From 8351ba3e3e69f840fbc1258e9effd43c8c59f036 Mon Sep 17 00:00:00 2001
From: Tyler McMullen <tbmcmullen@gmail.com>
Date: Mon, 23 Apr 2018 23:24:02 -0400
Subject: [PATCH] Disassemble compiled binary for debugging (#308)

* Use Capstone to disassemble and print code after compilation in cton-util.

* Fix rustfmt errors
---
 cranelift/Cargo.toml       |  1 +
 cranelift/src/compile.rs   | 41 +++++++++++++++++++++++++++++++++++++-
 cranelift/src/cton-util.rs |  1 +
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/cranelift/Cargo.toml b/cranelift/Cargo.toml
index ded5a8e588..dc916f116a 100644
--- a/cranelift/Cargo.toml
+++ b/cranelift/Cargo.toml
@@ -29,5 +29,6 @@ serde = "1.0.8"
 serde_derive = "1.0.8"
 tempdir = "0.3.5"
 term = "0.5.1"
+capstone = "0.3.1"
 
 [workspace]
diff --git a/cranelift/src/compile.rs b/cranelift/src/compile.rs
index 4b9f77494d..def23bf7de 100644
--- a/cranelift/src/compile.rs
+++ b/cranelift/src/compile.rs
@@ -1,8 +1,10 @@
 //! CLI tool to read Cretonne IR files and compile them into native code.
 
-use cretonne_codegen::Context;
+use capstone::prelude::*;
+use cretonne_codegen::isa::TargetIsa;
 use cretonne_codegen::print_errors::pretty_error;
 use cretonne_codegen::settings::FlagsOrIsa;
+use cretonne_codegen::Context;
 use cretonne_codegen::{binemit, ir};
 use cretonne_reader::parse_test;
 use std::path::Path;
@@ -121,8 +123,45 @@ fn handle_module(
                 print!("{}", byte);
             }
             println!();
+
+            let cs = get_disassembler(isa)?;
+
+            println!("\nDisassembly:");
+            let insns = cs.disasm_all(&mem, 0x0).unwrap();
+            for i in insns.iter() {
+                println!("{}", i);
+            }
         }
     }
 
     Ok(())
 }
+
+fn get_disassembler(isa: &TargetIsa) -> Result<Capstone, String> {
+    let cs = match isa.name() {
+        "riscv" => return Err(String::from("No disassembler for RiscV")),
+        "x86" => {
+            if isa.flags().is_64bit() {
+                Capstone::new()
+                    .x86()
+                    .mode(arch::x86::ArchMode::Mode64)
+                    .build()
+            } else {
+                Capstone::new()
+                    .x86()
+                    .mode(arch::x86::ArchMode::Mode32)
+                    .build()
+            }
+        }
+        "arm32" => Capstone::new().arm().mode(arch::arm::ArchMode::Arm).build(),
+        "arm64" => {
+            Capstone::new()
+                .arm64()
+                .mode(arch::arm64::ArchMode::Arm)
+                .build()
+        }
+        _ => return Err(String::from("Unknown ISA")),
+    };
+
+    cs.map_err(|err| err.to_string())
+}
diff --git a/cranelift/src/cton-util.rs b/cranelift/src/cton-util.rs
index d69c561c44..0010034a0a 100644
--- a/cranelift/src/cton-util.rs
+++ b/cranelift/src/cton-util.rs
@@ -20,6 +20,7 @@ extern crate filecheck;
 extern crate serde_derive;
 extern crate tempdir;
 extern crate term;
+extern crate capstone;
 
 use cretonne_codegen::{timing, VERSION};
 use docopt::Docopt;