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Merged
merged 5 commits into from
Jul 19, 2019
Merged

No unions3 #318

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c88f7c5
remove dep on untagged unions
wez Jan 3, 2019
225f51a
add missing doc comments, use usize for the offsets
wez Jan 3, 2019
445a238
simplify union removal, and remove all traces of unions
wez Jan 4, 2019
2d578ba
fixup padding of fields emitted after a union!
wez Jan 4, 2019
36a661e
inline the union accessors
wez Jan 4, 2019
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6 changes: 0 additions & 6 deletions src/generate/device.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,12 +48,6 @@ pub fn render(
#![no_std]
});

if nightly {
out.push(quote! {
#![feature(untagged_unions)]
});
}

match target {
Target::CortexM => {
out.push(quote! {
Expand Down
219 changes: 67 additions & 152 deletions src/generate/peripheral.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -213,24 +213,9 @@ impl Region {
self.shortest_ident()
}
}
/// Return a description of this region
fn description(&self) -> String {
let mut result = String::new();
for f in &self.fields {
// In the Atmel SVDs the union variants all tend to
// have the same description. Rather than emitting
// the same text three times over, only join in the
// text from the other variants if it is different.
// This isn't a foolproof way of emitting the most
// reasonable short description, but it's good enough.
if f.description != result {
if !result.is_empty() {
result.push(' ');
}
result.push_str(&f.description);
}
}
result

fn is_union(&self) -> bool {
self.fields.len() > 1
}
}

Expand Down Expand Up @@ -318,10 +303,6 @@ impl FieldRegions {
Ok(())
}

pub fn is_union(&self) -> bool {
self.regions.len() == 1 && self.regions[0].fields.len() > 1
}

/// Resolves type name conflicts
pub fn resolve_idents(&mut self) -> Result<()> {
let idents: Vec<_> = {
Expand Down Expand Up @@ -358,86 +339,11 @@ fn register_or_cluster_block(
ercs: &[RegisterCluster],
defs: &Defaults,
name: Option<&str>,
nightly: bool,
) -> Result<Tokens> {
if nightly {
register_or_cluster_block_nightly(ercs, defs, name)
} else {
register_or_cluster_block_stable(ercs, defs, name)
}
}

fn register_or_cluster_block_stable(
ercs: &[RegisterCluster],
defs: &Defaults,
name: Option<&str>,
_nightly: bool,
) -> Result<Tokens> {
let mut fields = Tokens::new();
// enumeration of reserved fields
let mut i = 0;
// offset from the base address, in bytes
let mut offset = 0;

let ercs_expanded = expand(ercs, defs, name)?;

for reg_block_field in ercs_expanded {
let pad = if let Some(pad) = reg_block_field.offset.checked_sub(offset) {
pad
} else {
warn!(
"{:?} overlaps with another register block at offset {}. \
Ignoring.",
reg_block_field.field.ident, reg_block_field.offset
);
continue;
};

if pad != 0 {
let name = Ident::new(format!("_reserved{}", i));
let pad = pad as usize;
fields.append(quote! {
#name : [u8; #pad],
});
i += 1;
}

let comment = &format!(
"0x{:02x} - {}",
reg_block_field.offset,
util::escape_brackets(util::respace(&reg_block_field.description).as_ref()),
)[..];

fields.append(quote! {
#[doc = #comment]
});

reg_block_field.field.to_tokens(&mut fields);
Ident::new(",").to_tokens(&mut fields);

offset = reg_block_field.offset + reg_block_field.size / BITS_PER_BYTE;
}

let name = Ident::new(match name {
Some(name) => name.to_sanitized_upper_case(),
None => "RegisterBlock".into(),
});

Ok(quote! {
/// Register block
#[repr(C)]
pub struct #name {
#fields
}
})
}

fn register_or_cluster_block_nightly(
ercs: &[RegisterCluster],
defs: &Defaults,
name: Option<&str>,
) -> Result<Tokens> {
let mut fields = Tokens::new();
let mut helper_types = Tokens::new();
let mut accessors = Tokens::new();
let mut have_accessors = false;

let ercs_expanded = expand(ercs, defs, name)?;

