454 lines
17 KiB
Rust
454 lines
17 KiB
Rust
// Copyright 2012-2014 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.
|
|
|
|
//! Calculation of a Strict Version Hash for crates. For a length
|
|
//! comment explaining the general idea, see `librustc/middle/svh.rs`.
|
|
|
|
use std::hash::{Hash, SipHasher, Hasher};
|
|
use rustc::hir::def_id::{CRATE_DEF_INDEX, DefId};
|
|
use rustc::hir::svh::Svh;
|
|
use rustc::ty::TyCtxt;
|
|
use rustc::hir::intravisit::{self, Visitor};
|
|
|
|
use self::svh_visitor::StrictVersionHashVisitor;
|
|
|
|
pub trait SvhCalculate {
|
|
/// Calculate the SVH for an entire krate.
|
|
fn calculate_krate_hash(self) -> Svh;
|
|
|
|
/// Calculate the SVH for a particular item.
|
|
fn calculate_item_hash(self, def_id: DefId) -> u64;
|
|
}
|
|
|
|
impl<'a, 'tcx> SvhCalculate for TyCtxt<'a, 'tcx, 'tcx> {
|
|
fn calculate_krate_hash(self) -> Svh {
|
|
// FIXME (#14132): This is better than it used to be, but it still not
|
|
// ideal. We now attempt to hash only the relevant portions of the
|
|
// Crate AST as well as the top-level crate attributes. (However,
|
|
// the hashing of the crate attributes should be double-checked
|
|
// to ensure it is not incorporating implementation artifacts into
|
|
// the hash that are not otherwise visible.)
|
|
|
|
let crate_disambiguator = self.sess.local_crate_disambiguator();
|
|
let krate = self.map.krate();
|
|
|
|
// FIXME: this should use SHA1, not SipHash. SipHash is not built to
|
|
// avoid collisions.
|
|
let mut state = SipHasher::new();
|
|
debug!("state: {:?}", state);
|
|
|
|
// FIXME(#32753) -- at (*) we `to_le` for endianness, but is
|
|
// this enough, and does it matter anyway?
|
|
"crate_disambiguator".hash(&mut state);
|
|
crate_disambiguator.len().to_le().hash(&mut state); // (*)
|
|
crate_disambiguator.hash(&mut state);
|
|
|
|
debug!("crate_disambiguator: {:?}", crate_disambiguator);
|
|
debug!("state: {:?}", state);
|
|
|
|
{
|
|
let mut visit = StrictVersionHashVisitor::new(&mut state, self);
|
|
krate.visit_all_items(&mut visit);
|
|
}
|
|
|
|
// FIXME (#14132): This hash is still sensitive to e.g. the
|
|
// spans of the crate Attributes and their underlying
|
|
// MetaItems; we should make ContentHashable impl for those
|
|
// types and then use hash_content. But, since all crate
|
|
// attributes should appear near beginning of the file, it is
|
|
// not such a big deal to be sensitive to their spans for now.
|
|
//
|
|
// We hash only the MetaItems instead of the entire Attribute
|
|
// to avoid hashing the AttrId
|
|
for attr in &krate.attrs {
|
|
debug!("krate attr {:?}", attr);
|
|
attr.node.value.hash(&mut state);
|
|
}
|
|
|
|
Svh::new(state.finish())
|
|
}
|
|
|
|
fn calculate_item_hash(self, def_id: DefId) -> u64 {
|
|
assert!(def_id.is_local());
|
|
|
|
debug!("calculate_item_hash(def_id={:?})", def_id);
|
|
|
|
let mut state = SipHasher::new();
|
|
|
|
{
|
|
let mut visit = StrictVersionHashVisitor::new(&mut state, self);
|
|
if def_id.index == CRATE_DEF_INDEX {
|
|
// the crate root itself is not registered in the map
|
|
// as an item, so we have to fetch it this way
|
|
let krate = self.map.krate();
|
|
intravisit::walk_crate(&mut visit, krate);
|
|
} else {
|
|
let node_id = self.map.as_local_node_id(def_id).unwrap();
|
|
let item = self.map.expect_item(node_id);
|
|
visit.visit_item(item);
|
|
}
|
|
}
|
|
|
|
let hash = state.finish();
|
|
|
|
debug!("calculate_item_hash: def_id={:?} hash={:?}", def_id, hash);
|
|
|
|
hash
|
|
}
|
|
}
|
|
|
|
// FIXME (#14132): Even this SVH computation still has implementation
|
|
// artifacts: namely, the order of item declaration will affect the
|
|
// hash computation, but for many kinds of items the order of
|
|
// declaration should be irrelevant to the ABI.
