ironwork_exec/lower/
mod.rs

1//! Lowering (docs/lir.md): a compiled program with every name resolved, every category decided and
2//! every transfer of control made explicit, as the LIR a VM runs and a load module holds.
3//!
4//! Lowered so far: storage, places, expressions and conditions, the arithmetic verbs, MOVE, IF,
5//! EVALUATE, DISPLAY, INITIALIZE, PERFORM, GO TO, GO TO DEPENDING ON, ALTER, EXIT, STOP RUN, GOBACK,
6//! CALL, CANCEL, ENTRY, INVOKE, SET, STRING, UNSTRING, INSPECT, SEARCH, ACCEPT, the file
7//! statements, intrinsic functions, independent segments, class definitions, USE AFTER
8//! EXCEPTION/ERROR, USE FOR DEBUGGING, JSON and XML GENERATE and PARSE, the EXEC blocks, SORT,
9//! MERGE, RELEASE and RETURN, the Report Writer, user-defined functions, and EXTERNAL and GLOBAL
10//! records, files and declaratives.
11//! Anything else is [`LowerError::Unsupported`], naming the construct.
12
13mod call;
14mod check;
15mod cics;
16mod class;
17mod cond;
18mod data;
19mod file;
20mod flow;
21mod function;
22mod markup;
23mod plans;
24mod report;
25mod scope;
26mod search;
27mod set;
28mod sort;
29mod sql;
30mod text;
31mod user_function;
32mod verify;
33
34#[cfg(test)]
35mod tests;
36
37pub use verify::verify;
38
39use crate::Compiled;
40use crate::layout::{Layout, Resolved};
41use crate::machine::Machine;
42use crate::unit::{AddProgram, Clock, Library, RunUnit};
43use rt::abend::AbendCode;
44use rt::lir::{self, AbendId, BlockId, ConstId, DebugId, PlaceId, RangeId, SymId};
45use std::collections::{BTreeSet, HashMap};
46use std::fmt;
47use syntax::Pos;
48use syntax::ast;
49use zarch::ebcdic::CodePage;
50
51/// Why a program does not lower.
52#[derive(Clone, Debug, PartialEq, Eq)]
53pub enum LowerError {
54    /// A construct this slice does not lower yet, and where the program uses it.
55    Unsupported(&'static str, Pos),
56    /// A table larger than the LIR's ids can index.
57    Exceeds(&'static str, Pos),
58    /// The lowered program fails [`verify`], which is a fault in lowering.
59    Invalid(String),
60}
61
62impl LowerError {
63    pub fn pos(&self) -> Pos {
64        match self {
65            Self::Unsupported(_, pos) | Self::Exceeds(_, pos) => *pos,
66            Self::Invalid(_) => Pos::default(),
67        }
68    }
69}
70
71impl fmt::Display for LowerError {
72    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
73        match self {
74            Self::Unsupported(what, _) => write!(f, "lowering: {what} is not lowered yet"),
75            Self::Exceeds(what, _) => write!(f, "lowering: {what} exceeds the LIR's limit"),
76            Self::Invalid(why) => write!(f, "lowering: the lowered program is invalid: {why}"),
77        }
78    }
79}
80
81impl From<LowerError> for syntax::Error {
82    fn from(e: LowerError) -> Self {
83        syntax::Error::at(e.pos(), e.to_string())
84    }
85}
86
87type R<T> = Result<T, LowerError>;
88
89fn unsupported<T>(what: &'static str, pos: Pos) -> R<T> {
90    Err(LowerError::Unsupported(what, pos))
91}
92
93/// The next index of a table, refused past `u32`.
94fn next_id<T>(table: &[T], what: &'static str) -> R<u32> {
95    u32::try_from(table.len()).map_err(|_| LowerError::Exceeds(what, Pos::default()))
96}
97
98fn push<T>(table: &mut Vec<T>, value: T, what: &'static str) -> R<u32> {
99    let id = next_id(table, what)?;
100    table.push(value);
101    Ok(id)
102}
103
104/// Lowers one compiled program, or a class definition with its data and methods. One that passes
105/// Check and uses only the constructs lowered so far lowers.
