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Initial work towards getting post-return functions #310

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merged 1 commit into from
Sep 22, 2022
Merged

Initial work towards getting post-return functions #310

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98 changes: 81 additions & 17 deletions crates/gen-guest-c/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -450,15 +450,6 @@ impl C {
abort();
return ret;
}

__attribute__((weak, export_name(\"canonical_abi_free\")))
void canonical_abi_free(
void *ptr,
size_t size,
size_t align
) {
free(ptr);
}
");
}

Expand Down Expand Up @@ -518,12 +509,9 @@ impl C {
self.free(iface, t, "&ptr->ptr[i]");
self.src.c("}\n");
}
uwriteln!(
self.src.c,
"canonical_abi_free(ptr->ptr, ptr->len * {}, {});",
self.sizes.size(t),
self.sizes.align(t),
);
uwriteln!(self.src.c, "if (ptr->len > 0) {{");
uwriteln!(self.src.c, "free(ptr->ptr);");
uwriteln!(self.src.c, "}}");
}

TypeDefKind::Variant(v) => {
Expand Down Expand Up @@ -1120,6 +1108,42 @@ impl Generator for C {
self.src.c(&src);
self.src.c("}\n");

if iface.guest_export_needs_post_return(func) {
uwriteln!(
self.src.c,
"__attribute__((export_name(\"cabi_post_{}\")))",
func.name
);
uwrite!(self.src.c, "void {import_name}_post_return(");

let mut params = Vec::new();
let mut c_sig = CSig {
name: String::from("INVALID"),
sig: String::from("INVALID"),
params: Vec::new(),
ret: Return {
return_multiple: false,
scalar: None,
retptrs: Vec::new(),
},
retptrs: Vec::new(),
};
for (i, result) in sig.results.iter().enumerate() {
let name = format!("arg{i}");
uwrite!(self.src.c, "{} {name}", wasm_type(*result));
c_sig.params.push((false, name.clone()));
params.push(name);
}
self.src.c.push_str(") {\n");

let mut f = FunctionBindgen::new(self, c_sig, &import_name);
f.params = params;
iface.post_return(func, &mut f);
let FunctionBindgen { src, .. } = f;
self.src.c(&src);
self.src.c("}\n");
}

let src = mem::replace(&mut self.src, prev);
self.funcs
.entry(iface.name.to_string())
Expand Down Expand Up @@ -1299,7 +1323,9 @@ impl Generator for C {
}}

void {0}_string_free({0}_string_t *ret) {{
canonical_abi_free(ret->ptr, ret->len, 1);
if (ret->len > 0) {{
free(ret->ptr);
}}
ret->ptr = NULL;
ret->len = 0;
}}
Expand Down Expand Up @@ -2204,9 +2230,47 @@ impl Bindgen for FunctionBindgen<'_> {
self.load_ext("int16_t", *offset, operands, results)
}

Instruction::Free { .. } => {
Instruction::GuestDeallocate { .. } => {
uwriteln!(self.src, "free((void*) ({}));", operands[0]);
}
Instruction::GuestDeallocateString => {
uwriteln!(self.src, "if (({}) > 0) {{", operands[1]);
uwriteln!(self.src, "free((void*) ({}));", operands[0]);
uwriteln!(self.src, "}}");
}
Instruction::GuestDeallocateVariant { blocks } => {
let blocks = self
.blocks
.drain(self.blocks.len() - blocks..)
.collect::<Vec<_>>();

uwriteln!(self.src, "switch ((int32_t) {}) {{", operands[0]);
for (i, (block, results)) in blocks.into_iter().enumerate() {
assert!(results.is_empty());
uwriteln!(self.src, "case {}: {{", i);
self.src.push_str(&block);
self.src.push_str("break;\n}\n");
}
self.src.push_str("}\n");
}
Instruction::GuestDeallocateList { element } => {
let (body, results) = self.blocks.pop().unwrap();
assert!(results.is_empty());
let ptr = self.locals.tmp("ptr");
let len = self.locals.tmp("len");
uwriteln!(self.src, "int32_t {ptr} = {};", operands[0]);
uwriteln!(self.src, "int32_t {len} = {};", operands[1]);
let i = self.locals.tmp("i");
uwriteln!(self.src, "for (int32_t {i} = 0; {i} < {len}; {i}++) {{");
let size = self.gen.sizes.size(element);
uwriteln!(self.src, "int32_t base = {ptr} + {i} * {size};");
uwriteln!(self.src, "(void) base;");
uwrite!(self.src, "{body}");
uwriteln!(self.src, "}}");
uwriteln!(self.src, "if ({len} > 0) {{");
uwriteln!(self.src, "free((void*) ({ptr}));");
uwriteln!(self.src, "}}");
}

i => unimplemented!("{:?}", i),
}
Expand Down
137 changes: 106 additions & 31 deletions crates/gen-guest-rust/src/lib.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -528,23 +528,20 @@ impl Generator for RustWasm {
fn export(&mut self, iface: &Interface, func: &Function) {
let iface_name = iface.name.to_snake_case();

self.src.push_str("#[export_name = \"");
match &iface.module {
let name_mangled = iface.mangle_funcname(func);
let name_snake = func.name.to_snake_case();
let name = match &iface.module {
Some(module) => {
self.src.push_str(module);
self.src.push_str("#");
self.src.push_str(&iface.mangle_funcname(func));
format!("{module}#{}", name_mangled)
}
None => {
self.src.push_str(&self.opts.symbol_namespace);
self.src.push_str(&iface.mangle_funcname(func));
}
}
self.src.push_str("\"]\n");
None => format!("{}{}", self.opts.symbol_namespace, name_mangled),
};