|
|
|
|
mod svh_visitor {
|
|
pub use self::SawExprComponent::*;
|
|
pub use self::SawStmtComponent::*;
|
|
use self::SawAbiComponent::*;
|
|
use syntax::ast::{self, Name, NodeId};
|
|
use syntax::parse::token;
|
|
use syntax_pos::Span;
|
|
use rustc::ty::TyCtxt;
|
|
use rustc::hir;
|
|
use rustc::hir::*;
|
|
use rustc::hir::map::DefPath;
|
|
use rustc::hir::intravisit as visit;
|
|
use rustc::hir::intravisit::{Visitor, FnKind};
|
|
|
|
use std::hash::{Hash, SipHasher};
|
|
|
|
pub struct StrictVersionHashVisitor<'a, 'tcx: 'a> {
|
|
pub tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
|
pub st: &'a mut SipHasher,
|
|
}
|
|
|
|
impl<'a, 'tcx> StrictVersionHashVisitor<'a, 'tcx> {
|
|
pub fn new(st: &'a mut SipHasher,
|
|
tcx: TyCtxt<'a, 'tcx, 'tcx>)
|
|
-> Self {
|
|
StrictVersionHashVisitor { st: st, tcx: tcx }
|
|
}
|
|
|
|
fn hash_def_path(&mut self, path: &DefPath) {
|
|
self.tcx.crate_name(path.krate).hash(self.st);
|
|
self.tcx.crate_disambiguator(path.krate).hash(self.st);
|
|
for data in &path.data {
|
|
data.data.as_interned_str().hash(self.st);
|
|
data.disambiguator.hash(self.st);
|
|
}
|
|
}
|
|
}
|
|
|
|
// To off-load the bulk of the hash-computation on #[derive(Hash)],
|
|
// we define a set of enums corresponding to the content that our
|
|
// crate visitor will encounter as it traverses the ast.
|
|
//
|
|
// The important invariant is that all of the Saw*Component enums
|
|
// do not carry any Spans, Names, or Idents.
|
|
//
|
|
// Not carrying any Names/Idents is the important fix for problem
|
|
// noted on PR #13948: using the ident.name as the basis for a
|
|
// hash leads to unstable SVH, because ident.name is just an index
|
|
// into intern table (i.e. essentially a random address), not
|
|
// computed from the name content.
|
|
//
|
|
// With the below enums, the SVH computation is not sensitive to
|
|
// artifacts of how rustc was invoked nor of how the source code
|
|
// was laid out. (Or at least it is *less* sensitive.)
|
|
|
|
// This enum represents the different potential bits of code the
|
|
// visitor could encounter that could affect the ABI for the crate,
|
|
// and assigns each a distinct tag to feed into the hash computation.
|
|
#[derive(Hash)]
|
|
enum SawAbiComponent<'a> {
|
|
|
|
// FIXME (#14132): should we include (some function of)
|
|
// ident.ctxt as well?
|
|
SawIdent(token::InternedString),
|
|
SawStructDef(token::InternedString),
|
|
|
|
SawLifetime(token::InternedString),
|
|
SawLifetimeDef(token::InternedString),
|
|
|
|
SawMod,
|
|
SawForeignItem,
|
|
SawItem,
|
|
SawDecl,
|
|
SawTy,
|
|
SawGenerics,
|
|
SawFn,
|
|
SawTraitItem,
|
|
SawImplItem,
|
|
SawStructField,
|
|
SawVariant,
|
|
SawPath,
|
|
SawBlock,
|
|
SawPat,
|
|
SawLocal,
|
|
SawArm,
|
|
SawExpr(SawExprComponent<'a>),
|
|
SawStmt(SawStmtComponent),
|
|
}
|
|
|
|
/// SawExprComponent carries all of the information that we want
|
|
/// to include in the hash that *won't* be covered by the
|
|
/// subsequent recursive traversal of the expression's
|
|
/// substructure by the visitor.