106pub fn lower(compiled: &Compiled) -> Result<lir::Program, LowerError> {
107    let mut l = Lower::new(compiled);
108    let id = l.sym(&compiled.program.id);
109    let sources = compiled.program.sources.iter().map(|s| l.sym(s)).collect();
110    let storage = l.storage()?;
111    let items = l.items()?;
112    l.services.files = l.files()?;
113    l.services.declaratives = l.declaratives()?;
114    l.services.scope = l.scope()?;
115    l.services.report = l.report_writer()?;
116    (l.sql, l.services.sqlca) = l.sql_table()?;
117    let paragraphs = l.procedure()?;
118    l.unresolved_statuses()?;
119    l.services.entries = l.entry_points()?;
120    l.services.class = l.class_definition()?;
121    l.services.function = l.function_definition()?;
122    let procedure_start = compiled.program.report_writer.procedure_start.min(compiled.program.paragraphs.len());
123    let (blocks, debug) = l.blocks.finish()?;
124    let program = lir::Program {
125        id,
126        options: lir::ProgramOptions {
127            options: compiled.options,
128            ssrange: compiled.ssrange,
129            cards: compiled.program.options.clone(),
130            collating: collating(&compiled.collating),
131            decimal_point_comma: compiled.program.environment.decimal_point_comma,
132            numval_currency: crate::machine::numval_currency(&compiled.program.environment.currency),
133            when_compiled: l.plans.function.iter().any(|f| f.func == lir::Func::WhenCompiled).then_some(compiled.when_compiled),
134        },
135        initial: compiled.program.initial,
136        recursive: compiled.program.recursive,
137        storage,
138        items,
139        paragraphs,
140        procedure_start: procedure_start as u32,
141        ranges: l.ranges,
142        blocks,
143        places: l.places,
144        exprs: l.exprs,
145        conds: l.conds,
146        consts: l.consts,
147        plans: l.plans,
148        services: l.services,
149        sql: l.sql,
150        abends: l.abends,
151        edits: edits(&compiled.layout)?,
152        symbols: l.symbols,
153        debug: lir::Debug { sources, positions: l.positions, ops: debug.ops, statements: debug.statements },
154    };
155    if cfg!(debug_assertions) {
156        verify(&program).map_err(LowerError::Invalid)?;
157    }
158    Ok(program)
159}
160
161/// The tables a program lowers into, each interned where equal entries may be shared.
162struct Lower<'c> {
163    c: &'c Compiled,
164    layout: &'c Layout,
165    program: &'c ast::Program,
166    page: &'static CodePage,
167    symbols: Vec<String>,
168    symbol_ids: HashMap<String, SymId>,
169    positions: Vec<Pos>,
170    position_ids: HashMap<(u16, u32, u32), DebugId>,
171    places: Vec<lir::Place>,
172    /// The layout item each place names, None for RETURN-CODE the program does not declare.
173    place_items: Vec<Option<usize>>,
174    place_ids: HashMap<String, PlaceId>,
175    exprs: Vec<lir::Expr>,
176    conds: Vec<lir::Cond>,
177    consts: Vec<lir::Const>,
178    const_ids: HashMap<String, ConstId>,
179    abends: Vec<lir::AbendText>,
180    abend_ids: HashMap<String, AbendId>,
181    plans: lir::Plans,
182    services: lir::Services,
183    /// Every EXEC SQL block's entry, by ordinal.
184    sql: Vec<lir::SqlEntry>,
185    ranges: Vec<lir::Range>,
186    range_ids: HashMap<(u32, u32, lir::RangeKind), RangeId>,
187    blocks: flow::Blocks,
188    temps: u16,
189    /// Each paragraph's entry block.
190    entries: Vec<BlockId>,
191    /// The block that starts statement k of paragraph p, after a separator period.
192    sentences: HashMap<(usize, usize), BlockId>,
193    /// The block that starts statement k of paragraph p, after an ENTRY statement.
194    entry_blocks: HashMap<(usize, usize), BlockId>,
195    /// The paragraphs an ALTER names.
196    altered: BTreeSet<usize>,
197    /// Whether an ALTER names a paragraph of an independent segment, which makes the segment
198    /// control reaches observable.
199    segments: bool,
200    /// Under the DEBUG option, whether a debugging section serves a paragraph.
201    debugging: bool,
202    /// The arithmetic of the expression being lowered, which its functions' argument expressions
203    /// take part in.