Expand All @@ -448,10 +354,9 @@ fn register_or_cluster_block_nightly(
regions.add(reg_block_field)?;
}

let block_is_union = regions.is_union();
// We need to compute the idents of each register/union block first to make sure no conflicts exists.
regions.resolve_idents()?;
// The end of the region from the prior iteration of the loop
// The end of the region for which we previously emitted a field into `fields`
let mut last_end = 0;

for (i, region) in regions.regions.iter().enumerate() {
Expand All @@ -465,86 +370,96 @@ fn register_or_cluster_block_nightly(
});
}

last_end = region.end;

let mut region_fields = Tokens::new();
let is_region_a_union = region.is_union();

for reg_block_field in &region.fields {
if reg_block_field.offset != region.offset {
// TODO: need to emit padding for this case.
// Happens for freescale_mkl43z4
warn!(
"field {:?} has different offset {} than its union container {}",
reg_block_field.field.ident, reg_block_field.offset, region.offset
);
}
let comment = &format!(
"0x{:02x} - {}",
reg_block_field.offset,
util::escape_brackets(util::respace(&reg_block_field.description).as_ref()),
)[..];

region_fields.append(quote! {
#[doc = #comment]
});

reg_block_field.field.to_tokens(&mut region_fields);
Ident::new(",").to_tokens(&mut region_fields);
}

if region.fields.len() > 1 && !block_is_union {
let (type_name, name) = match region.ident.clone() {
Some(prefix) => (
Ident::new(format!("{}_UNION", prefix.to_sanitized_upper_case())),
Ident::new(prefix),
),
// If we can't find a name, fall back to the region index as a
// unique-within-this-block identifier counter.
None => {
let ident = Ident::new(format!("U{}", i));
(ident.clone(), ident)
}
};
if is_region_a_union {
let name = &reg_block_field.field.ident;
let mut_name = Ident::new(format!("{}_mut", name.as_ref().unwrap()));
let ty = &reg_block_field.field.ty;
let offset = reg_block_field.offset as usize;
have_accessors = true;
accessors.append(quote! {
#[doc = #comment]
#[inline(always)]
pub fn #name(&self) -> &#ty {
unsafe {
&*(((self as *const Self) as *const u8).add(#offset) as *const #ty)
}
}

let description = region.description();
#[doc = #comment]
#[inline(always)]
pub fn #mut_name(&self) -> &mut #ty {
unsafe {
&mut *(((self as *const Self) as *mut u8).add(#offset) as *mut #ty)
}
}
});
} else {
region_fields.append(quote! {
#[doc = #comment]
});

helper_types.append(quote! {
#[doc = #description]
#[repr(C)]
pub union #type_name {
#region_fields
}
});
reg_block_field.field.to_tokens(&mut region_fields);
Ident::new(",").to_tokens(&mut region_fields);
}
}

fields.append(quote! {
#[doc = #description]
pub #name: #type_name
});
Ident::new(",").to_tokens(&mut fields);
} else {
if !is_region_a_union {
fields.append(&region_fields);
} else {
// Emit padding for the items that we're not emitting
// as fields so that subsequent fields have the correct
// alignment in the struct. We could omit this and just
// not updated `last_end`, so that the padding check in
// the outer loop kicks in, but it is nice to be able to
// see that the padding is attributed to a union when
// visually inspecting the alignment in the struct.
//
// Include the computed ident for the union in the padding
// name, along with the region number, falling back to
// the offset and end in case we couldn't figure out a
// nice identifier.
let name = Ident::new(format!("_reserved_{}_{}", i, region.compute_ident().unwrap_or_else(|| format!("{}_{}", region.offset, region.end))));
let pad = (region.end - region.offset) as usize;
fields.append(quote! {
#name: [u8; #pad],
})
}
last_end = region.end;
}

let name = Ident::new(match name {
Some(name) => name.to_sanitized_upper_case(),
None => "RegisterBlock".into(),
});

let block_type = if block_is_union {
Ident::new("union")
let accessors = if have_accessors {
quote! {
impl #name {
#accessors
}
}
} else {
Ident::new("struct")
quote! {}
};

Ok(quote! {
/// Register block
#[repr(C)]
pub #block_type #name {
pub struct #name {
#fields
}

#helper_types
#accessors
})
}

Expand Down