rucc_ir/opcode.rs
1//! The instruction set.
2//!
3//! Design: `spec/08-ir.md` section 8.3.
4//!
5//! The set is small enough to enumerate and it is closed. Adding an opcode is a spec change,
6//! because the verifier, the printer, the parser, the rewrite rules and the lowering all have
7//! to learn it, and an opcode that only half of them know about is a silent miscompilation
8//! waiting for the right input.
9//!
10//! Two things are deliberately absent. There is no `getelementptr`: pointer arithmetic is
11//! [`Opcode::PtrAdd`] over a byte offset the frontend computed, because C never needs the
12//! multi-index form and its absence removes a well known source of complexity. And there is no
13//! `phi`: values arriving at a block are the block's parameters, passed by the branch, so
14//! there is no operand list positionally tied to a predecessor list kept somewhere else.
15
16use std::fmt;
17
18/// One instruction of the IR.
19///
20/// The names are the textual form exactly, so [`Opcode::name`] and [`Opcode::from_name`] are
21/// what the printer and the parser use, and neither carries a table of its own that could
22/// drift from this one.
23///
24/// The enum is not `non_exhaustive`, deliberately. The set is closed, so a pass that matches
25/// on every opcode should stop compiling when one is added rather than fall into a wildcard
26/// arm that quietly does the wrong thing.
27#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
28pub enum Opcode {
29 // Constants. A constant is an instruction rather than an operand kind, so that every
30 // operand is a value and every value has one definition, which is what makes the
31 // dominance check in the verifier a single rule rather than a rule with exceptions.
32 /// An integer constant, `iconst.i32 7`.
33 IConst,
34 /// A floating point constant, `fconst.f64 0x1.8p+1`.
35 FConst,
36 /// A vector constant with every lane the same, `splat.i8x16 0`.
37 Splat,
38 /// The address of a global or a function, `global_addr @counter`.
39 GlobalAddr,
40 /// The address of a block in this function, `block_addr block3`.
41 ///
42 /// The one instruction that names a block without being a branch, which is what GNU's
43 /// `&&label` is. Where it goes is [`Opcode::IndirectBr`], and the two are only useful
44 /// together: an address on its own is a number that nothing can do anything with.
45 BlockAddr,
46
47 // Arithmetic.
48 /// Integer addition.
49 Add,
50 /// Integer subtraction.
51 Sub,
52 /// Integer multiplication.
53 Mul,
54 /// Signed division.
55 SDiv,
56 /// Unsigned division.
57 UDiv,
58 /// Signed remainder, with the sign of the dividend.
59 SRem,
60 /// Unsigned remainder.
61 URem,
62 /// Bitwise and.
63 And,
64 /// Bitwise or.
65 Or,
66 /// Bitwise exclusive or.
67 Xor,
68 /// Shift left.
69 Shl,
70 /// Logical shift right, shifting in zeroes.
71 LShr,
72 /// Arithmetic shift right, shifting in the sign bit.
73 AShr,
74 /// Floating point addition.
75 FAdd,
76 /// Floating point subtraction.
77 FSub,
78 /// Floating point multiplication.
79 FMul,
80 /// Floating point division.
81 FDiv,
82 /// Floating point remainder.
83 FRem,
84 /// Floating point negation, which flips the sign bit and is not `0 - x`.
85 FNeg,
86 /// Fused multiply-add, rounded once.
87 Fma,
88
89 // Comparison.
90 /// Integer comparison, producing `i1` or a vector of `i1`.
91 ICmp,
92 /// Floating point comparison, producing `i1` or a vector of `i1`.
93 FCmp,
94
95 // Selection.
96 /// One of two values, chosen by a bit. `select c, a, b` is `a` when `c` is one.
97 ///
98 /// This is what control flow becomes when it stops being control flow.
99 /// `spec/optimizer/22-phiopt-and-if-conversion.md` section 22.2 makes it the lowering target
100 /// for a diamond whose two arms compute a value, and the reason it is an opcode rather than a
101 /// pattern is that it is the form the rule set is written against: `select(c, a, a) -> a` and
102 /// `select(c, 1, 0) -> zext(c)` are ordinary rules once the shape has a name.
103 ///
104 /// Both arms are evaluated, which is the whole point and also the whole danger. Whatever
105 /// produces one of these owes the argument that evaluating the arm that is not chosen is
106 /// harmless, and section 22.6 is the list of ways that argument goes wrong.
107 Select,
108
109 // Conversion.
110 /// Narrows an integer, discarding the high bits.
111 Trunc,
112 /// Widens an integer, copying the sign bit.
113 SExt,
114 /// Widens an integer, filling with zeroes.
115 ZExt,
116 /// Narrows a floating point value.
117 FPTrunc,
118 /// Widens a floating point value.
119 FPExt,
120 /// Floating point to signed integer.
121 FPToSI,
122 /// Floating point to unsigned integer.
123 FPToUI,
124 /// Signed integer to floating point.
125 SIToFP,
126 /// Unsigned integer to floating point.
127 UIToFP,
128 /// An address to an integer of the same width.
129 PtrToInt,
130 /// An integer to an address.
131 IntToPtr,
132 /// A reinterpretation of the same bits at the same width.
133 Bitcast,
134
135 // Memory.
136 /// Memory as the function found it, which is where a memory SSA chain starts.
137 ///
138 /// It produces one `mem` and takes nothing, and it belongs at the top of the entry block.
139 /// GCC calls the same thing the default definition of `.MEM` and LLVM calls it
140 /// `liveOnEntry`. It exists as an instruction rather than as a parameter of the entry block
141 /// because the entry block's parameters are the function's parameters and the verifier
142 /// checks them against the signature, and memory is not an argument anybody passed.
143 MemEntry,
144 /// A stack slot. In the entry block, or marked dynamic for a variable length array.
145 Alloca,
146 /// A read.
147 Load,
148 /// A write, producing no value.
149 Store,
150 /// Address arithmetic: an address and a byte offset.
151 PtrAdd,
152 /// A copy of a known size between addresses that do not overlap.
153 Memcpy,
154 /// A copy of a known size between addresses that may overlap.
155 Memmove,
156 /// A fill of a known size with one byte.
157 Memset,
158 /// An atomic read.
159 AtomicLoad,
160 /// An atomic write.
161 AtomicStore,
162 /// An atomic read-modify-write, carrying which operation in [`RmwOp`](crate::RmwOp).
163 AtomicRmw,
164 /// An atomic compare and exchange, producing the old value and whether it succeeded.
165 Cmpxchg,
166 /// A memory barrier.
167 Fence,
168
169 // Memory safety. Design: `spec/safe-memory/06-instrumentation.md` section 6.2.2. None of
170 // these is emitted unless `-fsafety` asked for it, and a function compiled without it
171 // contains not one of them.