204    within: data::Within,
205}
206
207impl<'c> Lower<'c> {
208    fn new(c: &'c Compiled) -> Self {
209        Self {
210            c,
211            layout: &c.layout,
212            program: &c.program,
213            page: c.options.code_page(),
214            symbols: Vec::new(),
215            symbol_ids: HashMap::new(),
216            positions: Vec::new(),
217            position_ids: HashMap::new(),
218            places: Vec::new(),
219            place_items: Vec::new(),
220            place_ids: HashMap::new(),
221            exprs: Vec::new(),
222            conds: Vec::new(),
223            consts: Vec::new(),
224            const_ids: HashMap::new(),
225            abends: Vec::new(),
226            abend_ids: HashMap::new(),
227            plans: lir::Plans::default(),
228            services: lir::Services::default(),
229            sql: Vec::new(),
230            ranges: Vec::new(),
231            range_ids: HashMap::new(),
232            blocks: flow::Blocks::default(),
233            temps: 0,
234            entries: Vec::new(),
235            sentences: HashMap::new(),
236            entry_blocks: HashMap::new(),
237            altered: BTreeSet::new(),
238            segments: false,
239            debugging: !c.declaratives.triggers.is_empty(),
240            within: data::Within::Own,
241        }
242    }
243
244    fn sym(&mut self, text: &str) -> SymId {
245        if let Some(&id) = self.symbol_ids.get(text) {
246            return id;
247        }
248        let id = self.symbols.len() as SymId;
249        self.symbols.push(text.to_owned());
250        self.symbol_ids.insert(text.to_owned(), id);
251        id
252    }
253
254    fn at(&mut self, pos: Pos) -> DebugId {
255        let key = (pos.file, pos.line, pos.col);
256        if let Some(&id) = self.position_ids.get(&key) {
257            return id;
258        }
259        let id = self.positions.len() as DebugId;
260        self.positions.push(pos);
261        self.position_ids.insert(key, id);
262        id
263    }
264
265    /// An abend's text, with a position of its own only where no op gives one.
266    fn abend(&mut self, code: AbendCode, message: &str, pos: Option<Pos>) -> R<AbendId> {
267        let at = pos.map(|p| self.at(p));
268        let key = format!("{code:?}{at:?}{message}");
269        if let Some(&id) = self.abend_ids.get(&key) {
270            return Ok(id);
271        }
272        let text = lir::AbendText { code, message: self.sym(message), at };
273        let id = push(&mut self.abends, text, "abend messages")?;
274        self.abend_ids.insert(key, id);
275        Ok(id)
276    }
277
278    fn ironwork(&mut self, message: &str) -> R<AbendId> {
279        self.abend(AbendCode::Ironwork, message, None)
280    }
281
282    /// The slab and LOCAL-STORAGE as the walker's own VALUE initialization leaves them, run once
283    /// in a run unit of their own, with what it reported and any abend.
284    fn storage(&mut self) -> R<lir::Storage> {
285        let layout = self.layout;
286        let (size, local) = (layout.size as usize, layout.local_size as usize);
287        let (mut out, mut err) = (Vec::new(), Vec::new());
288        let (image, local_image, abend) = {
289            let mut unit = RunUnit::new(Library::default(), crate::files::Dds::default(), None, Clock::Fixed(0, 0), &mut out, &mut err);
290            let me = unit.add(None, self.program, size);
291            let abend = Machine::unbound(self.c, me, &mut unit).err();
292            let base = unit.programs[me].base;
293            let image = unit.mem[base..base + size].to_vec();
294            let local_image = if local > 0 { unit.mem[unit.mem.len() - local..].to_vec() } else { Vec::new() };
295            (image, local_image, abend)
296        };
297        let init_reports = String::from_utf8_lossy(&err).lines().map(|l| self.sym(l)).collect();
298        let init_abend = match abend {
299            Some(a) => Some(self.abend(a.code.clone(), &a.message, Some(a.pos))?),
300            None => None,
301        };
302        let root = |name: &str| layout.linkage_roots.iter().position(|&i| layout.items[i].name.as_deref() == Some(name));
303        let mut using = Vec::new();
304        // BY VALUE or BY REFERENCE is the caller's to honour, for the walker as for the VM.
