Change CLI argument to --derive

c2rust-transpile/src/lib.rs

@@ -25,6 +25,7 @@ use itertools::Itertools;
 use log::{info, warn};
 use regex::Regex;
 use serde_derive::Serialize;
+use strum_macros::Display;
 
 use crate::c_ast::Printer;
 use crate::c_ast::*;
@@ -82,7 +83,7 @@ pub struct TranspilerConfig {
     pub disable_refactoring: bool,
     pub preserve_unused_functions: bool,
     pub log_level: log::LevelFilter,
-    pub derive_debug: bool,
+    pub derives: HashSet<Derive>,
 
     // Options that control build files
     /// Emit `Cargo.toml` and `lib.rs`
@@ -92,6 +93,14 @@ pub struct TranspilerConfig {
     pub binaries: Vec<String>,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash, Display)]
+pub enum Derive {
+    Clone,
+    Copy,
+    Debug,
+    BitfieldStruct,
+}
+
 impl TranspilerConfig {
     fn binary_name_from_path(file: &Path) -> String {
         let file = Path::new(file.file_stem().unwrap());

c2rust-transpile/src/translator/mod.rs

@@ -11,6 +11,7 @@ use dtoa;
 use failure::{err_msg, format_err, Fail};
 use indexmap::indexmap;
 use indexmap::{IndexMap, IndexSet};
+use itertools::Itertools;
 use log::{error, info, trace, warn};
 use proc_macro2::{Punct, Spacing::*, Span, TokenStream, TokenTree};
 use syn::spanned::Spanned as _;
@@ -27,12 +28,12 @@ use c2rust_ast_builder::{mk, properties::*, Builder};
 use c2rust_ast_printer::pprust::{self};
 
 use crate::c_ast::iterators::{DFExpr, SomeId};
-use crate::c_ast::*;
 use crate::cfg;
 use crate::convert_type::TypeConverter;
 use crate::renamer::Renamer;
 use crate::with_stmts::WithStmts;
 use crate::{c_ast, format_translation_err};
+use crate::{c_ast::*, Derive};
 use crate::{ExternCrate, ExternCrateDetails, TranspilerConfig};
 use c2rust_ast_exporter::clang_ast::LRValue;
 
@@ -1640,14 +1641,6 @@ impl<'c> Translation<'c> {
                     can_derive_debug,
                 } = self.convert_struct_fields(decl_id, fields, platform_byte_size)?;
 
-                let mut derives = vec![];
-                if !contains_va_list {
-                    derives.push("Copy");
-                    derives.push("Clone");
-                };
-                if self.tcfg.derive_debug && can_derive_debug {
-                    derives.push("Debug");
-                }
                 let has_bitfields =
                     fields
                         .iter()
@@ -1656,10 +1649,27 @@ impl<'c> Translation<'c> {
                             _ => unreachable!("Found non-field in record field list"),
                         });
                 if has_bitfields {
-                    derives.push("BitfieldStruct");
                     self.use_crate(ExternCrate::C2RustBitfields);
                 }
 
+                let derives = self
+                    .tcfg
+                    .derives
+                    .iter()
+                    .flat_map(|derive| {
+                        let can_derive = match derive {
+                            Derive::Clone | Derive::Copy => !contains_va_list,
+                            Derive::Debug => can_derive_debug,
+                            Derive::BitfieldStruct => has_bitfields,
+                        };
+                        if can_derive {
+                            Some(derive.to_string())
+                        } else {
+                            None
+                        }
+                    })
+                    .collect_vec();
+
                 let mut reprs = vec![simple_metaitem("C")];
                 let max_field_alignment = if is_packed {
                     // `__attribute__((packed))` forces a max alignment of 1,
@@ -1710,10 +1720,22 @@ impl<'c> Translation<'c> {
                     let repr_attr = mk().meta_list("repr", outer_reprs);
                     let outer_field = mk().pub_().enum_field(mk().ident_ty(inner_name));
 
-                    let mut outer_struct_derives = vec!["Copy", "Clone"];
-                    if self.tcfg.derive_debug {
-                        outer_struct_derives.push("Debug");
-                    }
+                    let outer_struct_derives = self
+                        .tcfg
+                        .derives
+                        .iter()
+                        .flat_map(|derive| {
+                            let can_derive = match derive {
+                                Derive::Clone | Derive::Copy | Derive::Debug => true,
+                                Derive::BitfieldStruct => false,
+                            };
+                            if can_derive {
+                                Some(derive.to_string())
+                            } else {
+                                None
+                            }
+                        })
+                        .collect_vec();
 
                     let outer_struct = mk()
                         .span(span)

c2rust/src/bin/c2rust-transpile.rs

@@ -3,7 +3,9 @@ use log::LevelFilter;
 use regex::Regex;
 use std::{fs, path::PathBuf};
 