172 /// The capability of a pointer value, taken from the pointer's provenance.
173 CapOf,
174 /// The capability in the auxiliary slot beside a stored pointer, read back.
175 ///
176 /// A pointer written to memory and read again has to bring its capability with it, and where
177 /// the capability lives is document 05's question rather than this one's. What this says is
178 /// that a capability comes back from an address, which is enough for every pass above.
179 CapLoad,
180 /// The other half of [`Opcode::CapLoad`], writing one into the slot beside a pointer.
181 CapStore,
182 /// The capability that permits nothing, which is what a null pointer has.
183 CapNull,
184 /// A capability narrowed to a sub-object of what it covered.
185 ///
186 /// Only under `-fsafety-subobject`. Narrowing is what catches an overflow from one member of
187 /// a struct into the next, and it is separate because C code that walks off the end of a
188 /// member on purpose exists and a project has to be able to say so.
189 CapNarrow,
190 /// The capability for an address that arrived from outside, recovered from the planes.
191 CapRecover,
192 /// An access is within its capability's bounds, aligned, and permitted.
193 ///
194 /// The size and the alignment are the access's, and they are in the memory payload rather
195 /// than in operands because they are what the front end knew and not what the program
196 /// computed.
197 CheckBounds,
198 /// The capability's provenance is still live.
199 CheckLive,
200 /// The access agrees with the type plane, which is the effective type rule of C 6.5.
201 CheckType,
202 /// The bytes the access reads have been written.
203 CheckInit,
204 /// A pointer derived from another stays inside the capability the first one had.
205 ///
206 /// Three operands, because the answer is about the new pointer and the question is about
207 /// the old one's capability.
208 CheckDeriv,
209 /// The metadata this access is about to consult has not been changed under it.
210 CheckRace,
211 /// A storage instance begins here, over a range, with a class.
212 ///
213 /// Judgement J4. This is the `alloca` for an automatic instance and the allocator's report
214 /// for an allocated one, and the range is a pointer and a length in registers rather than a
215 /// payload, because the length of a variable length array is not known when the instruction
216 /// is written down.
217 MetaBegin,
218 /// A storage instance ends here, which is judgement J5.
219 ///
220 /// Every capability for it fails from this point on and keeps failing after the address is
221 /// handed out again, which is what makes the check a use after free check rather than a use
222 /// after reallocation one.
223 MetaEnd,
224 /// The effective type of a range is now this one.
225 MetaType,
226 /// The bytes of a range are now initialized.
227 MetaInit,
228 /// A range leaves the monitor's authority, or comes back, which is judgement J7.
229 MetaTransfer,
230 /// A declared exemption starts here, with the reason it was declared.
231 ///
232 /// Not an optimization hint. Everything between this and its `safe_region_end` is code the
233 /// monitor is told not to judge, so the reason it carries is a trust set entry, and
234 /// `spec/safe-memory/10-boundaries.md` section 10.2 counts them per build precisely so that
235 /// a reviewer can read what a binary's guarantee rests on.
236 SafeRegionBegin,
237 /// The end of the region the last `safe_region_begin` opened.
238 SafeRegionEnd,
239
240 // Control. Every one of these is a terminator.
241 /// An unconditional branch, `jump block1(%a, %b)`.
242 Jump,
243 /// A two-way branch on an `i1`.
244 BrIf,
245 /// A multi-way branch on an integer, with a default.
246 Switch,
247 /// A branch to an address, `indirect_br %0, block1, block2`.
248 ///
249 /// The targets are every block control can arrive at, which is what makes the edges of a
250 /// computed `goto` ordinary edges: nothing else in the compiler has to know that the
251 /// address decides which one it is. A target that is not listed is a branch that does not
252 /// happen, so a frontend that leaves one out has made a promise on the program's behalf.
253 IndirectBr,
254 /// A return, with the values the signature says.
255 Return,
256 /// A place control cannot reach, which the frontend emits after a `noreturn` call.
257 Unreachable,
258
259 // Calls.
260 /// A call to a named function.
261 Call,
262 /// A call through an address, carrying the signature it is called with.
263 CallIndirect,
264 /// A call in tail position that reuses the frame, which is a terminator.
265 TailCall,
266
267 // Intrinsics, which is the closed part. The open part is `TargetIntrinsic`.
268 /// Count leading zeroes.
269 Ctlz,
270 /// Count trailing zeroes.
271 Cttz,
272 /// Count set bits.
273 Ctpop,
274 /// Reverse the bytes.
275 Bswap,
276 /// Reverse the bits.
277 Bitreverse,
278 /// Signed addition, producing the result and whether it overflowed.
279 SAddOverflow,
280 /// Unsigned addition, producing the result and whether it overflowed.
281 UAddOverflow,
282 /// Signed subtraction, producing the result and whether it overflowed.
283 SSubOverflow,
284 /// Unsigned subtraction, producing the result and whether it overflowed.
285 USubOverflow,
286 /// Signed multiplication, producing the result and whether it overflowed.
287 SMulOverflow,
288 /// Unsigned multiplication, producing the result and whether it overflowed.
289 UMulOverflow,
290 /// `__builtin_expect`, which is the value with a hint attached.
291 Expect,
292 /// `__builtin_unreachable` as a hint on a path, distinct from the terminator.
293 UnreachableHint,
294 /// `__builtin_prefetch`.
295 Prefetch,
296 /// `__builtin_frame_address`.
297 FrameAddress,
298 /// `__builtin_return_address`.
299 ReturnAddress,
300 /// The start of a variable argument list.
301 VaStart,
302 /// One argument off a variable argument list, which moves the list on as it reads it. Two
303 /// of these on one list are two arguments and never one argument read twice, so whatever
304 /// decides which instructions may be folded together has to leave these alone.
305 VaArg,
306 /// One argument off a variable argument list, when that argument is an object rather than a
307 /// value, which is what a `struct` or a `union` read out of one is.
308 ///
309 /// It answers the address of the object rather than the object, because an aggregate is not
310 /// a value and there is nothing for one result to be. Where the object arrives in registers
311 /// there is no address until something makes one, so what this asks of a target is a place
312 /// to put the registers and the address of that place, which is the copy every psABI's own
313 /// description of the algorithm makes. It moves the list on for the reason [`Opcode::VaArg`]
314 /// does.
315 VaObject,
316 /// The end of a variable argument list.
317 VaEnd,
318 /// A copy of a variable argument list.
319 VaCopy,
320 /// The stack pointer, saved before a variable length array.
321 StackSave,
322 /// The stack pointer, restored after one.
323 StackRestore,
324 /// The marker a `setjmp` leaves, which pins everything live across it.
325 SetjmpMarker,
326 /// The marker a `longjmp` leaves.
