error: Cluster USART has no determinable `size` field

[wez]

I get this error with ATSAMD21G18A.svd

I'm not opposed to rolling up my sleeves to help fix this if someone with context can tell me roughly what needs to happen. I'm a fast learner!

I see this with 631ab3e

error: Cluster USART has no determinable `size` field
caused by: Warning! overlap while calculating Register Size within a Cluster! Cluster contents may be incorrectly aligned!
backtrace: stack backtrace:
   0:     0x55bb5fecc8d4 - backtrace::backtrace::libunwind::trace::hbf9f65f12207138f
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.5/src/backtrace/libunwind.rs:53
                         - backtrace::backtrace::trace::hd67ff4d2334f7ed6
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.5/src/backtrace/mod.rs:42
   1:     0x55bb5feca63c - backtrace::capture::Backtrace::new_unresolved::h642c5b6c9400d9d5
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.5/src/capture.rs:88
   2:     0x55bb5feca58e - backtrace::capture::Backtrace::new::h6b30f701e69e550b
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.5/src/capture.rs:63
   3:     0x55bb5fec76b6 - error_chain::make_backtrace::hc918c7599bfaea64
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.11.0/src/lib.rs:616
   4:     0x55bb5fec772f - <error_chain::State as core::default::Default>::default::h548074ab69a8084d
                        at /home/wez/.cargo/registry/src/github.com-1ecc6299db9ec823/error-chain-0.11.0/src/lib.rs:710
   5:     0x55bb5fde81bd - svd2rust::errors::Error::from_kind::hd36a5afffca28cb6
                        at /home/wez/github/svd2rust/<impl_error_chain_processed macros>:53
   6:     0x55bb5fde83b9 - <svd2rust::errors::Error as core::convert::From<alloc::string::String>>::from::hd00d5407c74d1305
                        at src/errors.rs:1
   7:     0x55bb5fd7ef70 - svd2rust::generate::peripheral::cluster_size_in_bits::ha74a72683196d068
                        at src/generate/peripheral.rs:210
   8:     0x55bb5fe1a6ca - svd2rust::generate::peripheral::expand_cluster::{{closure}}::hbe5bc632c7386e96
                        at src/generate/peripheral.rs:246
   9:     0x55bb5fd875dc - <core::result::Result<T, E>>::or_else::he8ffab4c771caf21
                        at /checkout/src/libcore/result.rs:691
  10:     0x55bb5fd7f86d - svd2rust::generate::peripheral::expand_cluster::h447512a0d57fb8aa
                        at src/generate/peripheral.rs:243
  11:     0x55bb5fd7e89f - svd2rust::generate::peripheral::expand::h8fc1592519c5606e
                        at src/generate/peripheral.rs:191
  12:     0x55bb5fd7d6c8 - svd2rust::generate::peripheral::register_or_cluster_block::h682fffe6a6a9ec45
                        at src/generate/peripheral.rs:125
  13:     0x55bb5fd7c792 - svd2rust::generate::peripheral::render::h008b4049f11701b1
                        at src/generate/peripheral.rs:78
  14:     0x55bb5fde0b5f - svd2rust::generate::device::render::h25c68a216b631a00
                        at src/generate/device.rs:128
  15:     0x55bb5fe25453 - svd2rust::run::hb3070a0e4fb05ceb
                        at src/main.rs:84
  16:     0x55bb5fe25b86 - svd2rust::main::h76b2401efe189507
                        at src/main.rs:99
  17:     0x55bb5fde9031 - std::rt::lang_start::{{closure}}::hf182223c25a0e056
                        at /checkout/src/libstd/rt.rs:74
  18:     0x55bb60082ee7 - std::rt::lang_start_internal::{{closure}}::h6683f918b5e41df1
                        at libstd/rt.rs:59
                         - std::panicking::try::do_call::h9980f1b0ce760291
                        at libstd/panicking.rs:306
  19:     0x55bb6008ca8e - __rust_maybe_catch_panic
                        at libpanic_unwind/lib.rs:102
  20:     0x55bb60083683 - std::panicking::try::h2b055bf317f9a3ac
                        at libstd/panicking.rs:285
                         - std::panic::catch_unwind::h8402e9b2ba9c09e5
                        at libstd/panic.rs:361
                         - std::rt::lang_start_internal::h591dc8f1c9bda6fc
                        at libstd/rt.rs:58
  21:     0x55bb5fde9011 - std::rt::lang_start::hcbc8bede4be6939e
                        at /checkout/src/libstd/rt.rs:74
  22:     0x55bb5fe2613d - main
  23:     0x7f4a2898a1c0 - __libc_start_main
  24:     0x55bb5fd7b4a9 - _start
  25:                0x0 - <unknown>

[wez]

