T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Make DataFlowGraph::blocks public (#5740)

Browse Source 
Similar to when we exposed the DataFlowGraph::insts field through a restrictive newtype, expose DataFlowGraph::blocks through an interface that allows a restrictive set of operations. This field being public now allows us to avoid a rematch in ssa construction, and simplifies the implementation of adding a block argument to a block referenced by a br_table instruction.
This commit is contained in:
Trevor Elliott
2023-02-07 17:11:14 -08:00
committed by GitHub
parent f3b408d5e2
commit d71c9458dc
3 changed files with 72 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
cranelift/frontend/src/ssa.rs
View File

@@ -15,9 +15,7 @@ use cranelift_codegen::cursor::{Cursor, FuncCursor};
use cranelift_codegen::entity::{EntityList, EntitySet, ListPool, SecondaryMap};
use cranelift_codegen::ir::immediates::{Ieee32, Ieee64};
use cranelift_codegen::ir::types::{F32, F64, I128, I64};
use cranelift_codegen::ir::{
Block, Function, Inst, InstBuilder, InstructionData, JumpTableData, Type, Value,
};
use cranelift_codegen::ir::{Block, Function, Inst, InstBuilder, InstructionData, Type, Value};
use cranelift_codegen::packed_option::PackedOption;
/// Structure containing the data relevant the construction of SSA for a given function.
@@ -577,58 +575,41 @@ impl SSABuilder {
dest_block: Block,
val: Value,
) -> Option<(Block, Inst)> {
match &func.dfg.insts[branch] {
let dfg = &mut func.stencil.dfg;
match &mut dfg.insts[branch] {
// For a single destination appending a jump argument to the instruction
// is sufficient.
InstructionData::Jump { .. } => {
let dfg = &mut func.dfg;
for dest in dfg.insts[branch].branch_destination_mut() {
dest.append_argument(val, &mut dfg.value_lists);
}
InstructionData::Jump { destination, .. } => {
destination.append_argument(val, &mut dfg.value_lists);
None
}
InstructionData::Brif { .. } => {
let dfg = &mut func.dfg;
for block in dfg.insts[branch].branch_destination_mut() {
InstructionData::Brif { blocks, .. } => {
for block in blocks {
if block.block(&dfg.value_lists) == dest_block {
block.append_argument(val, &mut dfg.value_lists);
}
}
None
}
InstructionData::BranchTable { table: mut jt, .. } => {
InstructionData::BranchTable {
table: jt,
destination,
..
} => {
// In the case of a jump table, the situation is tricky because br_table doesn't
// support arguments. We have to split the critical edge.
let middle_block = func.dfg.make_block();
func.layout.append_block(middle_block);
let middle_block = dfg.blocks.add();
func.stencil.layout.append_block(middle_block);
let table = &func.jump_tables[jt];
let mut copied = JumpTableData::with_capacity(table.len());
let mut changed = false;
for &destination in table.iter() {
if destination == dest_block {
copied.push_entry(middle_block);
changed = true;
} else {
copied.push_entry(destination);
let table = &mut func.stencil.jump_tables[*jt];
for block in table.iter_mut() {
if *block == dest_block {
*block = middle_block;
}
}
if changed {
jt = func.create_jump_table(copied);
}
// Redo the match from above, but this time capture mutable references
match &mut func.dfg.insts[branch] {
InstructionData::BranchTable {
destination, table, ..
} => {
if *destination == dest_block {
*destination = middle_block;
}
*table = jt;
}
_ => unreachable!(),
if *destination == dest_block {
*destination = middle_block;
}
let mut cur = FuncCursor::new(func).at_bottom(middle_block);