327 LongjmpMarker,
328 /// A target-specific intrinsic, named rather than enumerated, for the vector builtins.
329 TargetIntrinsic,
330
331 /// Inline assembly. A terminator when it has labels, which is `asm goto`.
332 InlineAsm,
333}
334
335impl Opcode {
336 /// The textual form, which is also what the parser reads.
337 #[must_use]
338 pub const fn name(self) -> &'static str {
339 match self {
340 Self::IConst => "iconst",
341 Self::FConst => "fconst",
342 Self::Splat => "splat",
343 Self::GlobalAddr => "global_addr",
344 Self::BlockAddr => "block_addr",
345 Self::Add => "add",
346 Self::Sub => "sub",
347 Self::Mul => "mul",
348 Self::SDiv => "sdiv",
349 Self::UDiv => "udiv",
350 Self::SRem => "srem",
351 Self::URem => "urem",
352 Self::And => "and",
353 Self::Or => "or",
354 Self::Xor => "xor",
355 Self::Shl => "shl",
356 Self::LShr => "lshr",
357 Self::AShr => "ashr",
358 Self::FAdd => "fadd",
359 Self::FSub => "fsub",
360 Self::FMul => "fmul",
361 Self::FDiv => "fdiv",
362 Self::FRem => "frem",
363 Self::FNeg => "fneg",
364 Self::Fma => "fma",
365 Self::ICmp => "icmp",
366 Self::FCmp => "fcmp",
367 Self::Select => "select",
368 Self::Trunc => "trunc",
369 Self::SExt => "sext",
370 Self::ZExt => "zext",
371 Self::FPTrunc => "fptrunc",
372 Self::FPExt => "fpext",
373 Self::FPToSI => "fptosi",
374 Self::FPToUI => "fptoui",
375 Self::SIToFP => "sitofp",
376 Self::UIToFP => "uitofp",
377 Self::PtrToInt => "ptrtoint",
378 Self::IntToPtr => "inttoptr",
379 Self::Bitcast => "bitcast",
380 Self::MemEntry => "mem_entry",
381 Self::Alloca => "alloca",
382 Self::Load => "load",
383 Self::Store => "store",
384 Self::PtrAdd => "ptr_add",
385 Self::Memcpy => "memcpy",
386 Self::Memmove => "memmove",
387 Self::Memset => "memset",
388 Self::AtomicLoad => "atomic_load",
389 Self::AtomicStore => "atomic_store",
390 Self::AtomicRmw => "atomic_rmw",
391 Self::Cmpxchg => "cmpxchg",
392 Self::Fence => "fence",
393 Self::CapOf => "cap_of",
394 Self::CapLoad => "cap_load",
395 Self::CapStore => "cap_store",
396 Self::CapNull => "cap_null",
397 Self::CapNarrow => "cap_narrow",
398 Self::CapRecover => "cap_recover",
399 Self::CheckBounds => "check_bounds",
400 Self::CheckLive => "check_live",
401 Self::CheckType => "check_type",
402 Self::CheckInit => "check_init",
403 Self::CheckDeriv => "check_deriv",
404 Self::CheckRace => "check_race",
405 Self::MetaBegin => "meta_begin",
406 Self::MetaEnd => "meta_end",
407 Self::MetaType => "meta_type",
408 Self::MetaInit => "meta_init",
409 Self::MetaTransfer => "meta_transfer",
410 Self::SafeRegionBegin => "safe_region_begin",
411 Self::SafeRegionEnd => "safe_region_end",
412 Self::Jump => "jump",
413 Self::BrIf => "br_if",
414 Self::Switch => "switch",
415 Self::IndirectBr => "indirect_br",
416 Self::Return => "return",
417 Self::Unreachable => "unreachable",
418 Self::Call => "call",
419 Self::CallIndirect => "call_indirect",
420 Self::TailCall => "tail_call",
421 Self::Ctlz => "ctlz",
422 Self::Cttz => "cttz",
423 Self::Ctpop => "ctpop",
424 Self::Bswap => "bswap",
425 Self::Bitreverse => "bitreverse",
426 Self::SAddOverflow => "sadd_overflow",
427 Self::UAddOverflow => "uadd_overflow",
428 Self::SSubOverflow => "ssub_overflow",
429 Self::USubOverflow => "usub_overflow",
430 Self::SMulOverflow => "smul_overflow",
431 Self::UMulOverflow => "umul_overflow",
432 Self::Expect => "expect",
433 Self::UnreachableHint => "unreachable_hint",
434 Self::Prefetch => "prefetch",
435 Self::FrameAddress => "frame_address",
436 Self::ReturnAddress => "return_address",
437 Self::VaStart => "va_start",
438 Self::VaArg => "va_arg",
439 Self::VaObject => "va_object",
440 Self::VaEnd => "va_end",
441 Self::VaCopy => "va_copy",
442 Self::StackSave => "stacksave",
443 Self::StackRestore => "stackrestore",
444 Self::SetjmpMarker => "setjmp_marker",
445 Self::LongjmpMarker => "longjmp_marker",
446 Self::TargetIntrinsic => "target_intrinsic",
447 Self::InlineAsm => "inline_asm",
448 }
449 }
450
451 /// Every opcode, in the order they are declared.
452 ///
453 /// The parser walks this rather than holding a second table, because a second table is a
454 /// table that can disagree with the first one.
455 pub fn all() -> impl Iterator<Item = Self> {
456 ALL.iter().copied()
457 }
458
459 /// The opcode with that name, if there is one.
460 #[must_use]
461 pub fn from_name(name: &str) -> Option<Self> {
462 ALL.iter().copied().find(|op| op.name() == name)
463 }
464
465 /// Whether this ends a block.
466 ///
467 /// [`Opcode::InlineAsm`] is not here and is the one instruction whose answer depends on
468 /// the instruction rather than on the opcode: `asm goto` has successors and everything
469 /// else does not. Ask the instruction, not the opcode.
470 #[must_use]
471 pub const fn is_terminator(self) -> bool {
472 matches!(
473 self,
474 Self::Jump
475 | Self::BrIf
476 | Self::Switch
477 | Self::IndirectBr
478 | Self::Return
479 | Self::Unreachable
480 | Self::TailCall
481 )
482 }
483
484 /// Whether the operands can be swapped without changing the result.
485 ///
486 /// The floating point cases are commutative even under the strictest rounding, because
487 /// swapping the operands of an addition does not change which of them is a NaN, and the
488 /// sign of a NaN result is not something we promise anything about either way.
489 #[must_use]
490 pub const fn is_commutative(self) -> bool {
491 matches!(
492 self,
493 Self::Add
494 | Self::Mul
495 | Self::And
496 | Self::Or
497 | Self::Xor
498 | Self::FAdd
499 | Self::FMul
500 | Self::SAddOverflow
501 | Self::UAddOverflow
502 | Self::SMulOverflow
503 | Self::UMulOverflow
504 )
505 }
506
507 /// Whether this reads or writes memory, or has an effect the optimizer has to preserve.