-use c2rust_transpile::{Diagnostic, ReplaceMode, TranspilerConfig};
+use c2rust_transpile::{Derive, Diagnostic, ReplaceMode, TranspilerConfig};
+
+const DEFAULT_DERIVES: &[Derive] = &[Derive::Clone, Derive::Copy, Derive::BitfieldStruct];
 
 #[derive(Debug, Parser)]
 #[clap(
@@ -156,9 +158,16 @@ struct Args {
     #[clap(long)]
     fail_on_multiple: bool,
 
-    /// Derive `Debug` trait for any structs that allow it (i.e., do not recursively contain any unions)
-    #[clap(long)]
-    derive_debug: bool,
+    /// Add extra derived traits to generated structs in addition to the default
+    /// set of derives (Copy, Clone, BitfieldStruct). Specify multiple times to
+    /// add more than one derive. A struct will derive all traits in the set for
+    /// which it is eligible.
+    ///
+    /// For example, a struct containing a union cannot derive Debug, so
+    /// `#[derive(Debug)]` will not be added to that struct regardless of
+    /// whether `--derive Debug` is specified.
+    #[clap(long = "derive", value_enum, value_name = "TRAIT")]
+    extra_derives: Vec<ExtraDerive>,
 }
 
 #[derive(Debug, PartialEq, Eq, ValueEnum, Clone)]
@@ -168,9 +177,29 @@ enum InvalidCodes {
     CompileError,
 }
 
+#[derive(Clone, Copy, Debug, ValueEnum)]
+#[clap(rename_all = "PascalCase")]
+enum ExtraDerive {
+    Debug,
+}
+
+impl ExtraDerive {
+    fn to_transpiler_derive(&self) -> Derive {
+        match self {
+            Self::Debug => Derive::Debug,
+        }
+    }
+}
+
 fn main() {
     let args = Args::parse();
 
+    let derives = DEFAULT_DERIVES
+        .iter()
+        .cloned()
+        .chain(args.extra_derives.iter().map(|d| d.to_transpiler_derive()))
+        .collect();
+
     // Build a TranspilerConfig from the command line
     let mut tcfg = TranspilerConfig {
         dump_untyped_context: args.dump_untyped_clang_ast,
@@ -220,7 +249,7 @@ fn main() {
         emit_no_std: args.emit_no_std,
         enabled_warnings: args.warn.into_iter().collect(),
         log_level: args.log_level,
-        derive_debug: args.derive_debug,
+        derives,
     };
     // binaries imply emit-build-files
     if !tcfg.binaries.is_empty() {

scripts/test_translator.py

@@ -72,7 +72,12 @@ def __init__(self, log_level: str, path: str, flags: Set[str] = set()) -> None:
         self.translate_const_macros = "translate_const_macros" in flags
         self.reorganize_definitions = "reorganize_definitions" in flags
         self.emit_build_files = "emit_build_files" in flags
-        self.derive_debug = "derive_debug" in flags
+
+        derive_flag_prefix = "derive:"
+        derives = set()
+        for derive_flag in filter(lambda f: f.startswith(derive_flag_prefix), flags):
+            derives.add(derive_flag.removeprefix(derive_flag_prefix))
+        self.derives = derives
 
     def translate(self, cc_db: str, ld_lib_path: str, extra_args: List[str] = []) -> RustFile:
         extensionless_file, _ = os.path.splitext(self.path)
@@ -97,8 +102,9 @@ def translate(self, cc_db: str, ld_lib_path: str, extra_args: List[str] = []) ->
             args.append("--reorganize-definitions")
         if self.emit_build_files:
             args.append("--emit-build-files")
-        if self.derive_debug:
-            args.append("--derive-debug")
+
+        for derive in self.derives:
+            args.extend(["--derive", derive])
 
         if self.log_level == 'DEBUG':
             args.append("--log-level=debug")

tests/structs/src/debug_derive_bad.c

@@ -1,4 +1,4 @@
-//! derive_debug
+//! derive:Debug
 
 // A struct containing a union is not debuggable
 typedef struct {

tests/structs/src/debug_derive_good.c

@@ -1,4 +1,4 @@
-//! derive_debug
+//! derive:Debug
 
 #include <stdarg.h>