charon_lib/ast/
llbc_ast.rs

1//! LLBC
2//!
3//! MIR code where we have rebuilt the control-flow (`if ... then ... else ...`,
4//! `while ...`, ...).
5//!
6//! Also note that we completely break the definitions Statement and Terminator
7//! from MIR to use Statement only.
8
9pub use super::llbc_ast_utils::*;
10pub use crate::ast::*;
11use derive_generic_visitor::{Drive, DriveMut};
12use macros::{EnumAsGetters, EnumIsA, EnumToGetters, VariantIndexArity, VariantName};
13use serde::{Deserialize, Serialize};
14
15generate_index_type!(StatementId);
16
17/// A raw statement: a statement without meta data.
18#[derive(
19    Debug, Clone, EnumIsA, EnumToGetters, EnumAsGetters, Serialize, Deserialize, Drive, DriveMut,
20)]
21pub enum RawStatement {
22    /// Assigns an `Rvalue` to a `Place`. e.g. `let y = x;` could become
23    /// `y := move x` which is represented as `Assign(y, Rvalue::Use(Operand::Move(x)))`.
24    Assign(Place, Rvalue),
25    /// Not used today because we take MIR built.
26    SetDiscriminant(Place, VariantId),
27    /// Equivalent to std::intrinsics::copy_nonoverlapping; this is not modelled as a function
28    /// call as it cannot diverge
29    CopyNonOverlapping(Box<CopyNonOverlapping>),
30    /// Indicates that this local should be allocated; if it is already allocated, this frees
31    /// the local and re-allocates it. The return value and arguments do not receive a
32    /// `StorageLive`. We ensure in the micro-pass `insert_storage_lives` that all other locals
33    /// have a `StorageLive` associated with them.
34    StorageLive(LocalId),
35    /// Indicates that this local should be deallocated; if it is already deallocated, this is
36    /// a no-op. A local may not have a `StorageDead` in the function's body, in which case it
37    /// is implicitly deallocated at the end of the function.
38    StorageDead(LocalId),
39    Deinit(Place),
40    /// Drop the value at the given place.
41    ///
42    /// For MIR built and promoted, this is a conditional drop: the value will only be dropped if
43    /// it has not already been moved out. For MIR elaborated and optimized, this is a real drop.
44    ///
45    /// This drop is then equivalent to a call to `std::ptr::drop_in_place(&raw mut place)`.
46    Drop(Place, TraitRef),
47    Assert(Assert),
48    Call(Call),
49    /// Panic also handles "unreachable". We keep the name of the panicking function that was
50    /// called.
51    Abort(AbortKind),
52    Return,
53    /// Break to outer loops.
54    /// The `usize` gives the index of the outer loop to break to:
55    /// * 0: break to first outer loop (the current loop)
56    /// * 1: break to second outer loop
57    /// * ...
58    #[drive(skip)]
59    Break(usize),
60    /// Continue to outer loops.
61    /// The `usize` gives the index of the outer loop to continue to:
62    /// * 0: continue to first outer loop (the current loop)
63    /// * 1: continue to second outer loop
64    /// * ...
65    #[drive(skip)]
66    Continue(usize),
67    /// No-op.
68    Nop,
69    Switch(Switch),
70    Loop(Block),
71    #[drive(skip)]
72    Error(String),
73}
74
75#[derive(Debug, Clone, Serialize, Deserialize, Drive, DriveMut)]
76pub struct Statement {
77    pub span: Span,
78    /// Integer uniquely identifying this statement among the statmeents in the current body. To
79    /// simplify things we generate globally-fresh ids when creating a new `Statement`.
80    #[charon::rename("statement_id")]
81    pub id: StatementId,
82    pub content: RawStatement,
83    /// Comments that precede this statement.
84    // This is filled in a late pass after all the control-flow manipulation.
85    #[drive(skip)]
86    pub comments_before: Vec<String>,
87}
88
89#[derive(Debug, Clone, Serialize, Deserialize, Drive, DriveMut)]
90pub struct Block {
91    pub span: Span,
92    pub statements: Vec<Statement>,
93}
94
95#[derive(
96    Debug,
97    Clone,
98    EnumIsA,
99    EnumToGetters,
100    EnumAsGetters,
101    Serialize,
102    Deserialize,
103    Drive,
104    DriveMut,
105    VariantName,
106    VariantIndexArity,
107)]
108pub enum Switch {
109    /// Gives the `if` block and the `else` block. The `Operand` is the condition of the `if`, e.g. `if (y == 0)` could become
110    /// ```text
111    /// v@3 := copy y; // Represented as `Assign(v@3, Use(Copy(y))`
112    /// v@2 := move v@3 == 0; // Represented as `Assign(v@2, BinOp(BinOp::Eq, Move(y), Const(0)))`
113    /// if (move v@2) { // Represented as `If(Move(v@2), <then branch>, <else branch>)`
114    /// ```
115    If(Operand, Block, Block),
116    /// Gives the integer type, a map linking values to switch branches, and the
117    /// otherwise block. Note that matches over enumerations are performed by
118    /// switching over the discriminant, which is an integer.
119    /// Also, we use a `Vec` to make sure the order of the switch
120    /// branches is preserved.
121    ///
122    /// Rk.: we use a vector of values, because some of the branches may
123    /// be grouped together, like for the following code:
124    /// ```text
125    /// match e {
126    ///   E::V1 | E::V2 => ..., // Grouped
127    ///   E::V3 => ...
128    /// }
129    /// ```
130    SwitchInt(Operand, IntegerTy, Vec<(Vec<ScalarValue>, Block)>, Block),
131    /// A match over an ADT.
132    ///
133    /// The match statement is introduced in [crate::transform::remove_read_discriminant]
134    /// (whenever we find a discriminant read, we merge it with the subsequent
135    /// switch into a match).
136    Match(Place, Vec<(Vec<VariantId>, Block)>, Option<Block>),
137}
138
139pub type ExprBody = GExprBody<Block>;
charon_lib/ast/llbc_ast.rs

charon_lib/ast/
llbc_ast.rs