508 ///
509 /// An instruction that answers no can be deleted when nothing uses its result, moved
510 /// across a call, and merged with another one computing the same thing. Everything else
511 /// has to be argued about individually, so the conservative answer is the true one here
512 /// and the list of exceptions is the part that is checked.
513 #[must_use]
514 pub const fn has_effects(self) -> bool {
515 !matches!(
516 self,
517 Self::IConst
518 | Self::FConst
519 | Self::Splat
520 | Self::GlobalAddr
521 | Self::BlockAddr
522 | Self::Add
523 | Self::Sub
524 | Self::Mul
525 | Self::SDiv
526 | Self::UDiv
527 | Self::SRem
528 | Self::URem
529 | Self::And
530 | Self::Or
531 | Self::Xor
532 | Self::Shl
533 | Self::LShr
534 | Self::AShr
535 | Self::FAdd
536 | Self::FSub
537 | Self::FMul
538 | Self::FDiv
539 | Self::FRem
540 | Self::FNeg
541 | Self::Fma
542 | Self::ICmp
543 | Self::FCmp
544 | Self::Select
545 | Self::Trunc
546 | Self::SExt
547 | Self::ZExt
548 | Self::FPTrunc
549 | Self::FPExt
550 | Self::FPToSI
551 | Self::FPToUI
552 | Self::SIToFP
553 | Self::UIToFP
554 | Self::PtrToInt
555 | Self::IntToPtr
556 | Self::Bitcast
557 | Self::PtrAdd
558 | Self::Ctlz
559 | Self::Cttz
560 | Self::Ctpop
561 | Self::Bswap
562 | Self::Bitreverse
563 | Self::SAddOverflow
564 | Self::UAddOverflow
565 | Self::SSubOverflow
566 | Self::USubOverflow
567 | Self::SMulOverflow
568 | Self::UMulOverflow
569 | Self::Expect
570 | Self::FrameAddress
571 | Self::ReturnAddress
572 | Self::MemEntry
573 // Three of the capability instructions are arithmetic on a pointer's
574 // provenance and touch nothing. The other three do: `cap_load` and
575 // `cap_store` are an access, and `cap_recover` reads the planes.
576 | Self::CapOf
577 | Self::CapNull
578 | Self::CapNarrow
579 )
580 }
581
582 /// Whether an instruction with this opcode touches memory.
583 ///
584 /// This is what decides whether it takes a memory operand once memory SSA is built, per
585 /// document 09 of `spec/optimizer`. It is written as the exceptions to touching memory
586 /// rather than as a list of what does, for the reason document 08.6 gives about the escape
587 /// analysis: an opcode added later has to end up on the conservative side by default, and a
588 /// list of what touches memory would silently leave a new one out.
589 ///
590 /// `mem_entry` answers no. It produces memory rather than touching it, which is the whole
591 /// of what it is for.
592 #[must_use]
593 pub const fn touches_memory(self) -> bool {
594 if !self.has_effects() {
595 return false;
596 }
597 !matches!(
598 self,
599 // Fresh storage nothing could have been reading, and the pointer that names it.
600 Self::Alloca
601 // The stack pointer, which is a register and not memory. Putting it back is a
602 // different matter and is below, because it takes storage away.
603 | Self::StackSave
604 // Control, which goes somewhere rather than touching anything. A tail call is
605 // not here, because it is a call.
606 | Self::Jump
607 | Self::BrIf
608 | Self::Switch
609 | Self::IndirectBr
610 | Self::Return
611 | Self::Unreachable
612 | Self::UnreachableHint
613 )
614 }
615
616 /// Whether an instruction with this opcode writes memory, and so produces a new version of
617 /// it rather than only reading the version it was given.
618 ///
619 /// Everything that touches memory writes it except the ones that plainly do not. A `fence`
620 /// writes nothing and is still a write here, because document 09.5 says an atomic or a
621 /// barrier is a definition nothing walks past, and giving it one is how that is expressed
622 /// in a representation whose only ordering is the memory chain.
623 ///
624 /// The checks read the planes and change nothing, which
625 /// `spec/safe-memory/06-instrumentation.md` section 6.2.4 states as the word `readonly`. A
626 /// check that trapped is a program that stopped and there is no version of memory after it
627 /// for anything to observe, so the trap costs nothing here. What it does cost is that a
628 /// check may not be moved across a plane write, and that is the memory chain saying so
629 /// rather than this.
630 #[must_use]
631 pub const fn writes_memory(self) -> bool {
632 self.touches_memory()
633 && !matches!(
634 self,
635 Self::Load
636 | Self::AtomicLoad
637 | Self::Prefetch
638 | Self::CapLoad
639 | Self::CapRecover
640 | Self::CheckBounds
641 | Self::CheckLive
642 | Self::CheckType
643 | Self::CheckInit
644 | Self::CheckDeriv
645 | Self::CheckRace
646 )
647 }
648
649 /// How many values this produces, for the opcodes where the count is fixed.
650 ///
651 /// `None` means the count comes from somewhere else: a call takes it from its signature,
652 /// and inline assembly takes it from its output constraints. A tail call is not one of
653 /// them, because whatever it returns goes straight out of the function and there is no
654 /// instruction after it to use anything.
655 #[must_use]
656 pub const fn results(self) -> Option<u8> {
657 match self {
658 Self::Call | Self::CallIndirect | Self::InlineAsm => None,
659 Self::Cmpxchg
660 | Self::SAddOverflow
661 | Self::UAddOverflow
662 | Self::SSubOverflow
663 | Self::USubOverflow
664 | Self::SMulOverflow
665 | Self::UMulOverflow => Some(2),
666 Self::Store
667 | Self::Memcpy
668 | Self::Memmove
669 | Self::Memset
670 | Self::AtomicStore
671 | Self::Fence
672 | Self::Prefetch
673 | Self::VaStart
674 | Self::VaEnd
675 | Self::VaCopy
676 | Self::StackRestore
677 | Self::UnreachableHint
678 | Self::SetjmpMarker
679 | Self::LongjmpMarker
680 | Self::CapStore
681 | Self::CheckBounds
682 | Self::CheckLive
683 | Self::CheckType
684 | Self::CheckInit
685 | Self::CheckDeriv
686 | Self::CheckRace
687 | Self::MetaBegin
688 | Self::MetaEnd
689 | Self::MetaType
690 | Self::MetaInit
691 | Self::MetaTransfer
692 | Self::SafeRegionBegin
693 | Self::SafeRegionEnd => Some(0),
694 _ if self.is_terminator() => Some(0),
695 _ => Some(1),
696 }
697 }
698
699 /// Whether an instruction with this opcode produces a capability.