|
|
///
|
|
/// We know every Expr_ variant is covered by a variant because
|
|
/// `fn saw_expr` maps each to some case below. Ensuring that
|
|
/// each variant carries an appropriate payload has to be verified
|
|
/// by hand.
|
|
///
|
|
/// (However, getting that *exactly* right is not so important
|
|
/// because the SVH is just a developer convenience; there is no
|
|
/// guarantee of collision-freedom, hash collisions are just
|
|
/// (hopefully) unlikely.)
|
|
#[derive(Hash)]
|
|
pub enum SawExprComponent<'a> {
|
|
|
|
SawExprLoop(Option<token::InternedString>),
|
|
SawExprField(token::InternedString),
|
|
SawExprTupField(usize),
|
|
SawExprBreak(Option<token::InternedString>),
|
|
SawExprAgain(Option<token::InternedString>),
|
|
|
|
SawExprBox,
|
|
SawExprVec,
|
|
SawExprCall,
|
|
SawExprMethodCall,
|
|
SawExprTup,
|
|
SawExprBinary(hir::BinOp_),
|
|
SawExprUnary(hir::UnOp),
|
|
SawExprLit(ast::LitKind),
|
|
SawExprCast,
|
|
SawExprType,
|
|
SawExprIf,
|
|
SawExprWhile,
|
|
SawExprMatch,
|
|
SawExprClosure,
|
|
SawExprBlock,
|
|
SawExprAssign,
|
|
SawExprAssignOp(hir::BinOp_),
|
|
SawExprIndex,
|
|
SawExprPath(Option<usize>),
|
|
SawExprAddrOf(hir::Mutability),
|
|
SawExprRet,
|
|
SawExprInlineAsm(&'a hir::InlineAsm),
|
|
SawExprStruct,
|
|
SawExprRepeat,
|
|
}
|
|
|
|
fn saw_expr<'a>(node: &'a Expr_) -> SawExprComponent<'a> {
|
|
match *node {
|
|
ExprBox(..) => SawExprBox,
|
|
ExprVec(..) => SawExprVec,
|
|
ExprCall(..) => SawExprCall,
|
|
ExprMethodCall(..) => SawExprMethodCall,
|
|
ExprTup(..) => SawExprTup,
|
|
ExprBinary(op, _, _) => SawExprBinary(op.node),
|
|
ExprUnary(op, _) => SawExprUnary(op),
|
|
ExprLit(ref lit) => SawExprLit(lit.node.clone()),
|
|
ExprCast(..) => SawExprCast,
|
|
ExprType(..) => SawExprType,
|
|
ExprIf(..) => SawExprIf,
|
|
ExprWhile(..) => SawExprWhile,
|
|
ExprLoop(_, id) => SawExprLoop(id.map(|id| id.node.as_str())),
|
|
ExprMatch(..) => SawExprMatch,
|
|
ExprClosure(..) => SawExprClosure,
|
|
ExprBlock(..) => SawExprBlock,
|
|
ExprAssign(..) => SawExprAssign,
|
|
ExprAssignOp(op, _, _) => SawExprAssignOp(op.node),
|
|
ExprField(_, name) => SawExprField(name.node.as_str()),
|
|
ExprTupField(_, id) => SawExprTupField(id.node),
|
|
ExprIndex(..) => SawExprIndex,
|
|
ExprPath(ref qself, _) => SawExprPath(qself.as_ref().map(|q| q.position)),
|
|
ExprAddrOf(m, _) => SawExprAddrOf(m),
|
|
ExprBreak(id) => SawExprBreak(id.map(|id| id.node.as_str())),
|
|
ExprAgain(id) => SawExprAgain(id.map(|id| id.node.as_str())),
|
|
ExprRet(..) => SawExprRet,
|
|
ExprInlineAsm(ref a,_,_) => SawExprInlineAsm(a),
|
|
ExprStruct(..) => SawExprStruct,
|
|
ExprRepeat(..) => SawExprRepeat,
|
|
}
|
|
}
|
|
|
|
/// SawStmtComponent is analogous to SawExprComponent, but for statements.
