode, _srcloc: ir::SourceLoc) {}
    fn begin_jumptables(&mut self) {}
    fn begin_rodata(&mut self) {}
    fn end_codegen(&mut self) {}
    fn add_stack_map(
        &mut self,
        _: &[ir::entities::Value],
        _: &ir::Function,
        _: &dyn isa::TargetIsa,
    ) {
    }
}