700 ///
701 /// Five of the six `cap` instructions, `cap_store` being the one that consumes one instead.
702 /// The reason this is a question about the opcode rather than about the
703 /// result type is that the verifier asks it the other way round: it walks the results looking
704 /// for a `cap` and needs to know whether the instruction under it was entitled to make one.
705 #[must_use]
706 pub const fn makes_capability(self) -> bool {
707 matches!(
708 self,
709 Self::CapOf | Self::CapLoad | Self::CapNull | Self::CapNarrow | Self::CapRecover
710 )
711 }
712
713 /// Which payload an instruction with this opcode carries.
714 ///
715 /// The printer reads the payload it finds and does not need this. The parser has only the
716 /// opcode when it reaches the operands, so this is where the two of them agree on what
717 /// comes after them. An instruction carrying a payload of some other kind prints as text
718 /// the parser cannot read back, which is why the verifier checks it against
719 /// [`Extra::kind`](crate::Extra::kind) rather than leaving it to be found later.
720 #[must_use]
721 pub const fn extra_kind(self) -> ExtraKind {
722 match self {
723 Self::IConst | Self::FConst | Self::Splat => ExtraKind::Imm,
724 Self::GlobalAddr | Self::TargetIntrinsic => ExtraKind::Symbol,
725 Self::ICmp => ExtraKind::IntPred,
726 Self::FCmp => ExtraKind::FloatPred,
727 Self::Alloca
728 | Self::Load
729 | Self::Store
730 | Self::Memcpy
731 | Self::Memmove
732 | Self::Memset
733 | Self::AtomicLoad
734 | Self::AtomicStore
735 | Self::Cmpxchg
736 // Three of the checks are about a run of bytes and the payload is where the size
737 // of that run is, along with the alignment `check_bounds` wants and the aliasing
738 // node `check_type` compares against. The other three ask a question about a
739 // pointer and not about a range, so they carry nothing.
740 | Self::CheckBounds
741 | Self::CheckType
742 | Self::CheckInit => ExtraKind::Mem,
743 // The plane writes. What each one needs beyond the range is different, and the range
744 // itself is operands, since the length of a variable length array is a value.
745 Self::MetaBegin => ExtraKind::Class,
746 Self::MetaTransfer => ExtraKind::Owner,
747 Self::MetaType => ExtraKind::Node,
748 Self::SafeRegionBegin => ExtraKind::Reason,
749 Self::VaObject => ExtraKind::VaObject,
750 Self::AtomicRmw => ExtraKind::Rmw,
751 Self::Fence => ExtraKind::Order,
752 Self::Jump | Self::BrIf | Self::BlockAddr | Self::IndirectBr => ExtraKind::Targets,
753 Self::Switch => ExtraKind::Switch,
754 Self::Call | Self::CallIndirect | Self::TailCall => ExtraKind::Call,
755 Self::InlineAsm => ExtraKind::Asm,
756 _ => ExtraKind::None,
757 }
758 }
759}
760
761/// Which of [`Extra`](crate::Extra)'s shapes an instruction carries.
762///
763/// The same list of names, without any of the payloads, so that a question about an opcode can
764/// be answered without an instruction to look at.
765#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
766pub enum ExtraKind {
767 /// Nothing.
768 None,
769 /// A constant.
770 Imm,
771 /// A name.
772 Symbol,
773 /// An integer comparison predicate.
774 IntPred,
775 /// A floating point comparison predicate.
776 FloatPred,
777 /// An access.
778 Mem,
779 /// An atomic read-modify-write.
780 Rmw,
781 /// A barrier's ordering.
782 Order,
783 /// Branch targets.
784 Targets,
785 /// A call.
786 Call,
787 /// A `switch`.
788 Switch,
789 /// Inline assembly.
790 Asm,
791 /// An object read off a variable argument list.
792 VaObject,
793 /// What kind of storage an instance is.
794 Class,
795 /// Who a range of memory went to.
796 Owner,
797 /// A metadata node.
798 Node,
799 /// Why a declared exemption is there.
800 Reason,
801}
802
803impl ExtraKind {
804 /// What it is, in words, for a message that names two of them and has to read as English.
805 #[must_use]
806 pub const fn name(self) -> &'static str {
807 match self {
808 Self::None => "nothing",
809 Self::Imm => "a constant",
810 Self::Symbol => "a name",
811 Self::IntPred => "an integer comparison",
812 Self::FloatPred => "a floating point comparison",
813 Self::Mem => "an access",
814 Self::Rmw => "a read-modify-write",
815 Self::Order => "an ordering",
816 Self::Targets => "branch targets",
817 Self::Call => "a call",
818 Self::Switch => "a switch",
819 Self::Asm => "inline assembly",
820 Self::VaObject => "an object off a variable argument list",
821 Self::Class => "a storage class",
822 Self::Owner => "an owner",
823 Self::Node => "a metadata node",
824 Self::Reason => "a reason",
825 }
826 }
827}
828
829impl fmt::Display for Opcode {
830 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
831 f.write_str(self.name())
832 }
833}
834
835/// Every opcode, which is what [`Opcode::all`] hands out.
836///
837/// This is written out rather than derived, and the test below is what keeps it complete: it
838/// checks the count against [`Opcode::InlineAsm`], the last variant, so a new opcode that is
839/// not added here fails the build rather than going quietly missing from the parser.