305        for ast::Param { by_value: _, name } in &self.program.using {
306            match root(name).map(u16::try_from) {
307                Some(Ok(ordinal)) => using.push(ordinal),
308                Some(Err(_)) => return Err(LowerError::Exceeds("LINKAGE records", Pos::default())),
309                None => return unsupported("PROCEDURE DIVISION USING an item that is not a LINKAGE record", Pos::default()),
310            }
311        }
312        let returning = match &self.program.returning {
313            None => None,
314            Some(name) => match root(name).map(u16::try_from) {
315                Some(Ok(ordinal)) => Some(ordinal),
316                Some(Err(_)) => return Err(LowerError::Exceeds("LINKAGE records", Pos::default())),
317                None => return unsupported("RETURNING an item that is not a LINKAGE record", Pos::default()),
318            },
319        };
320        Ok(lir::Storage {
321            size: layout.size,
322            image,
323            local_image,
324            init_reports,
325            init_abend,
326            linkage: layout.linkage_roots.iter().map(|&i| layout.items[i].size).collect(),
327            using,
328            returning,
329            file_areas: layout.file_areas.clone(),
330            parmcheck: layout.parmcheck,
331        })
332    }
333
334    /// The layout's items for `dump`, with DEPENDING ON objects and keys as item indices.
335    fn items(&mut self) -> R<Vec<lir::Item>> {
336        let layout = self.layout;
337        let mut items = Vec::with_capacity(layout.items.len());
338        for item in &layout.items {
339            let item_of = |r: &ast::Ref| match layout.resolve(&r.name, &r.qualifiers, r.pos) {
340                Ok(Resolved::Item(i)) => Ok(i as u32),
341                _ => unsupported("an OCCURS DEPENDING ON or KEY that names no data item", r.pos),
342            };
343            let depending_on = item.depending_on.as_ref().map(item_of).transpose()?;
344            let keys = item.keys.iter().map(|(ascending, r)| item_of(r).map(|i| (*ascending, i))).collect::<R<_>>()?;
345            items.push(lir::Item {
346                name: item.name.as_deref().map(|n| self.sym(n)),
347                level: item.level,
348                parent: item.parent.map(|p| p as u32),
349                offset: item.offset,
350                size: item.size,
351                occurs: item.occurs,
352                dims: item.dims.clone(),
353                kind: item.kind,
354                local: item.local,
355                linkage: item.linkage,
356                redefines: item.redefines.as_deref().map(|n| self.sym(n)),
357                depending_on,
358                keys,
359                at: self.at(item.pos),
360            });
361        }
362        Ok(items)
363    }
364}
365
366/// The program's sequence, from what `collating::Sequence` exposes: each byte's position, the
367/// character FUNCTION CHAR gives for each position, and HIGH-VALUE and LOW-VALUE.
368fn collating(sequence: &crate::collating::Sequence) -> lir::Collating {
369    if sequence.is_native() {
370        return lir::Collating::Native;
371    }
372    let characters = (1..=sequence.count() as i64).filter_map(|k| sequence.character(k)).collect();
373    lir::Collating::Sequence(lir::Sequence {
374        positions: Box::new(sequence.positions()),
375        characters,
376        high_value: sequence.high_value,
377        low_value: sequence.low_value,
378    })
379}
380
381/// Each edited PICTURE with the currency sign value it shows.
382fn edits(layout: &Layout) -> R<Vec<lir::Edit>> {
383    if layout.edits.len() != layout.currencies.len() {
384        return Err(LowerError::Invalid(format!("{} edited PICTUREs with {} currency values", layout.edits.len(), layout.currencies.len())));
385    }
386    Ok(layout.edits.iter().zip(&layout.currencies).map(|(syms, currency)| lir::Edit { syms: syms.clone(), currency: currency.clone() }).collect())
387}
388
389/// Whether the place cannot abend when evaluated: a slab, LOCAL-STORAGE or RETURN-CODE base and a
390/// constant offset and length.
391fn is_static(place: &lir::Place) -> bool {
392    matches!(place.base, lir::Base::Program | lir::Base::Local | lir::Base::ReturnCode) && place.moved.is_empty() && place.subscripts.is_empty() && place.odo.is_empty() && place.refmod.is_none()
393}
ironwork_exec/lower/mod.rs

ironwork_exec/lower/
mod.rs
