WIP implement a machine readable print-type-info API

src/librustc/session/mod.rs

@@ -8,8 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-pub use self::code_stats::{CodeStats, DataTypeKind, FieldInfo};
-pub use self::code_stats::{SizeKind, TypeSizeInfo, VariantInfo};
+pub use self::print_type_info::{CodeStats};
+// pub use self::code_stats::{CodeStats, DataTypeKind, FieldInfo};
+// pub use self::code_stats::{SizeKind, TypeSizeInfo, VariantInfo};
 
 use dep_graph::DepGraph;
 use hir::def_id::{CrateNum, DefIndex};
@@ -51,7 +52,8 @@ use std::rc::Rc;
 use std::sync::{Once, ONCE_INIT};
 use std::time::Duration;
 
-mod code_stats;
+// mod code_stats;
+pub mod print_type_info;
 pub mod config;
 pub mod filesearch;
 pub mod search_paths;

src/librustc/session/print_type_info.rs

@@ -0,0 +1,154 @@
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+
+use rustc_data_structures::fx::FxHashSet;
+use std::mem;
+use std::hash::{Hash, Hasher};
+use std::collections::BTreeMap;
+use rustc_serialize::json::Json;
+
+pub struct CodeStats {
+    types: FxHashSet<Type>,
+}
+
+/// A Type name, with certain modifiers applied.
+///
+/// While a Type can have a name like rust::u32, a ComplexTypeName
+/// can include nested pointer/array modifiers:
+///
+/// * `*const ComplexTypeName`
+/// * `[ComplexTypeName; N]`
+///
+/// This avoids metadata blowup.
+///
+/// For example: `*const [*mut [rust::u32, 12], 32]`
+pub type ComplexTypeName = String;
+
+pub struct Type {
+    pub name: String,
+    pub size: u64,
+    pub align: u64,
+    pub public: bool,
+    pub kind: TypeKind,
+}
+
+pub enum TypeKind {
+    PrimitiveInt,
+    PrimitiveFloat,
+    Opaque,
+    Struct { fields: Vec<Field> },
+    Union { fields: Vec<Field> },
+    Enum { base_type: ComplexTypeName, cases: Vec<Case> },
+}
+
+pub struct Field {
+    pub name: String,
+    pub type_name: ComplexTypeName,
+    pub offset: u64,
+    pub public: bool,
+}
+
+pub struct Case {
+    pub name: String,
+    pub value: i64, // TODO: u64/u128/i128? (serialize doesn't support)
+}
+
+impl PartialEq for Type {
+    fn eq(&self, other: &Self) -> bool { self.name == other.name }
+}
+impl Eq for Type {}
+impl Hash for Type {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.name.hash(state);
+    }
+}
+
+
+impl TypeKind {
+    fn as_str(&self) -> &'static str {
+        match *self {
+            TypeKind::PrimitiveInt => "primitive_int",
+            TypeKind::PrimitiveFloat => "primitive_float",
+            TypeKind::Opaque => "opaque",
+            TypeKind::Struct { .. } => "struct",
+            TypeKind::Union { .. } => "union",
+            TypeKind::Enum { .. } => "enum",
+        }
+    }
+}
+
+impl CodeStats {
+    pub fn new() -> Self {
+        CodeStats { types: FxHashSet::default() }
+    }
+
+    pub fn insert(&mut self, ty: Type) {
+        self.types.insert(ty);
+    }
+
+    pub fn print_type_sizes(&mut self) {
+        let types = mem::replace(&mut self.types, FxHashSet::default());
+
+        let mut output = Vec::with_capacity(types.len());
+
+        for ty in types {
+            let mut json = BTreeMap::new();
+
+            json.insert("name".to_string(), Json::String(ty.name));
+            json.insert("size".to_string(), Json::U64(ty.size));
+            json.insert("align".to_string(), Json::U64(ty.align));
+            json.insert("public".to_string(), Json::Boolean(ty.public));
+            json.insert("kind".to_string(), Json::String(ty.kind.as_str().to_string()));
+
+            match ty.kind {
+                TypeKind::Struct { fields } | TypeKind::Union { fields } => {
+                    let fields_json = fields.into_iter().map(field_to_json).collect();
+                    json.insert("fields".to_string(), Json::Array(fields_json));
+                }
+                TypeKind::Enum { base_type, cases } => {
+                    json.insert("base_type".to_string(), Json::String(base_type));
+                    let cases_json = cases.into_iter().map(case_to_json).collect();
+                    json.insert("cases".to_string(), Json::Array(cases_json));
+                }
+                _ => { /* nothing */ }
+            }
+
+            output.push(Json::Object(json));
+        }
+
+        println!("WARNING: these values are platform-specific, implementation-specific, \
+            and compilation-specific. They can and will change for absolutely no reason. \
+            To use this properly, you must recompute and evaluate them on each compilation \
+            of your crate. Yes we broke your JSON parsing just to say this. We're not \
+            kidding here.");
+        println!("{}", Json::Array(output));
+    }
+}
+
+fn case_to_json(case: Case) -> Json {
+    let mut json = BTreeMap::new();
+
+    json.insert("name".to_string(), Json::String(case.name));
+    json.insert("value".to_string(), Json::I64(case.value));
+
+    Json::Object(json)
+}
+
+fn field_to_json(field: Field) -> Json {
+    let mut json = BTreeMap::new();
+
+    json.insert("name".to_string(), Json::String(field.name));
+    json.insert("type".to_string(), Json::String(field.type_name));
+    json.insert("offset".to_string(), Json::U64(field.offset));
+    json.insert("public".to_string(), Json::Boolean(field.public));
+
+    Json::Object(json)
+}