86 lines
3.2 KiB
Rust
86 lines
3.2 KiB
Rust
use crate::mir::function::MirFunction;
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use crate::mir::verification::utils;
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use crate::mir::verification_types::VerificationError;
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use crate::mir::{BasicBlockId, ValueId};
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use std::collections::{HashMap, HashSet};
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/// Verify CFG references and reachability
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pub fn check_control_flow(function: &MirFunction) -> Result<(), Vec<VerificationError>> {
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let mut errors = Vec::new();
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for (block_id, block) in &function.blocks {
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for successor in &block.successors {
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if !function.blocks.contains_key(successor) {
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errors.push(VerificationError::ControlFlowError {
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block: *block_id,
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reason: format!("References non-existent block {}", successor),
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});
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}
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}
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}
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// Unreachable blocks are allowed in MIR.
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// They are created intentionally by break/continue/return statements via
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// switch_to_unreachable_block_with_void() to continue SSA construction after
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// control flow terminators. This is standard practice (see LLVM's `unreachable`).
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// Dead code elimination pass (TODO) will remove them during optimization.
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if errors.is_empty() {
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Ok(())
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} else {
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Err(errors)
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}
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}
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/// Verify that merge blocks do not use predecessor-defined values directly (must go through Phi)
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pub fn check_merge_uses(function: &MirFunction) -> Result<(), Vec<VerificationError>> {
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if crate::config::env::verify_allow_no_phi() {
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return Ok(());
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}
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let mut errors = Vec::new();
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let preds = utils::compute_predecessors(function);
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let def_block = utils::compute_def_blocks(function);
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let dominators = utils::compute_dominators(function);
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let mut phi_dsts_in_block: HashMap<BasicBlockId, HashSet<ValueId>> = HashMap::new();
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for (bid, block) in &function.blocks {
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let set = phi_dsts_in_block.entry(*bid).or_default();
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for sp in block.all_spanned_instructions() {
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if let crate::mir::MirInstruction::Phi { dst, .. } = sp.inst {
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set.insert(*dst);
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}
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}
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}
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for (bid, block) in &function.blocks {
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let Some(pred_list) = preds.get(bid) else {
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continue;
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};
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if pred_list.len() < 2 {
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continue;
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}
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let phi_dsts = phi_dsts_in_block.get(bid);
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let doms_of_block = dominators.get(bid).unwrap();
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for sp in block.all_spanned_instructions() {
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if let crate::mir::MirInstruction::Phi { .. } = sp.inst {
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continue;
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}
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for used in sp.inst.used_values() {
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if let Some(&db) = def_block.get(&used) {
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if !doms_of_block.contains(&db) {
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let is_phi_dst = phi_dsts.map(|s| s.contains(&used)).unwrap_or(false);
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if !is_phi_dst {
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errors.push(VerificationError::MergeUsesPredecessorValue {
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value: used,
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merge_block: *bid,
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pred_block: db,
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});
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}
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}
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}
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}
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}
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}
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if errors.is_empty() {
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Ok(())
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} else {
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Err(errors)
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}
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}
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