I added more context to the warning:

caused by: Warning! overlap while calculating Register Size within a Cluster! Cluster contents may be incorrectly aligned! Single(
    RegisterInfo {
        name: "BAUD_FRAC_MODE",
        description: "USART Baud Rate",
        address_offset: 12,
        size: Some(
            16
        ),
        access: None,
        reset_value: None,
        reset_mask: None,
        fields: Some(
            [
                Field {
                    name: "BAUD",
                    description: Some(
                        "Baud Rate Value"
                    ),
                    bit_range: BitRange {
                        offset: 0,
                        width: 13
                    },
                    access: None,
                    enumerated_values: [],
                    write_constraint: None,
                    _extensible: ()
                },
                Field {
                    name: "FP",
                    description: Some(
                        "Fractional Part"
                    ),
                    bit_range: BitRange {
                        offset: 13,
                        width: 3
                    },
                    access: None,
                    enumerated_values: [],
                    write_constraint: None,
                    _extensible: ()
                }
            ]
        ),
        write_constraint: None,
        _extensible: ()
    }
)

[wez]

Here's the offending sequence in the svd file:

        <register>
          <name>BAUD</name>
          <description>USART Baud Rate</description>
          <addressOffset>0x0C</addressOffset>
          <size>16</size>
          <fields>
            <field>
              <name>BAUD</name>
              <description>Baud Rate Value</description>
              <bitOffset>0</bitOffset>
              <bitWidth>16</bitWidth>
            </field>
          </fields>
        </register>
        <register>
          <name>BAUD_FRAC_MODE</name>
          <description>USART Baud Rate</description>
          <alternateRegister>BAUD</alternateRegister>
          <addressOffset>0x0C</addressOffset>
          <size>16</size>
          <fields>
            <field>
              <name>BAUD</name>
              <description>Baud Rate Value</description>
              <bitOffset>0</bitOffset>
              <bitWidth>13</bitWidth>
            </field>
            <field>
              <name>FP</name>
              <description>Fractional Part</description>
              <bitOffset>13</bitOffset>
              <bitWidth>3</bitWidth>
            </field>
          </fields>
        </register>

[wez]

May be another incarnation of #16 ?

[wez]

I've hacked in some code to skip entries that have an alternateRegister, which seems to fit with the default disposition of #16 and probably fine (caveat: I haven't read any specs :-p)
I still had some more overlaps though, so I modified the code to skip entries that overlap:

diff --git a/src/generate/peripheral.rs b/src/generate/peripheral.rs
index 90df735..7480e3a 100644
--- a/src/generate/peripheral.rs
+++ b/src/generate/peripheral.rs
@@ -207,11 +207,16 @@ fn cluster_size_in_bits(info: &ClusterInfo, defs: &Defaults) -> Result<u32> {
     for c in &info.children {
         size += match *c {
             Either::Left(ref reg) => {
-                let pad = reg.address_offset.checked_sub(offset)
-                .ok_or_else(||
-                    format!("Warning! overlap while calculating Register Size within a Cluster! Cluster contents may be incorrectly aligned!"))?
-                * BITS_PER_BYTE;
-
+                if reg.alternate_register.is_some() {
+                    0
+                } else {
+                let pad = match reg.address_offset.checked_sub(offset) {
+                    Some(size) => size * BITS_PER_BYTE,
+                    None => {
+                        eprintln!("Warning! overlap while calculating Register Size within a Cluster! Cluster contents may be incorrectly aligned! offset={} {:#?}", offset, reg);
+                        continue;
+                    }
+                };

                 let reg_size: u32 = expand_register(reg, defs, None)?
                     .iter()
@@ -219,6 +224,7 @@ fn cluster_size_in_bits(info: &ClusterInfo, defs: &Defaults) -> Result<u32> {
                     .sum();

                 pad + reg_size
+                }
             }
             Either::Right(ref clust) => {
                 let pad = clust.address_offset.checked_sub(offset)

[wez]

Thinking about this a bit more, can we simplify this?

If addressOffset is the start of the range of bits for the register (relative to its container; the cluster) and we can compute the bit width of a group, then we know the end of the range of bits for each of those registers.

The size is therefore the maximum end position for all of its children.

Am I missing something there?

/// Recursively calculate the size of a cluster. A cluster's size is the maximum
/// end position of its recursive children.
fn cluster_size_in_bits(info: &ClusterInfo, defs: &Defaults) -> Result<u32> {
    let mut size = 0;

    for c in &info.children {
        let end = match *c {
            Either::Left(ref reg) => {
                let reg_size: u32 = expand_register(reg, defs, None)?
                    .iter()
                    .map(|rbf| rbf.size)
                    .sum();

                (reg.address_offset * BITS_PER_BYTE) + reg_size
            }
            Either::Right(ref clust) => {
                (clust.address_offset * BITS_PER_BYTE) + cluster_size_in_bits(clust, defs)?
            }
        };

        size = size.max(end);
    }
    Ok(size)
}

[jamesmunns]

Hey @wez, contributions are welcome :) I'll try and take a look at this issue (and your solutions) this evening.

[bachp]

@wez @jamesmunns Did you already solve this? I also ran into this issue with a newer SVD file for the same chip from Atmel ATSAMD21G18AU.svd

I tried with the current master (fb54754) but still got this error.

[wez]

@bachp I have WIP here: https://github.com/wez/atsamd21-rs
There are a couple of issues with the code gen that block my patches from being merged, and I hope to find time to address those in the coming week