charon_lib/ast/
ullbc_ast.rs

1//! "Unstructured LLBC" ast (ULLBC). This is LLBC before the control-flow
2//! reconstruction. In effect, this is a cleaned up version of MIR.
3pub use crate::ast::*;
4use crate::ids::IndexVec;
5use derive_generic_visitor::{Drive, DriveMut};
6use macros::{EnumAsGetters, EnumIsA, VariantIndexArity, VariantName};
7use serde_state::{DeserializeState, SerializeState};
8
9// Block identifier. Similar to rust's `BasicBlock`.
10generate_index_type!(BlockId, "Block");
11
12// The entry block of a function is always the block with id 0
13pub static START_BLOCK_ID: BlockId = BlockId::ZERO;
14
15#[cfg_attr(feature = "charon_on_charon", charon::rename("Blocks"))]
16pub type BodyContents = IndexVec<BlockId, BlockData>;
17pub type ExprBody = GExprBody<BodyContents>;
18
19/// A raw statement: a statement without meta data.
20#[derive(
21    Debug,
22    PartialEq,
23    Eq,
24    Clone,
25    EnumIsA,
26    EnumAsGetters,
27    VariantName,
28    SerializeState,
29    DeserializeState,
30    Drive,
31    DriveMut,
32)]
33pub enum StatementKind {
34    Assign(Place, Rvalue),
35    /// A call. For now, we don't support dynamic calls (i.e. to a function pointer in memory).
36    SetDiscriminant(Place, VariantId),
37    /// Equivalent to std::intrinsics::copy_nonoverlapping; this is not modelled as a function
38    /// call as it cannot diverge
39    CopyNonOverlapping(Box<CopyNonOverlapping>),
40    /// Indicates that this local should be allocated; if it is already allocated, this frees
41    /// the local and re-allocates it. The arguments do not receive a `StorageLive`. We ensure in
42    /// the micro-pass `insert_storage_statements` that all other locals have a `StorageLive`
43    /// associated with them.
44    StorageLive(LocalId),
45    /// Indicates that this local should be deallocated; if it is already deallocated, this is
46    /// a no-op. A local may not have a `StorageDead` in the function's body, in which case it
47    /// is implicitly deallocated at the end of the function. The return local does not receive a
48    /// `StorageDead`. We ensure in the micro-pass `insert_storage_statements` that all other locals
49    /// have a `StorageDead` before function exits.
50    StorageDead(LocalId),
51    /// A place is mentioned, but not accessed. The place itself must still be valid though, so
52    /// this statement is not a no-op: it can trigger UB if the place's projections are not valid
53    /// (e.g. because they go out of bounds).
54    PlaceMention(Place),
55    /// A non-diverging runtime check for a condition. This can be either:
56    /// - Emitted for inlined "assumes" (which cause UB on failure)
57    /// - Reconstructed from `if b { panic() }` if `--reconstruct-asserts` is set.
58    ///
59    /// This statement comes with the effect that happens when the check fails
60    /// (rather than representing it as an unwinding edge).
61    Assert {
62        assert: Assert,
63        on_failure: AbortKind,
64    },
65    /// Does nothing. Useful for passes.
66    Nop,
67}
68
69#[derive(Debug, PartialEq, Eq, Clone, SerializeState, DeserializeState, Drive, DriveMut)]
70pub struct Statement {
71    pub span: Span,
72    pub kind: StatementKind,
73    /// Comments that precede this statement.
74    // This is filled in a late pass after all the control-flow manipulation.
75    #[drive(skip)]
76    pub comments_before: Vec<String>,
77}
78
79#[derive(
80    Debug,
81    PartialEq,
82    Eq,
83    Clone,
84    EnumIsA,
85    EnumAsGetters,
86    VariantName,
87    VariantIndexArity,
88    SerializeState,
89    DeserializeState,
90    Drive,
91    DriveMut,
92)]
93#[cfg_attr(feature = "charon_on_charon", charon::rename("Switch"))]
94pub enum SwitchTargets {
95    /// Gives the `if` block and the `else` block
96    If(BlockId, BlockId),
97    /// Gives the integer type, a map linking values to switch branches, and the
98    /// otherwise block. Note that matches over enumerations are performed by
99    /// switching over the discriminant, which is an integer.
100    SwitchInt(LiteralTy, Vec<(Literal, BlockId)>, BlockId),
101}
102
103/// A raw terminator: a terminator without meta data.
104#[derive(
105    Debug,
106    PartialEq,
107    Eq,
108    Clone,
109    EnumIsA,
110    EnumAsGetters,
111    SerializeState,
112    DeserializeState,
113    Drive,
114    DriveMut,
115)]
116pub enum TerminatorKind {
117    Goto {
118        target: BlockId,
119    },
120    Switch {
121        discr: Operand,
122        targets: SwitchTargets,
123    },
124    Call {
125        call: Call,
126        target: BlockId,
127        on_unwind: BlockId,
128    },
129    /// Drop the value at the given place.
130    ///
131    /// Depending on `DropKind`, this may be a real call to `drop_glue`, or a conditional call
132    /// that should only happen if the place has not been moved out of. See the docs of `DropKind`
133    /// for more details; to get precise drops use `--precise-drops`.
134    Drop {
135        #[drive(skip)]
136        kind: DropKind,
137        place: Place,
138        /// Reference to the `drop_glue` code to call on drop.
139        fn_ptr: FnPtr,
140        target: BlockId,
141        on_unwind: BlockId,
142    },
143    /// Assert that the given condition holds, and if not, unwind to the given block. This is used for
144    /// bounds checks, overflow checks, etc.
145    #[cfg_attr(feature = "charon_on_charon", charon::rename("TAssert"))]
146    Assert {
147        assert: Assert,
148        target: BlockId,
149        on_unwind: BlockId,
150    },
151    /// An inline assembly block. For now we only preserve the template string.
152    InlineAsm {
153        asm: String,
154        targets: Vec<BlockId>,
155        on_unwind: BlockId,
156    },
157    /// Handles panics and impossible cases.
158    Abort(AbortKind),
159    Return,
160    /// Unwind out of the current function into its caller.
161    UnwindResume,
162}
163
164#[derive(Debug, PartialEq, Eq, Clone, SerializeState, DeserializeState, Drive, DriveMut)]
165pub struct Terminator {
166    pub span: Span,
167    pub kind: TerminatorKind,
168    /// Comments that precede this terminator.
169    // This is filled in a late pass after all the control-flow manipulation.
170    #[drive(skip)]
171    pub comments_before: Vec<String>,
172}
173
174#[derive(Debug, PartialEq, Eq, Clone, SerializeState, DeserializeState, Drive, DriveMut)]
175#[cfg_attr(feature = "charon_on_charon", charon::rename("Block"))]
176pub struct BlockData {
177    pub statements: Vec<Statement>,
178    pub terminator: Terminator,
179}
charon_lib/ast/ullbc_ast.rs

charon_lib/ast/
ullbc_ast.rs
