charon_lib/transform/mod.rs
1pub mod check_generics;
2pub mod compute_short_names;
3pub mod ctx;
4pub mod duplicate_defaulted_methods;
5pub mod duplicate_return;
6pub mod expand_associated_types;
7pub mod filter_invisible_trait_impls;
8pub mod filter_unreachable_blocks;
9pub mod graphs;
10pub mod hide_marker_traits;
11pub mod index_intermediate_assigns;
12pub mod index_to_function_calls;
13pub mod inline_local_panic_functions;
14pub mod inline_promoted_consts;
15pub mod insert_assign_return_unit;
16pub mod insert_storage_lives;
17pub mod lift_associated_item_clauses;
18pub mod merge_goto_chains;
19pub mod monomorphize;
20pub mod ops_to_function_calls;
21pub mod prettify_cfg;
22pub mod reconstruct_asserts;
23pub mod reconstruct_boxes;
24pub mod recover_body_comments;
25pub mod remove_drop_never;
26pub mod remove_dynamic_checks;
27pub mod remove_nops;
28pub mod remove_read_discriminant;
29pub mod remove_unit_locals;
30pub mod remove_unused_locals;
31pub mod remove_unused_methods;
32pub mod remove_unused_self_clause;
33pub mod reorder_decls;
34pub mod simplify_constants;
35pub mod skip_trait_refs_when_known;
36pub mod ullbc_to_llbc;
37pub mod unbind_item_vars;
38pub mod update_block_indices;
39pub mod utils;
40
41pub use ctx::TransformCtx;
42use ctx::{LlbcPass, TransformPass, UllbcPass};
43use Pass::*;
44
45/// Item and type cleanup passes.
46pub static INITIAL_CLEANUP_PASSES: &[Pass] = &[
47 // Compute short names
48 NonBody(&compute_short_names::Transform),
49 // Remove the trait/impl methods that were not translated (because not used).
50 NonBody(&remove_unused_methods::Transform),
51 // Move clauses on associated types to be parent clauses
52 NonBody(&lift_associated_item_clauses::Transform),
53 // Check that all supplied generic types match the corresponding generic parameters.
54 // Needs `lift_associated_item_clauses`.
55 NonBody(&check_generics::Check("after translation")),
56 // # Micro-pass: hide some overly-common traits we don't need: Sized, Sync, Allocator, etc..
57 NonBody(&hide_marker_traits::Transform),
58 // # Micro-pass: filter the trait impls that were marked invisible since we couldn't filter
59 // them out earlier.
60 NonBody(&filter_invisible_trait_impls::Transform),
61 // # Micro-pass: remove the explicit `Self: Trait` clause of methods/assoc const declaration
62 // items if they're not used. This simplifies the graph of dependencies between definitions.
63 NonBody(&remove_unused_self_clause::Transform),
64 // Add missing methods to trait impls by duplicating the default method.
65 NonBody(&duplicate_defaulted_methods::Transform),
66 // # Micro-pass: whenever we call a trait method on a known type, refer to the method `FunDecl`
67 // directly instead of going via a `TraitRef`. This is done before `reorder_decls` to remove
68 // some sources of mutual recursion.
69 UnstructuredBody(&skip_trait_refs_when_known::Transform),
70 // Change trait associated types to be type parameters instead. See the module for details.
71 NonBody(&expand_associated_types::Transform),
72];
73
74/// Body cleanup passes on the ullbc.
75pub static ULLBC_PASSES: &[Pass] = &[
76 // Inline promoted consts into their parent bodies.
77 UnstructuredBody(&inline_promoted_consts::Transform),
78 // # Micro-pass: merge single-origin gotos into their parent. This drastically reduces the
79 // graph size of the CFG.
80 UnstructuredBody(&merge_goto_chains::Transform),
81 // # Micro-pass: Remove overflow/div-by-zero/bounds checks since they are already part of the
82 // arithmetic/array operation in the semantics of (U)LLBC.
83 // **WARNING**: this pass uses the fact that the dynamic checks introduced by Rustc use a
84 // special "assert" construct. Because of this, it must happen *before* the
85 // [reconstruct_asserts] pass. See the comments in [crate::remove_dynamic_checks].
86 // **WARNING**: this pass relies on a precise structure of the MIR statements. Because of this,
87 // it must happen before passes that insert statements like [simplify_constants].
88 UnstructuredBody(&remove_dynamic_checks::Transform),
89 // # Micro-pass: reconstruct the special `Box::new` operations inserted e.g. in the `vec![]`
90 // macro.
91 // **WARNING**: this pass relies on a precise structure of the MIR statements. Because of this,
92 // it must happen before passes that insert statements like [simplify_constants].
93 // **WARNING**: this pass works across calls, hence must happen after `merge_goto_chains`,
94 UnstructuredBody(&reconstruct_boxes::Transform),
95 // # Micro-pass: desugar the constants to other values/operands as much
96 // as possible.
97 UnstructuredBody(&simplify_constants::Transform),
98 // # Micro-pass: make sure the block ids used in the ULLBC are consecutive
99 UnstructuredBody(&update_block_indices::Transform),
100 // # Micro-pass: reconstruct the asserts
101 UnstructuredBody(&reconstruct_asserts::Transform),
102 // # Micro-pass: duplicate the return blocks
103 UnstructuredBody(&duplicate_return::Transform),
104 // # Micro-pass: filter the "dangling" blocks. Those might have been introduced by,
105 // for instance, [`reconstruct_asserts`].