self.src.push_str(&format!("#[export_name = \"{name}\"]\n"));
self.src.push_str("unsafe extern \"C\" fn __wit_bindgen_");
self.src.push_str(&iface_name);
self.src.push_str("_");
self.src.push_str(&func.name.to_snake_case());
self.src.push_str(&name_snake);
self.src.push_str("(");
let sig = iface.wasm_signature(AbiVariant::GuestExport, func);
let mut params = Vec::new();
Expand Down Expand Up @@ -594,6 +591,37 @@ impl Generator for RustWasm {
self.src.push_str(&String::from(src));
self.src.push_str("}\n");

if iface.guest_export_needs_post_return(func) {
self.src.push_str(&format!(
"#[export_name = \"{}cabi_post_{}\"]\n",
self.opts.symbol_namespace, func.name,
));
self.src.push_str(&format!(
"unsafe extern \"C\" fn __wit_bindgen_{iface_name}_{name_snake}_post_return("
));
let mut params = Vec::new();
for (i, result) in sig.results.iter().enumerate() {
let name = format!("arg{}", i);
self.src.push_str(&name);
self.src.push_str(": ");
self.wasm_type(*result);
self.src.push_str(", ");
params.push(name);
}
self.src.push_str(") {\n");

let mut f = FunctionBindgen::new(self, params);
iface.post_return(func, &mut f);
let FunctionBindgen {
needs_cleanup_list,
src,
..
} = f;
assert!(!needs_cleanup_list);
self.src.push_str(&String::from(src));
self.src.push_str("}\n");
}

let prev = mem::take(&mut self.src);
self.in_trait = true;
let mut sig = FnSig::default();
Expand Down Expand Up @@ -1290,10 +1318,7 @@ impl Bindgen for FunctionBindgen<'_> {
results.push(len);
}

Instruction::ListCanonLift { free, .. } => {
// This only happens when we're receiving a list from the
// outside world, so `free` should always be `Some`.
assert!(free.is_some());
Instruction::ListCanonLift { .. } => {
let tmp = self.tmp();
let len = format!("len{}", tmp);
self.push_str(&format!("let {} = {} as usize;\n", len, operands[1]));
Expand Down Expand Up @@ -1324,10 +1349,7 @@ impl Bindgen for FunctionBindgen<'_> {
results.push(len);
}

Instruction::StringLift { free, .. } => {
// This only happens when we're receiving a string from the
// outside world, so `free` should always be `Some`.
assert!(free.is_some());
Instruction::StringLift => {
let tmp = self.tmp();
let len = format!("len{}", tmp);
self.push_str(&format!("let {} = {} as usize;\n", len, operands[1]));
Expand Down Expand Up @@ -1383,10 +1405,7 @@ impl Bindgen for FunctionBindgen<'_> {
}
}

Instruction::ListLift { element, free, .. } => {
// This only happens when we're receiving a list from the
// outside world, so `free` should always be `Some`.
assert!(free.is_some());
Instruction::ListLift { element, .. } => {
let body = self.blocks.pop().unwrap();
let tmp = self.tmp();
let size = self.gen.sizes.size(element);
Expand Down Expand Up @@ -1421,7 +1440,7 @@ impl Bindgen for FunctionBindgen<'_> {
self.push_str("}\n");
results.push(result);
self.push_str(&format!(
"if {len} != 0 {{\nstd::alloc::dealloc({base} as *mut _, std::alloc::Layout::from_size_align_unchecked(({len} as usize) * {size}, {align}));\n}}\n",
"wit_bindgen_guest_rust::rt::dealloc({base}, ({len} as usize) * {size}, {align});\n",
));
}

Expand Down Expand Up @@ -1575,16 +1594,72 @@ impl Bindgen for FunctionBindgen<'_> {
}

Instruction::Malloc { .. } => unimplemented!(),
Instruction::Free {
free: _,
size,
align,
} => {

Instruction::GuestDeallocate { size, align } => {
self.push_str(&format!(
"wit_bindgen_guest_rust::rt::canonical_abi_free({} as *mut u8, {}, {});\n",
"wit_bindgen_guest_rust::rt::dealloc({}, {}, {});\n",
operands[0], size, align
));
}

Instruction::GuestDeallocateString => {
self.push_str(&format!(
"wit_bindgen_guest_rust::rt::dealloc({}, ({}) as usize, 1);\n",
operands[0], operands[1],
));
}

Instruction::GuestDeallocateVariant { blocks } => {
let max = blocks - 1;
let blocks = self
.blocks
.drain(self.blocks.len() - blocks..)
.collect::<Vec<_>>();
let op0 = &operands[0];
self.src.push_str(&format!("match {op0} {{\n"));
for (i, block) in blocks.into_iter().enumerate() {
let pat = if i == max {
String::from("_")
} else {
i.to_string()
};
self.src.push_str(&format!("{pat} => {block},\n"));
}
self.src.push_str("}\n");
}

Instruction::GuestDeallocateList { element } => {
let body = self.blocks.pop().unwrap();
let tmp = self.tmp();
let size = self.gen.sizes.size(element);
let align = self.gen.sizes.align(element);
let len = format!("len{tmp}");
let base = format!("base{tmp}");
self.push_str(&format!(
"let {base} = {operand0};\n",
operand0 = operands[0]
));
self.push_str(&format!(
"let {len} = {operand1};\n",
operand1 = operands[1]
));

if body != "()" {
self.push_str("for i in 0..");
self.push_str(&len);
self.push_str(" {\n");
self.push_str("let base = ");
self.push_str(&base);
self.push_str(" + i *");
self.push_str(&size.to_string());
self.push_str(";\n");
self.push_str(&body);
self.push_str("\n}\n");
}
self.push_str(&format!(
"wit_bindgen_guest_rust::rt::dealloc({base}, ({len} as usize) * {size}, {align});\n",
));
}
}
}
}
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