|
|
#[derive(Hash)]
|
|
pub enum SawStmtComponent {
|
|
SawStmtDecl,
|
|
SawStmtExpr,
|
|
SawStmtSemi,
|
|
}
|
|
|
|
fn saw_stmt(node: &Stmt_) -> SawStmtComponent {
|
|
match *node {
|
|
StmtDecl(..) => SawStmtDecl,
|
|
StmtExpr(..) => SawStmtExpr,
|
|
StmtSemi(..) => SawStmtSemi,
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx> Visitor<'a> for StrictVersionHashVisitor<'a, 'tcx> {
|
|
fn visit_nested_item(&mut self, item: ItemId) {
|
|
let def_path = self.tcx.map.def_path_from_id(item.id).unwrap();
|
|
debug!("visit_nested_item: def_path={:?} st={:?}", def_path, self.st);
|
|
self.hash_def_path(&def_path);
|
|
}
|
|
|
|
fn visit_variant_data(&mut self, s: &'a VariantData, name: Name,
|
|
g: &'a Generics, _: NodeId, _: Span) {
|
|
debug!("visit_variant_data: st={:?}", self.st);
|
|
SawStructDef(name.as_str()).hash(self.st);
|
|
visit::walk_generics(self, g);
|
|
visit::walk_struct_def(self, s)
|
|
}
|
|
|
|
fn visit_variant(&mut self, v: &'a Variant, g: &'a Generics, item_id: NodeId) {
|
|
debug!("visit_variant: st={:?}", self.st);
|
|
SawVariant.hash(self.st);
|
|
// walk_variant does not call walk_generics, so do it here.
|
|
visit::walk_generics(self, g);
|
|
visit::walk_variant(self, v, g, item_id)
|
|
}
|
|
|
|
// All of the remaining methods just record (in the hash
|
|
// SipHasher) that the visitor saw that particular variant
|
|
// (with its payload), and continue walking as the default
|
|
// visitor would.
|
|
//
|
|
// Some of the implementations have some notes as to how one
|
|
// might try to make their SVH computation less discerning
|
|
// (e.g. by incorporating reachability analysis). But
|
|
// currently all of their implementations are uniform and
|
|
// uninteresting.
|
|
//
|
|
// (If you edit a method such that it deviates from the
|
|
// pattern, please move that method up above this comment.)
|
|
|
|
fn visit_name(&mut self, _: Span, name: Name) {
|
|
debug!("visit_name: st={:?}", self.st);
|
|
SawIdent(name.as_str()).hash(self.st);
|
|
}
|
|
|
|
fn visit_lifetime(&mut self, l: &'a Lifetime) {
|
|
debug!("visit_lifetime: st={:?}", self.st);
|
|
SawLifetime(l.name.as_str()).hash(self.st);
|
|
}
|
|
|
|
fn visit_lifetime_def(&mut self, l: &'a LifetimeDef) {
|
|
debug!("visit_lifetime_def: st={:?}", self.st);
|
|
SawLifetimeDef(l.lifetime.name.as_str()).hash(self.st);
|
|
}
|
|
|
|
// We do recursively walk the bodies of functions/methods
|
|
// (rather than omitting their bodies from the hash) since
|
|
// monomorphization and cross-crate inlining generally implies
|
|
// that a change to a crate body will require downstream
|
|
// crates to be recompiled.
|
|
fn visit_expr(&mut self, ex: &'a Expr) {
|
|
debug!("visit_expr: st={:?}", self.st);
|
|
SawExpr(saw_expr(&ex.node)).hash(self.st); visit::walk_expr(self, ex)
|
|
}
|
|
|
|
fn visit_stmt(&mut self, s: &'a Stmt) {
|
|
debug!("visit_stmt: st={:?}", self.st);
|
|
SawStmt(saw_stmt(&s.node)).hash(self.st); visit::walk_stmt(self, s)
|
|
}
|
|
|
|
fn visit_foreign_item(&mut self, i: &'a ForeignItem) {
|
|
debug!("visit_foreign_item: st={:?}", self.st);
|
|
|
|
// FIXME (#14132) ideally we would incorporate privacy (or
|
|
// perhaps reachability) somewhere here, so foreign items
|
|
// that do not leak into downstream crates would not be
|
|
// part of the ABI.
