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Code generation for br_table.

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This commit is contained in:
losfair 2019-02-24 12:00:35 +08:00
parent b2f5f77094
commit dbebdf937f
1 changed files with 90 additions and 3 deletions
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93
lib/dynasm-backend/src/codegen_x64.rs
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@ -122,6 +122,7 @@ pub struct X64FunctionCode {
begin_offset: AssemblyOffset,
assembler: Option<Assembler>,
function_labels: Option<HashMap<usize, DynamicLabel>>,
br_table_data: Option<Vec<Vec<usize>>>,
returns: Vec<WpType>,
locals: Vec<Local>,
num_params: usize,
@ -134,6 +135,7 @@ pub struct X64FunctionCode {
pub struct X64ExecutionContext {
code: ExecutableBuffer,
functions: Vec<X64FunctionCode>,
br_table_data: Vec<Vec<usize>>,
}
impl ProtectedCaller for X64ExecutionContext {
@ -227,10 +229,11 @@ impl X64ModuleCodeGenerator {
impl ModuleCodeGenerator<X64FunctionCode, X64ExecutionContext> for X64ModuleCodeGenerator {
fn next_function(&mut self) -> Result<&mut X64FunctionCode, CodegenError> {
let (mut assembler, mut function_labels) = match self.functions.last_mut() {
let (mut assembler, mut function_labels, br_table_data) = match self.functions.last_mut() {
Some(x) => (
x.assembler.take().unwrap(),
x.function_labels.take().unwrap(),
x.br_table_data.take().unwrap(),
),
None => (
match Assembler::new() {
@ -242,6 +245,7 @@ impl ModuleCodeGenerator<X64FunctionCode, X64ExecutionContext> for X64ModuleCode
}
},
HashMap::new(),
vec![],
),
};
let begin_label = *function_labels
@ -262,6 +266,7 @@ impl ModuleCodeGenerator<X64FunctionCode, X64ExecutionContext> for X64ModuleCode
begin_offset: begin_offset,
assembler: Some(assembler),
function_labels: Some(function_labels),
br_table_data: Some(br_table_data),
returns: vec![],
locals: vec![],
num_params: 0,
@ -275,8 +280,8 @@ impl ModuleCodeGenerator<X64FunctionCode, X64ExecutionContext> for X64ModuleCode
}
fn finalize(mut self) -> Result<X64ExecutionContext, CodegenError> {
let mut assembler = match self.functions.last_mut() {
Some(x) => x.assembler.take().unwrap(),
let (mut assembler, mut br_table_data) = match self.functions.last_mut() {
Some(x) => (x.assembler.take().unwrap(), x.br_table_data.take().unwrap()),
None => {
return Err(CodegenError {
message: "no function",
@ -284,9 +289,16 @@ impl ModuleCodeGenerator<X64FunctionCode, X64ExecutionContext> for X64ModuleCode
}
};
let output = assembler.finalize().unwrap();
for table in &mut br_table_data {
for entry in table {
*entry = output.ptr(AssemblyOffset(*entry)) as usize;
}
}
Ok(X64ExecutionContext {
code: output,
functions: self.functions,
br_table_data: br_table_data,
})
}
@ -1201,6 +1213,30 @@ impl FunctionCodeGenerator for X64FunctionCode {
},
)?;
}
Operator::I32And => {
Self::emit_binop_i32(
assembler,
&mut self.value_stack,
|assembler, value_stack, left, right| {
dynasm!(
assembler
; and Rd(left as u8), Rd(right as u8)
);
},
)?;
}
Operator::I32Or => {
Self::emit_binop_i32(
assembler,
&mut self.value_stack,
|assembler, value_stack, left, right| {
dynasm!(
assembler
; or Rd(left as u8), Rd(right as u8)
);
},
)?;
}
Operator::I32Eq => {
Self::emit_binop_i32(
assembler,
@ -1488,6 +1524,57 @@ impl FunctionCodeGenerator for X64FunctionCode {
; =>no_br_label
);
}
Operator::BrTable { table } => {
let (targets, default_target) = match table.read_table() {
Ok(x) => x,
Err(_) => {
return Err(CodegenError {
message: "cannot read br table",
});
}
};
let cond_ty = Self::emit_pop_into_ax(assembler, &mut self.value_stack)?;
if cond_ty != WpType::I32 {
return Err(CodegenError {
message: "expecting i32 for BrTable condition",
});
}
let mut table = vec![0usize; targets.len()];
dynasm!(
assembler
; cmp eax, targets.len() as i32
; jae >default_br
; shl rax, 3
; push rcx
; mov rcx, QWORD table.as_ptr() as usize as i64
; add rax, rcx
; pop rcx
; mov rax, [rax] // assuming upper 32 bits of rax are zeroed
; jmp rax
);
for (i, target) in targets.iter().enumerate() {
let AssemblyOffset(offset) = assembler.offset();
table[i] = offset;
Self::emit_jmp(
assembler,
self.control_stack.as_ref().unwrap(),
&mut self.value_stack,
*target as usize,
)?; // This does not actually modify value_stack.
}
dynasm!(
assembler
; default_br:
);
Self::emit_jmp(
assembler,
self.control_stack.as_ref().unwrap(),
&mut self.value_stack,
default_target as usize,
)?;
self.br_table_data.as_mut().unwrap().push(table);
self.unreachable_depth = 1;
}
_ => unimplemented!(),
}
Ok(())