[solidity,llvm-context] Improve support for debugging the compiler (#32)

Add option --recursive-process-input <filename> for use with
--recursive-process to specify the name of a file to use instead of
reading from stdin.

If --debug-output-dir is set, dump the file passed to the recursive
invocation of the compiler as a JSON file suitable for use with
--recursive-process-input.

These changes are intended to support debugging the compiler and are
only available with DEBUG builds.

crates/llvm-context/src/debug_config/ir_type.rs

@@ -15,6 +15,9 @@ pub enum IRType {
     LLVM,
     /// Whether to dump the assembly code.
     Assembly,
+    /// Whether to jump JSON
+    #[cfg(debug_assertions)]
+    JSON,
 }
 
 impl IRType {
@@ -26,6 +29,8 @@ impl IRType {
             Self::EVMLA => revive_common::EXTENSION_EVMLA,
             Self::LLVM => revive_common::EXTENSION_LLVM_SOURCE,
             Self::Assembly => revive_common::EXTENSION_POLKAVM_ASSEMBLY,
+            #[cfg(debug_assertions)]
+            Self::JSON => revive_common::EXTENSION_JSON,
         }
     }
 }

crates/llvm-context/src/debug_config/mod.rs

@@ -94,6 +94,22 @@ impl DebugConfig {
         Ok(())
     }
 
+    /// Dumps the stage output as a json file suitable for use with --recursive-process
+    #[cfg(debug_assertions)]
+    pub fn dump_stage_output(
+        &self,
+        contract_path: &str,
+        contract_suffix: Option<&str>,
+        stage_json: &Vec<u8>,
+    ) -> anyhow::Result<()> {
+        let mut file_path = self.output_directory.to_owned();
+        let full_file_name = Self::full_file_name(contract_path, contract_suffix, IRType::JSON);
+        file_path.push(full_file_name);
+        std::fs::write(file_path, stage_json)?;
+
+        Ok(())
+    }
+
     /// Creates a full file name, given the contract full path, suffix, and extension.
     fn full_file_name(contract_path: &str, suffix: Option<&str>, ir_type: IRType) -> String {
         let mut full_file_name = contract_path.replace('/', "_").replace(':', ".");

crates/solidity/src/process/mod.rs

@@ -17,13 +17,27 @@ use self::output::Output;
 pub static EXECUTABLE: OnceCell<PathBuf> = OnceCell::new();
 
 /// Read input from `stdin`, compile a contract, and write the output to `stdout`.
-pub fn run() -> anyhow::Result<()> {
+pub fn run(input_file: Option<&mut std::fs::File>) -> anyhow::Result<()> {
     let mut stdin = std::io::stdin();
     let mut stdout = std::io::stdout();
     let mut stderr = std::io::stderr();
 
     let mut buffer = Vec::with_capacity(16384);
-    stdin.read_to_end(&mut buffer).expect("Stdin reading error");
+    match input_file {
+        Some(ins) => {
+            if let Err(error) = ins.read_to_end(&mut buffer) {
+                anyhow::bail!("Failed to read recursive process input file: {:?}", error);
+            }
+        }
+        None => {
+            if let Err(error) = stdin.read_to_end(&mut buffer) {
+                anyhow::bail!(
+                    "Failed to read recursive process input from stdin: {:?}",
+                    error
+                )
+            }
+        }
+    }
 
     let input: Input = revive_common::deserialize_from_slice(buffer.as_slice())?;
     if input.enable_test_encoding {
@@ -74,6 +88,19 @@ pub fn call(input: Input) -> anyhow::Result<Output> {
         anyhow::anyhow!("{:?} subprocess spawning error: {:?}", executable, error)
     })?;
 
+    #[cfg(debug_assertions)]
+    if let Some(dbg_config) = &input.debug_config {
+        let _ = dbg_config
+            .dump_stage_output(&input.contract.path, Some("stage"), &input_json)
+            .map_err(|error| {
+                anyhow::anyhow!(
+                    "{:?} failed to log the recursive process output: {:?}",
+                    executable,
+                    error,
+                )
+            })?;
+    }
+
     process
         .stdin
         .as_ref()

crates/solidity/src/resolc/arguments.rs

@@ -164,6 +164,12 @@ pub struct Arguments {
     /// Only for usage from within the compiler.
     #[structopt(long = "recursive-process")]
     pub recursive_process: bool,
+
+    /// Specify the input file to use instead of stdin when --recursive-process is given.
+    /// This is only intended for use when developing the compiler.
+    #[cfg(debug_assertions)]
+    #[structopt(long = "recursive-process-input")]
+    pub recursive_process_input: Option<String>,
 }
 
 impl Default for Arguments {
@@ -185,6 +191,20 @@ impl Arguments {
             anyhow::bail!("No other options are allowed while getting the compiler version.");
         }
 
+        #[cfg(debug_assertions)]
+        if self.recursive_process_input != None && !self.recursive_process {
+            anyhow::bail!("--process-input can be only used when --recursive-process is given");
+        }
+
+        #[cfg(debug_assertions)]
+        if self.recursive_process
+            && ((self.recursive_process_input == None && std::env::args().count() > 2)
+                || (self.recursive_process_input != None && std::env::args().count() > 4))
+        {
+            anyhow::bail!("No other options are allowed in recursive mode.");
+        }
+
+        #[cfg(not(debug_assertions))]
         if self.recursive_process && std::env::args().count() > 2 {
             anyhow::bail!("No other options are allowed in recursive mode.");
         }

crates/solidity/src/resolc/main.rs

@@ -47,7 +47,13 @@ fn main_inner() -> anyhow::Result<()> {
     revive_llvm_context::initialize_target(revive_llvm_context::Target::PVM); // TODO: pass from CLI
 
     if arguments.recursive_process {
-        return revive_solidity::run_process();
+        #[cfg(debug_assertions)]
+        if let Some(fname) = arguments.recursive_process_input {
+            let mut infile = std::fs::File::open(fname)?;
+            return revive_solidity::run_process(Some(&mut infile));
+        }
+
+        return revive_solidity::run_process(None);
     }
 
     let debug_config = match arguments.debug_output_directory {