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Wasm control stack entries only need the number of return types.

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This eliminates heap-allocated vectors which stored the actual types.
This commit is contained in:
Dan Gohman
2017-09-25 12:48:31 -07:00
parent 55e48ce7aa
commit 36585ddc4f
4 changed files with 44 additions and 46 deletions
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33
lib/wasm/src/state.rs
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@@ -3,7 +3,7 @@
//! The `TranslationState` struct defined in this module is used to keep track of the WebAssembly
//! value and control stacks during the translation of a single function.
use cretonne::ir::{self, Ebb, Inst, Type, Value};
use cretonne::ir::{self, Ebb, Inst, Value};
use runtime::{FuncEnvironment, GlobalValue};
use std::collections::HashMap;
use translation_utils::{GlobalIndex, MemoryIndex, SignatureIndex, FunctionIndex};
@@ -12,7 +12,7 @@ use translation_utils::{GlobalIndex, MemoryIndex, SignatureIndex, FunctionIndex}
/// fields:
///
/// - `destination`: reference to the `Ebb` that will hold the code after the control block;
/// - `return_values`: types of the values returned by the control block;
/// - `num_return_values`: number of values returned by the control block;
/// - `original_stack_size`: size of the value stack at the beginning of the control block.
///
/// Moreover, the `if` frame has the `branch_inst` field that points to the `brz` instruction
@@ -23,20 +23,20 @@ pub enum ControlStackFrame {
If {
destination: Ebb,
branch_inst: Inst,
return_values: Vec<Type>,
num_return_values: usize,
original_stack_size: usize,
reachable: bool,
},
Block {
destination: Ebb,
return_values: Vec<Type>,
num_return_values: usize,
original_stack_size: usize,
reachable: bool,
},
Loop {
destination: Ebb,
header: Ebb,
return_values: Vec<Type>,
num_return_values: usize,
original_stack_size: usize,
reachable: bool,
},
@@ -44,11 +44,11 @@ pub enum ControlStackFrame {
/// Helper methods for the control stack objects.
impl ControlStackFrame {
pub fn return_values(&self) -> &[Type] {
pub fn num_return_values(&self) -> usize {
match *self {
ControlStackFrame::If { ref return_values, .. } |
ControlStackFrame::Block { ref return_values, .. } |
ControlStackFrame::Loop { ref return_values, .. } => &return_values,
ControlStackFrame::If { num_return_values, .. } |
ControlStackFrame::Block { num_return_values, .. } |
ControlStackFrame::Loop { num_return_values, .. } => num_return_values,
}
}
pub fn following_code(&self) -> Ebb {
@@ -161,8 +161,7 @@ impl TranslationState {
sig.return_types
.iter()
.filter(|arg| arg.purpose == ir::ArgumentPurpose::Normal)
.map(|argty| argty.value_type)
.collect(),
.count(),
);
}
@@ -215,33 +214,33 @@ impl TranslationState {
}
// Push a block on the control stack.
pub fn push_block(&mut self, following_code: Ebb, result_types: Vec<Type>) {
pub fn push_block(&mut self, following_code: Ebb, num_result_types: usize) {
self.control_stack.push(ControlStackFrame::Block {
destination: following_code,
original_stack_size: self.stack.len(),
return_values: result_types,
num_return_values: num_result_types,
reachable: false,
});
}
// Push a loop on the control stack.
pub fn push_loop(&mut self, header: Ebb, following_code: Ebb, result_types: Vec<Type>) {
pub fn push_loop(&mut self, header: Ebb, following_code: Ebb, num_result_types: usize) {
self.control_stack.push(ControlStackFrame::Loop {
header,
destination: following_code,
original_stack_size: self.stack.len(),
return_values: result_types,
num_return_values: num_result_types,
reachable: false,
});
}
// Push an if on the control stack.
pub fn push_if(&mut self, branch_inst: Inst, following_code: Ebb, result_types: Vec<Type>) {
pub fn push_if(&mut self, branch_inst: Inst, following_code: Ebb, num_result_types: usize) {
self.control_stack.push(ControlStackFrame::If {
branch_inst,
destination: following_code,
original_stack_size: self.stack.len(),
return_values: result_types,
num_return_values: num_result_types,
reachable: false,
});
}