|
|
SawForeignItem.hash(self.st); visit::walk_foreign_item(self, i)
|
|
}
|
|
|
|
fn visit_item(&mut self, i: &'a Item) {
|
|
debug!("visit_item: {:?} st={:?}", i, self.st);
|
|
|
|
// FIXME (#14132) ideally would incorporate reachability
|
|
// analysis somewhere here, so items that never leak into
|
|
// downstream crates (e.g. via monomorphisation or
|
|
// inlining) would not be part of the ABI.
|
|
SawItem.hash(self.st); visit::walk_item(self, i)
|
|
}
|
|
|
|
fn visit_mod(&mut self, m: &'a Mod, _s: Span, n: NodeId) {
|
|
debug!("visit_mod: st={:?}", self.st);
|
|
SawMod.hash(self.st); visit::walk_mod(self, m, n)
|
|
}
|
|
|
|
fn visit_decl(&mut self, d: &'a Decl) {
|
|
debug!("visit_decl: st={:?}", self.st);
|
|
SawDecl.hash(self.st); visit::walk_decl(self, d)
|
|
}
|
|
|
|
fn visit_ty(&mut self, t: &'a Ty) {
|
|
debug!("visit_ty: st={:?}", self.st);
|
|
SawTy.hash(self.st); visit::walk_ty(self, t)
|
|
}
|
|
|
|
fn visit_generics(&mut self, g: &'a Generics) {
|
|
debug!("visit_generics: st={:?}", self.st);
|
|
SawGenerics.hash(self.st); visit::walk_generics(self, g)
|
|
}
|
|
|
|
fn visit_fn(&mut self, fk: FnKind<'a>, fd: &'a FnDecl,
|
|
b: &'a Block, s: Span, n: NodeId) {
|
|
debug!("visit_fn: st={:?}", self.st);
|
|
SawFn.hash(self.st); visit::walk_fn(self, fk, fd, b, s, n)
|
|
}
|
|
|
|
fn visit_trait_item(&mut self, ti: &'a TraitItem) {
|
|
debug!("visit_trait_item: st={:?}", self.st);
|
|
SawTraitItem.hash(self.st); visit::walk_trait_item(self, ti)
|
|
}
|
|
|
|
fn visit_impl_item(&mut self, ii: &'a ImplItem) {
|
|
debug!("visit_impl_item: st={:?}", self.st);
|
|
SawImplItem.hash(self.st); visit::walk_impl_item(self, ii)
|
|
}
|
|
|
|
fn visit_struct_field(&mut self, s: &'a StructField) {
|
|
debug!("visit_struct_field: st={:?}", self.st);
|
|
SawStructField.hash(self.st); visit::walk_struct_field(self, s)
|
|
}
|
|
|
|
fn visit_path(&mut self, path: &'a Path, _: ast::NodeId) {
|
|
debug!("visit_path: st={:?}", self.st);
|
|
SawPath.hash(self.st); visit::walk_path(self, path)
|
|
}
|
|
|
|
fn visit_block(&mut self, b: &'a Block) {
|
|
debug!("visit_block: st={:?}", self.st);
|
|
SawBlock.hash(self.st); visit::walk_block(self, b)
|
|
}
|
|
|
|
fn visit_pat(&mut self, p: &'a Pat) {
|
|
debug!("visit_pat: st={:?}", self.st);
|
|
SawPat.hash(self.st); visit::walk_pat(self, p)
|
|
}
|
|
|
|
fn visit_local(&mut self, l: &'a Local) {
|
|
debug!("visit_local: st={:?}", self.st);
|
|
SawLocal.hash(self.st); visit::walk_local(self, l)
|
|
}
|
|
|
|
fn visit_arm(&mut self, a: &'a Arm) {
|
|
debug!("visit_arm: st={:?}", self.st);
|
|
SawArm.hash(self.st); visit::walk_arm(self, a)
|
|
}
|
|
}
|
|
}
|