106 UnstructuredBody(&filter_unreachable_blocks::Transform),
107 // # Micro-pass: `panic!()` expands to a new function definition each time. This pass cleans
108 // those up.
109 UnstructuredBody(&inline_local_panic_functions::Transform),
110 // # Micro-pass: introduce intermediate assignments in preparation of the
111 // [`index_to_function_calls`] pass.
112 UnstructuredBody(&index_intermediate_assigns::Transform),
113 // # Micro-pass: add the missing assignments to the return value.
114 // When the function return type is unit, the generated MIR doesn't
115 // set the return value to `()`. This can be a concern: in the case
116 // of Aeneas, it means the return variable contains ⊥ upon returning.
117 // For this reason, when the function has return type unit, we insert
118 // an extra assignment just before returning.
119 UnstructuredBody(&insert_assign_return_unit::Transform),
120 // # Micro-pass: remove locals of type `()` which show up a lot.
121 UnstructuredBody(&remove_unit_locals::Transform),
122 // # Micro-pass: remove the drops of locals whose type is `Never` (`!`). This
123 // is in preparation of the next transformation.
124 UnstructuredBody(&remove_drop_never::Transform),
125];
126
127/// Body cleanup passes after control flow reconstruction.
128pub static LLBC_PASSES: &[Pass] = &[
129 // # Go from ULLBC to LLBC (Low-Level Borrow Calculus) by reconstructing the control flow.
130 NonBody(&ullbc_to_llbc::Transform),
131 // # Micro-pass: replace some unops/binops and the array aggregates with
132 // function calls (introduces: ArrayToSlice, etc.)
133 StructuredBody(&ops_to_function_calls::Transform),
134 // # Micro-pass: replace the arrays/slices index operations with function
135 // calls.
136 // (introduces: ArrayIndexShared, ArrayIndexMut, etc.)
137 StructuredBody(&index_to_function_calls::Transform),
138 // # Micro-pass: Remove the discriminant reads (merge them with the switches)
139 StructuredBody(&remove_read_discriminant::Transform),
140 // Cleanup the cfg.
141 StructuredBody(&prettify_cfg::Transform),
142];
143
144/// Cleanup passes useful for both llbc and ullbc.
145pub static SHARED_FINALIZING_PASSES: &[Pass] = &[
146 // # Micro-pass: remove the locals which are never used.
147 NonBody(&remove_unused_locals::Transform),
148 // Insert storage lives for locals that are always allocated at the beginning of the function.
149 NonBody(&insert_storage_lives::Transform),
150 // # Micro-pass: remove the useless `StatementKind::Nop`s.
151 NonBody(&remove_nops::Transform),
152 // Monomorphize the functions and types.
153 NonBody(&monomorphize::Transform),
154 // # Micro-pass: take all the comments found in the original body and assign them to
155 // statements. This must be last after all the statement-affecting passes to avoid losing
156 // comments.
157 NonBody(&recover_body_comments::Transform),
158 // # Reorder the graph of dependencies and compute the strictly connex components to:
159 // - compute the order in which to extract the definitions
160 // - find the recursive definitions
161 // - group the mutually recursive definitions
162 NonBody(&reorder_decls::Transform),
163];
164
165/// Final passes to run at the end, after pretty-printing the llbc if applicable. These are only
166/// split from the above list to get test outputs even when generics fail to match.
167pub static FINAL_CLEANUP_PASSES: &[Pass] = &[
168 // Check that all supplied generic types match the corresponding generic parameters.
169 NonBody(&check_generics::Check("after transformations")),
170 // Use `DeBruijnVar::Free` for the variables bound in item signatures.
171 NonBody(&unbind_item_vars::Check),
172];
173
174#[derive(Clone, Copy)]
175pub enum Pass {
176 NonBody(&'static dyn TransformPass),
177 UnstructuredBody(&'static dyn UllbcPass),
178 StructuredBody(&'static dyn LlbcPass),
179}
180
181impl Pass {
182 pub fn run(self, ctx: &mut TransformCtx) {
183 match self {
184 NonBody(pass) => pass.transform_ctx(ctx),
185 UnstructuredBody(pass) => pass.transform_ctx(ctx),
186 StructuredBody(pass) => pass.transform_ctx(ctx),
187 }
188 }
189
190 pub fn name(&self) -> &str {
191 match self {
192 NonBody(pass) => pass.name(),
193 UnstructuredBody(pass) => pass.name(),
194 StructuredBody(pass) => pass.name(),
195 }
196 }
197}
198
199pub struct PrintCtxPass {
200 pub message: String,
201 /// Whether we're printing to stdout or only logging.
202 pub to_stdout: bool,
203}
204
205impl PrintCtxPass {
206 pub fn new(to_stdout: bool, message: String) -> &'static Self {
207 let ret = Self { message, to_stdout };
208 Box::leak(Box::new(ret))
209 }
210}
211
212impl TransformPass for PrintCtxPass {
213 fn transform_ctx(&self, ctx: &mut TransformCtx) {
214 let message = &self.message;
215 if self.to_stdout {
216 println!("{message}:\n\n{ctx}\n");
217 } else {
218 trace!("{message}:\n\n{ctx}\n");
219 }
220 }
221}