840static ALL: &[Opcode] = &[
841 Opcode::IConst,
842 Opcode::FConst,
843 Opcode::Splat,
844 Opcode::GlobalAddr,
845 Opcode::BlockAddr,
846 Opcode::Add,
847 Opcode::Sub,
848 Opcode::Mul,
849 Opcode::SDiv,
850 Opcode::UDiv,
851 Opcode::SRem,
852 Opcode::URem,
853 Opcode::And,
854 Opcode::Or,
855 Opcode::Xor,
856 Opcode::Shl,
857 Opcode::LShr,
858 Opcode::AShr,
859 Opcode::FAdd,
860 Opcode::FSub,
861 Opcode::FMul,
862 Opcode::FDiv,
863 Opcode::FRem,
864 Opcode::FNeg,
865 Opcode::Fma,
866 Opcode::ICmp,
867 Opcode::FCmp,
868 Opcode::Select,
869 Opcode::Trunc,
870 Opcode::SExt,
871 Opcode::ZExt,
872 Opcode::FPTrunc,
873 Opcode::FPExt,
874 Opcode::FPToSI,
875 Opcode::FPToUI,
876 Opcode::SIToFP,
877 Opcode::UIToFP,
878 Opcode::PtrToInt,
879 Opcode::IntToPtr,
880 Opcode::Bitcast,
881 Opcode::MemEntry,
882 Opcode::Alloca,
883 Opcode::Load,
884 Opcode::Store,
885 Opcode::PtrAdd,
886 Opcode::Memcpy,
887 Opcode::Memmove,
888 Opcode::Memset,
889 Opcode::AtomicLoad,
890 Opcode::AtomicStore,
891 Opcode::AtomicRmw,
892 Opcode::Cmpxchg,
893 Opcode::Fence,
894 Opcode::CapOf,
895 Opcode::CapLoad,
896 Opcode::CapStore,
897 Opcode::CapNull,
898 Opcode::CapNarrow,
899 Opcode::CapRecover,
900 Opcode::CheckBounds,
901 Opcode::CheckLive,
902 Opcode::CheckType,
903 Opcode::CheckInit,
904 Opcode::CheckDeriv,
905 Opcode::CheckRace,
906 Opcode::MetaBegin,
907 Opcode::MetaEnd,
908 Opcode::MetaType,
909 Opcode::MetaInit,
910 Opcode::MetaTransfer,
911 Opcode::SafeRegionBegin,
912 Opcode::SafeRegionEnd,
913 Opcode::Jump,
914 Opcode::BrIf,
915 Opcode::Switch,
916 Opcode::IndirectBr,
917 Opcode::Return,
918 Opcode::Unreachable,
919 Opcode::Call,
920 Opcode::CallIndirect,
921 Opcode::TailCall,
922 Opcode::Ctlz,
923 Opcode::Cttz,
924 Opcode::Ctpop,
925 Opcode::Bswap,
926 Opcode::Bitreverse,
927 Opcode::SAddOverflow,
928 Opcode::UAddOverflow,
929 Opcode::SSubOverflow,
930 Opcode::USubOverflow,
931 Opcode::SMulOverflow,
932 Opcode::UMulOverflow,
933 Opcode::Expect,
934 Opcode::UnreachableHint,
935 Opcode::Prefetch,
936 Opcode::FrameAddress,
937 Opcode::ReturnAddress,
938 Opcode::VaStart,
939 Opcode::VaArg,
940 Opcode::VaObject,
941 Opcode::VaEnd,
942 Opcode::VaCopy,
943 Opcode::StackSave,
944 Opcode::StackRestore,
945 Opcode::SetjmpMarker,
946 Opcode::LongjmpMarker,
947 Opcode::TargetIntrinsic,
948 Opcode::InlineAsm,
949];
950
951/// The ten integer comparisons.
952///
953/// Signedness is on the predicate rather than on the type, for the same reason it is on
954/// `sdiv` and `udiv`: the type space is halved and the operation says what it means.
955#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
956pub enum IntPred {
957 /// Equal.
958 Eq,
959 /// Not equal.
960 Ne,
961 /// Signed less than.
962 Slt,
963 /// Signed less than or equal.
964 Sle,
965 /// Signed greater than.
966 Sgt,
967 /// Signed greater than or equal.
968 Sge,
969 /// Unsigned less than.
970 Ult,
971 /// Unsigned less than or equal.
972 Ule,
973 /// Unsigned greater than.
974 Ugt,
975 /// Unsigned greater than or equal.
976 Uge,
977}
978
979impl IntPred {
980 /// The textual form.
981 #[must_use]
982 pub const fn name(self) -> &'static str {
983 match self {
984 Self::Eq => "eq",
985 Self::Ne => "ne",
986 Self::Slt => "slt",
987 Self::Sle => "sle",
988 Self::Sgt => "sgt",
989 Self::Sge => "sge",
990 Self::Ult => "ult",
991 Self::Ule => "ule",
992 Self::Ugt => "ugt",
993 Self::Uge => "uge",
994 }
995 }
996
997 /// The predicate with that name, if there is one.
998 #[must_use]
999 pub fn from_name(name: &str) -> Option<Self> {
1000 Self::all().find(|pred| pred.name() == name)
1001 }
1002
1003 /// Every predicate.
1004 pub fn all() -> impl Iterator<Item = Self> {
1005 [
1006 Self::Eq,
1007 Self::Ne,
1008 Self::Slt,
1009 Self::Sle,
1010 Self::Sgt,
1011 Self::Sge,
1012 Self::Ult,
1013 Self::Ule,
1014 Self::Ugt,
1015 Self::Uge,
1016 ]
1017 .into_iter()
1018 }
1019
1020 /// The predicate that holds exactly when this one does not.
1021 #[must_use]
1022 pub const fn inverse(self) -> Self {
1023 match self {
1024 Self::Eq => Self::Ne,
1025 Self::Ne => Self::Eq,
1026 Self::Slt => Self::Sge,
1027 Self::Sge => Self::Slt,
1028 Self::Sle => Self::Sgt,
1029 Self::Sgt => Self::Sle,
1030 Self::Ult => Self::Uge,
1031 Self::Uge => Self::Ult,
1032 Self::Ule => Self::Ugt,
1033 Self::Ugt => Self::Ule,
1034 }
1035 }
1036
1037 /// The predicate that holds when the operands are given the other way round.
1038 #[must_use]
1039 pub const fn swapped(self) -> Self {
1040 match self {
1041 Self::Eq => Self::Eq,
1042 Self::Ne => Self::Ne,
1043 Self::Slt => Self::Sgt,
1044 Self::Sgt => Self::Slt,
1045 Self::Sle => Self::Sge,
1046 Self::Sge => Self::Sle,
1047 Self::Ult => Self::Ugt,
1048 Self::Ugt => Self::Ult,
1049 Self::Ule => Self::Uge,
1050 Self::Uge => Self::Ule,
1051 }
1052 }
1053
1054 /// Whether this reads its operands as signed. Equality reads them as neither.
1055 #[must_use]
1056 pub const fn is_signed(self) -> bool {
1057 matches!(self, Self::Slt | Self::Sle | Self::Sgt | Self::Sge)
1058 }
1059}
1060
1061impl fmt::Display for IntPred {
1062 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1063 f.write_str(self.name())
1064 }
1065}
1066
1067/// The floating point comparisons, ordered and unordered.
1068///
1069/// An ordered predicate is false if either operand is a NaN, and an unordered one is true. C's
1070/// `<` is `olt` and C's `!=` is `une`, which is the whole of why both families are here.
1071#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1072pub enum FloatPred {
1073 /// Always false.
1074 False,
1075 /// Ordered and equal.
1076 Oeq,
1077 /// Ordered and greater than.
1078 Ogt,
1079 /// Ordered and greater than or equal.
1080 Oge,
1081 /// Ordered and less than.
1082 Olt,
1083 /// Ordered and less than or equal.
1084 Ole,
1085 /// Ordered and not equal.
1086 One,
1087 /// Ordered, which is to say neither operand is a NaN.
