From 0e3f745fb203c0df47ca2f587469dc2bc3ed7363 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvarkus@gmail.com>
Date: Fri, 19 Feb 2021 16:40:44 -0500
Subject: [PATCH] [msl] derive thiserror

---
 src/back/glsl/mod.rs   |  2 +-
 src/back/msl/mod.rs    | 47 ++++++++++++++++--------------------------
 src/back/msl/writer.rs | 31 +++++++++++++++-------------
 src/back/spv/writer.rs |  2 +-
 src/proc/validator.rs  |  2 +-
 5 files changed, 38 insertions(+), 46 deletions(-)

diff --git a/src/back/glsl/mod.rs b/src/back/glsl/mod.rs
index ae22cb213e..6a0a74a947 100644
--- a/src/back/glsl/mod.rs
+++ b/src/back/glsl/mod.rs
@@ -44,7 +44,7 @@
 pub use features::Features;
 
 use crate::{
-    proc::{analyzer::Analysis, NameKey, Namer, ResolveContext, TypifyError, Typifier},
+    proc::{analyzer::Analysis, NameKey, Namer, ResolveContext, Typifier, TypifyError},
     Arena, ArraySize, BinaryOperator, Binding, BuiltIn, Bytes, ConservativeDepth, Constant,
     ConstantInner, DerivativeAxis, Expression, FastHashMap, Function, GlobalVariable, Handle,
     ImageClass, Interpolation, LocalVariable, Module, RelationalFunction, ScalarKind, ScalarValue,
diff --git a/src/back/msl/mod.rs b/src/back/msl/mod.rs
index 585593ab50..9adeed2c62 100644
--- a/src/back/msl/mod.rs
+++ b/src/back/msl/mod.rs
@@ -56,43 +56,30 @@ enum ResolvedBinding {
 
 // Note: some of these should be removed in favor of proper IR validation.
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 pub enum Error {
-    IO(IoError),
-    Utf8(FromUtf8Error),
-    Type(TypifyError),
+    #[error(transparent)]
+    IO(#[from] IoError),
+    #[error(transparent)]
+    Utf8(#[from] FromUtf8Error),
+    #[error(transparent)]
+    Type(#[from] TypifyError),
+    #[error("bind source for {0:?} is missing from the map")]
     MissingBindTarget(BindSource),
-    InvalidImageAccess(crate::StorageAccess),
-    BadName(String),
+    #[error("bind target {0:?} is empty")]
     UnimplementedBindTarget(BindTarget),
+    #[error("composing of {0:?} is not implemented yet")]
     UnsupportedCompose(Handle<crate::Type>),
+    #[error("operation {0:?} is not implemented yet")]
     UnsupportedBinaryOp(crate::BinaryOperator),
-    UnexpectedSampleLevel(crate::SampleLevel),
+    #[error("standard function '{0}' is not implemented yet")]
     UnsupportedCall(String),
-    UnsupportedDynamicArrayLength,
+    #[error("feature '{0}' is not implemented yet")]
     FeatureNotImplemented(String),
-    /// The source IR is not valid.
+    #[error("module is not valid")]
     Validation,
 }
 
-impl From<IoError> for Error {
-    fn from(e: IoError) -> Self {
-        Error::IO(e)
-    }
-}
-
-impl From<FromUtf8Error> for Error {
-    fn from(e: FromUtf8Error) -> Self {
-        Error::Utf8(e)
-    }
-}
-
-impl From<TypifyError> for Error {
-    fn from(e: TypifyError) -> Self {
-        Error::Type(e)
-    }
-}
-
 #[derive(Clone, Copy, Debug)]
 enum LocationMode {
     VertexInput,
@@ -155,8 +142,10 @@ impl Options {
                     group,
                     binding,
                 };
-                ResolvedBinding::Resource(
-                    self.binding_map.get(&source).cloned().
+                self.binding_map
+                    .get(&source)
+                    .cloned()
+                    .map(ResolvedBinding::Resource)
                     .ok_or(Error::MissingBindTarget(source))
             }
             None => {
diff --git a/src/back/msl/writer.rs b/src/back/msl/writer.rs
index 99bc0974cd..69086c260e 100644
--- a/src/back/msl/writer.rs
+++ b/src/back/msl/writer.rs
@@ -680,20 +680,23 @@ impl<W: Write> Writer<W> {
             } => {
                 self.put_local_call(function, arguments, context)?;
             }
-            crate::Expression::ArrayLength(expr) => match *self
-                .typifier
-                .get(expr, &context.module.types)
-            {
-                crate::TypeInner::Array {
-                    size: crate::ArraySize::Constant(const_handle),
-                    ..
-                } => {
-                    let size_str = &self.names[&NameKey::Constant(const_handle)];
-                    write!(self.out, "{}", size_str)?;
+            crate::Expression::ArrayLength(expr) => {
+                match *self.typifier.get(expr, &context.module.types) {
+                    crate::TypeInner::Array {
+                        size: crate::ArraySize::Constant(const_handle),
+                        ..
+                    } => {
+                        let size_str = &self.names[&NameKey::Constant(const_handle)];
+                        write!(self.out, "{}", size_str)?;
+                    }
+                    crate::TypeInner::Array { .. } => {
+                        return Err(Error::FeatureNotImplemented(
+                            "dynamic array size".to_string(),
+                        ))
+                    }
+                    _ => return Err(Error::Validation),
                 }
-                crate::TypeInner::Array { .. } => return Err(Error::UnsupportedDynamicArrayLength),
-                _ => return Err(Error::Validation),
-            },
+            }
         }
         Ok(())
     }
@@ -1025,7 +1028,7 @@ impl<W: Write> Writer<W> {
                             } else if global.storage_access.contains(crate::StorageAccess::LOAD) {
                                 "read"
                             } else {
-                                return Err(Error::InvalidImageAccess(global.storage_access));
+                                return Err(Error::Validation);
                             };
                             ("texture", "", format.into(), access)
                         }
diff --git a/src/back/spv/writer.rs b/src/back/spv/writer.rs
index a6c279358d..3476b480c2 100644
--- a/src/back/spv/writer.rs
+++ b/src/back/spv/writer.rs
@@ -4,7 +4,7 @@ use crate::{
     arena::{Arena, Handle},
     proc::{
         analyzer::{Analysis, FunctionInfo},
-        Layouter, ResolveContext, TypifyError, Typifier,
+        Layouter, ResolveContext, Typifier, TypifyError,
     },
 };
 use spirv::Word;
diff --git a/src/proc/validator.rs b/src/proc/validator.rs
index 55bc960235..4188c8ba36 100644
--- a/src/proc/validator.rs
+++ b/src/proc/validator.rs
@@ -1,6 +1,6 @@
 use super::{
     analyzer::{Analysis, AnalysisError, FunctionInfo, GlobalUse},
-    typifier::{TypifyError, ResolveContext, Typifier},
+    typifier::{ResolveContext, Typifier, TypifyError},
 };
 use crate::arena::{Arena, Handle};
 use bit_set::BitSet;