Add filetest for verifying emitted rodata (i.e. test rodata)

cranelift/filetests/src/test_rodata.rs

@@ -0,0 +1,123 @@
+//! Test command for verifying the rodata emitted after each function
+//!
+//! The `rodata` test command runs each function through the full code generator pipeline
+
+use crate::subtest::{run_filecheck, Context, SubTest, SubtestResult};
+use cranelift_codegen;
+use cranelift_codegen::binemit::{self, CodeInfo};
+use cranelift_codegen::ir;
+use cranelift_codegen::ir::{Function, Value};
+use cranelift_codegen::isa::TargetIsa;
+use cranelift_codegen::print_errors::pretty_error;
+use cranelift_reader::TestCommand;
+use log::info;
+use std::borrow::Cow;
+
+struct TestRodata;
+
+pub fn subtest(parsed: &TestCommand) -> SubtestResult<Box<dyn SubTest>> {
+    assert_eq!(parsed.command, "rodata");
+    if !parsed.options.is_empty() {
+        Err(format!("No options allowed on {}", parsed))
+    } else {
+        Ok(Box::new(TestRodata))
+    }
+}
+
+impl SubTest for TestRodata {
+    fn name(&self) -> &'static str {
+        "rodata"
+    }
+
+    fn is_mutating(&self) -> bool {
+        true
+    }
+
+    fn needs_isa(&self) -> bool {
+        true
+    }
+
+    fn run(&self, func: Cow<ir::Function>, context: &Context) -> SubtestResult<()> {
+        let isa = context.isa.expect("rodata needs an ISA");
+        let mut comp_ctx = cranelift_codegen::Context::for_function(func.into_owned());
+
+        let CodeInfo { total_size, .. } = comp_ctx
+            .compile(isa)
+            .map_err(|e| pretty_error(&comp_ctx.func, context.isa, e))?;
+
+        info!(
+            "Generated {} bytes of code:\n{}",
+            total_size,
+            comp_ctx.func.display(isa)
+        );
+
+        // Verify that the returned code size matches the emitted bytes.
+        let mut sink = RodataSink {
+            rodata: Vec::new(),
+            in_rodata: false,
+        };
+        binemit::emit_function(
+            &comp_ctx.func,
+            |func, inst, div, sink, isa| isa.emit_inst(func, inst, div, sink),
+            &mut sink,
+            isa,
+        );
+
+        // Run final code through filecheck.
+        let text = format!("{:X?}", sink.rodata);
+        info!("Found rodata: {}", text);
+        run_filecheck(&text, context)
+    }
+}
+
+/// Code sink that only captures emitted rodata
+struct RodataSink {
+    in_rodata: bool,
+    rodata: Vec<u8>,
+}
+
+impl binemit::CodeSink for RodataSink {
+    fn offset(&self) -> binemit::CodeOffset {
+        0
+    }
+
+    fn put1(&mut self, byte: u8) {
+        if self.in_rodata {
+            self.rodata.push(byte);
+        }
+    }
+
+    fn put2(&mut self, bytes: u16) {
+        if self.in_rodata {
+            self.rodata.extend_from_slice(&bytes.to_be_bytes());
+        }
+    }
+
+    fn put4(&mut self, bytes: u32) {
+        if self.in_rodata {
+            self.rodata.extend_from_slice(&bytes.to_be_bytes());
+        }
+    }
+
+    fn put8(&mut self, bytes: u64) {
+        if self.in_rodata {
+            self.rodata.extend_from_slice(&bytes.to_be_bytes());
+        }
+    }
+
+    fn reloc_ebb(&mut self, _reloc: binemit::Reloc, _ebb_offset: binemit::CodeOffset) {}
+    fn reloc_external(&mut self, _: binemit::Reloc, _: &ir::ExternalName, _: 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) {
+        assert!(!self.in_rodata);
+    }
+    fn begin_rodata(&mut self) {
+        self.in_rodata = true;
+    }
+    fn end_codegen(&mut self) {
+        assert!(self.in_rodata);
+    }
+    fn add_stackmap(&mut self, _: &[Value], _: &Function, _: &dyn TargetIsa) {}
+}