1088 Ord,
1089 /// Unordered, which is to say one of them is.
1090 Uno,
1091 /// Unordered or equal.
1092 Ueq,
1093 /// Unordered or greater than.
1094 Ugt,
1095 /// Unordered or greater than or equal.
1096 Uge,
1097 /// Unordered or less than.
1098 Ult,
1099 /// Unordered or less than or equal.
1100 Ule,
1101 /// Unordered or not equal.
1102 Une,
1103 /// Always true.
1104 True,
1105}
1106
1107impl FloatPred {
1108 /// The textual form.
1109 #[must_use]
1110 pub const fn name(self) -> &'static str {
1111 match self {
1112 Self::False => "false",
1113 Self::Oeq => "oeq",
1114 Self::Ogt => "ogt",
1115 Self::Oge => "oge",
1116 Self::Olt => "olt",
1117 Self::Ole => "ole",
1118 Self::One => "one",
1119 Self::Ord => "ord",
1120 Self::Uno => "uno",
1121 Self::Ueq => "ueq",
1122 Self::Ugt => "ugt",
1123 Self::Uge => "uge",
1124 Self::Ult => "ult",
1125 Self::Ule => "ule",
1126 Self::Une => "une",
1127 Self::True => "true",
1128 }
1129 }
1130
1131 /// The predicate with that name, if there is one.
1132 #[must_use]
1133 pub fn from_name(name: &str) -> Option<Self> {
1134 Self::all().find(|pred| pred.name() == name)
1135 }
1136
1137 /// Every predicate.
1138 pub fn all() -> impl Iterator<Item = Self> {
1139 [
1140 Self::False,
1141 Self::Oeq,
1142 Self::Ogt,
1143 Self::Oge,
1144 Self::Olt,
1145 Self::Ole,
1146 Self::One,
1147 Self::Ord,
1148 Self::Uno,
1149 Self::Ueq,
1150 Self::Ugt,
1151 Self::Uge,
1152 Self::Ult,
1153 Self::Ule,
1154 Self::Une,
1155 Self::True,
1156 ]
1157 .into_iter()
1158 }
1159
1160 /// The predicate that holds exactly when this one does not.
1161 #[must_use]
1162 pub const fn inverse(self) -> Self {
1163 match self {
1164 Self::False => Self::True,
1165 Self::Oeq => Self::Une,
1166 Self::Ogt => Self::Ule,
1167 Self::Oge => Self::Ult,
1168 Self::Olt => Self::Uge,
1169 Self::Ole => Self::Ugt,
1170 Self::One => Self::Ueq,
1171 Self::Ord => Self::Uno,
1172 Self::Uno => Self::Ord,
1173 Self::Ueq => Self::One,
1174 Self::Ugt => Self::Ole,
1175 Self::Uge => Self::Olt,
1176 Self::Ult => Self::Oge,
1177 Self::Ule => Self::Ogt,
1178 Self::Une => Self::Oeq,
1179 Self::True => Self::False,
1180 }
1181 }
1182
1183 /// The predicate that holds when the operands are given the other way round.
1184 #[must_use]
1185 pub const fn swapped(self) -> Self {
1186 match self {
1187 Self::Ogt => Self::Olt,
1188 Self::Olt => Self::Ogt,
1189 Self::Oge => Self::Ole,
1190 Self::Ole => Self::Oge,
1191 Self::Ugt => Self::Ult,
1192 Self::Ult => Self::Ugt,
1193 Self::Uge => Self::Ule,
1194 Self::Ule => Self::Uge,
1195 same => same,
1196 }
1197 }
1198
1199 /// Whether this is false when either operand is a NaN.
1200 ///
1201 /// [`FloatPred::False`] and [`FloatPred::True`] are neither ordered nor unordered, since
1202 /// they do not look at their operands at all, and both answer no here.
1203 #[must_use]
1204 pub const fn is_ordered(self) -> bool {
1205 matches!(
1206 self,
1207 Self::Oeq | Self::Ogt | Self::Oge | Self::Olt | Self::Ole | Self::One | Self::Ord
1208 )
1209 }
1210}
1211
1212impl fmt::Display for FloatPred {
1213 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1214 f.write_str(self.name())
1215 }
1216}
1217
1218#[cfg(test)]
1219mod tests {
1220 use super::*;
1221
1222 #[test]
1223 fn every_opcode_is_in_the_table() {
1224 // `InlineAsm` is the last variant, so its discriminant plus one is how many there are.
1225 // A new opcode declared after it moves this number, and a new opcode declared before
1226 // it and not added to `ALL` moves the length, so either mistake fails here.
1227 assert_eq!(ALL.len(), Opcode::InlineAsm as usize + 1);
1228 for (position, &op) in ALL.iter().enumerate() {
1229 assert_eq!(op as usize, position, "{op} is out of order in ALL");
1230 }
1231 }
1232
1233 #[test]
1234 fn every_opcode_name_is_one_word_the_reader_can_take() {
1235 // The textual form keeps the dot for the type suffix and the flags, so an opcode with a
1236 // dot in it reads back as a shorter opcode with a suffix that is not a type. The safety
1237 // instructions are spelled `cap_of` and not `cap.of` for this reason, and the
1238 // specification says so at `spec/safe-memory/06-instrumentation.md` section 6.2.2.
1239 for opcode in Opcode::all() {
1240 let name = opcode.name();
1241 assert!(!name.is_empty(), "an opcode with no name");
1242 assert!(
1243 name.bytes().all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'_'),
1244 "{name} is not one word"
1245 );
1246 }
1247 }
1248
1249 #[test]
1250 fn every_opcode_has_its_own_name_and_finds_it_again() {
1251 let mut names: Vec<&str> = Opcode::all().map(Opcode::name).collect();
1252 let total = names.len();
1253 names.sort_unstable();
1254 names.dedup();
1255 assert_eq!(names.len(), total, "two opcodes share a name");
1256 for op in Opcode::all() {
1257 assert_eq!(Opcode::from_name(op.name()), Some(op));
1258 }
1259 assert_eq!(Opcode::from_name("phi"), None);
1260 assert_eq!(Opcode::from_name("getelementptr"), None);
1261 assert_eq!(Opcode::from_name(""), None);
1262 }
1263
1264 #[test]
1265 fn the_terminators_are_the_ones_control_leaves_by() {
1266 let terminators: Vec<&str> =
1267 Opcode::all().filter(|op| op.is_terminator()).map(Opcode::name).collect();
1268 assert_eq!(
1269 terminators,
1270 ["jump", "br_if", "switch", "indirect_br", "return", "unreachable", "tail_call"]
1271 );
1272 }
1273
1274 #[test]
1275 fn a_terminator_produces_nothing() {
1276 for op in Opcode::all().filter(|op| op.is_terminator()) {
1277 assert_eq!(op.results(), Some(0), "{op}");
1278 }
1279 }
1280
1281 #[test]
1282 fn the_pair_producing_opcodes_are_the_ones_with_a_flag_beside_the_value() {
1283 let pairs: Vec<&str> =
1284 Opcode::all().filter(|op| op.results() == Some(2)).map(Opcode::name).collect();
1285 assert_eq!(
1286 pairs,
1287 [
1288 "cmpxchg",
1289 "sadd_overflow",
1290 "uadd_overflow",
1291 "ssub_overflow",
1292 "usub_overflow",
1293 "smul_overflow",
1294 "umul_overflow"
1295 ]
1296 );
1297 }
1298
1299 #[test]
1300 fn the_capability_instructions_are_the_ones_that_make_a_capability() {
1301 let makers: Vec<Opcode> = Opcode::all().filter(|op| op.makes_capability()).collect();
1302 assert_eq!(
1303 makers,
1304 vec![
1305 Opcode::CapOf,
1306 Opcode::CapLoad,
1307 Opcode::CapNull,
1308 Opcode::CapNarrow,
1309 Opcode::CapRecover
1310 ]
1311 );
1312 // The sixth is the one that writes a capability rather than making one, so it produces
1313 // nothing at all and is not on the list.
1314 assert!(!Opcode::CapStore.makes_capability());
1315 assert_eq!(Opcode::CapStore.results(), Some(0));
1316 for opcode in makers {
1317 assert_eq!(opcode.results(), Some(1), "{}", opcode.name());
1318 }
1319 }
1320
1321 #[test]
1322 fn a_check_reads_the_planes_and_writes_nothing() {
1323 let checks = [
1324 Opcode::CheckBounds,
1325 Opcode::CheckLive,
1326 Opcode::CheckType,
1327 Opcode::CheckInit,
1328 Opcode::CheckDeriv,
1329 Opcode::CheckRace,
1330 ];
1331 for opcode in checks {
1332 let name = opcode.name();
1333 // It traps, so it stays where it was put and nothing deletes it for having no
1334 // result. It reads a plane, so it takes a memory operand. It writes nothing, so
1335 // the access after it reads the version the check was given.
1336 assert!(opcode.has_effects(), "{name}");
1337 assert!(opcode.touches_memory(), "{name}");
1338 assert!(!opcode.writes_memory(), "{name}");
1339 assert_eq!(opcode.results(), Some(0), "{name}");
1340 }
1341 }
1342
1343 #[test]
1344 fn the_capability_instructions_that_touch_memory_are_the_three_that_have_to() {
1345 // `cap_load` and `cap_store` are an access to the slot beside a pointer and
1346 // `cap_recover` reads the planes. The other three are arithmetic on a provenance the
1347 // program already had, so the optimizer may treat them as it treats `ptr_add`.
1348 assert!(!Opcode::CapOf.has_effects());
1349 assert!(!Opcode::CapNull.has_effects());
1350 assert!(!Opcode::CapNarrow.has_effects());
1351 assert!(Opcode::CapLoad.touches_memory() && !Opcode::CapLoad.writes_memory());
1352 assert!(Opcode::CapRecover.touches_memory() && !Opcode::CapRecover.writes_memory());
1353 assert!(Opcode::CapStore.writes_memory());
1354 }
1355
1356 #[test]
1357 fn memory_has_effects_and_arithmetic_does_not() {
1358 for op in [Opcode::Load, Opcode::Store, Opcode::Call, Opcode::Alloca, Opcode::Fence] {
1359 assert!(op.has_effects(), "{op}");
1360 }
1361 for op in [Opcode::Add, Opcode::FDiv, Opcode::ICmp, Opcode::PtrAdd, Opcode::IConst] {
1362 assert!(!op.has_effects(), "{op}");
1363 }
1364 }
1365
1366 #[test]
1367 fn commuting_is_only_claimed_where_it_holds() {
1368 assert!(Opcode::Add.is_commutative());
1369 assert!(Opcode::FAdd.is_commutative());
1370 assert!(!Opcode::Sub.is_commutative());
1371 assert!(!Opcode::FDiv.is_commutative());
1372 assert!(!Opcode::Shl.is_commutative());
1373 }
1374
1375 #[test]
1376 fn an_integer_predicate_inverts_and_swaps_back_to_itself() {
1377 for pred in IntPred::all() {
1378 assert_eq!(pred.inverse().inverse(), pred);
1379 assert_eq!(pred.swapped().swapped(), pred);
1380 assert_eq!(IntPred::from_name(pred.name()), Some(pred));
1381 }
1382 assert_eq!(IntPred::Slt.inverse(), IntPred::Sge);
1383 assert_eq!(IntPred::Slt.swapped(), IntPred::Sgt);
1384 assert_eq!(IntPred::from_name("lt"), None);
1385 }
1386
1387 #[test]
1388 fn a_floating_predicate_inverts_across_the_ordered_line() {
1389 for pred in FloatPred::all() {
1390 assert_eq!(pred.inverse().inverse(), pred);
1391 assert_eq!(pred.swapped().swapped(), pred);
1392 assert_eq!(FloatPred::from_name(pred.name()), Some(pred));
1393 }
1394 // Inverting has to cross the line, because the negation of an ordered comparison is
1395 // true when an operand is a NaN. This is where `!(a < b)` stops being `a >= b`. The
1396 // two constants are outside it: neither of them looks at its operands.
1397 for pred in FloatPred::all().filter(|p| !matches!(p, FloatPred::False | FloatPred::True)) {
1398 assert_ne!(pred.is_ordered(), pred.inverse().is_ordered(), "{pred}");
1399 }
1400 assert_eq!(FloatPred::Olt.inverse(), FloatPred::Uge);
1401 assert_eq!(FloatPred::Olt.swapped(), FloatPred::Ogt);
1402 }
1403
1404 #[test]
1405 fn swapping_a_predicate_keeps_it_ordered_or_unordered() {
1406 for pred in FloatPred::all() {
1407 assert_eq!(pred.is_ordered(), pred.swapped().is_ordered(), "{pred}");
1408 }
1409 for pred in IntPred::all() {
1410 assert_eq!(pred.is_signed(), pred.swapped().is_signed(), "{pred}");
1411 }
1412 }
1413
1414 #[test]
1415 fn no_two_predicates_share_a_name_within_their_family() {
1416 for names in [
1417 IntPred::all().map(IntPred::name).collect::<Vec<_>>(),
1418 FloatPred::all().map(FloatPred::name).collect::<Vec<_>>(),
1419 ] {
1420 let total = names.len();
1421 let mut names = names;
1422 names.sort_unstable();
1423 names.dedup();
1424 assert_eq!(names.len(), total);
1425 }
1426 }
1427}