Add get_compilation_info (#5410)

* Add get_compilation_info API

* Rename glsl ParseError to ParseErrors

* Document ParseError label order

* Update line_position to count UTF-8 bytes

Author: stefnotch

CHANGELOG.md

@@ -73,6 +73,27 @@ Due to a specification change `write_timestamp` is no longer supported on WebGPU
 
 By @wumpf in [#5188](https://github.com/gfx-rs/wgpu/pull/5188)
 
+#### Querying shader compilation errors
+
+Wgpu now supports querying [shader compilation info](https://www.w3.org/TR/webgpu/#dom-gpushadermodule-getcompilationinfo).
+
+This allows you to get more structured information about compilation errors, warnings and info:
+```rust
+...
+let lighting_shader = ctx.device.create_shader_module(include_wgsl!("lighting.wgsl"));
+let compilation_info = lighting_shader.get_compilation_info().await;
+for message in compilation_info
+    .messages
+    .iter()
+    .filter(|m| m.message_type == wgpu::CompilationMessageType::Error)
+{
+    let line = message.location.map(|l| l.line_number).unwrap_or(1);
+    println!("Compile error at line {line}");
+}
+```
+
+By @stefnotch in [#5410](https://github.com/gfx-rs/wgpu/pull/5410)
+
 
 #### Wgsl const evaluation for many more built-ins
 
@@ -125,6 +146,7 @@ By @atlv24 and @cwfitzgerald in [#5154](https://github.com/gfx-rs/wgpu/pull/5154
   ```
 - Breaking change: [`wgpu_core::pipeline::ProgrammableStageDescriptor`](https://docs.rs/wgpu-core/latest/wgpu_core/pipeline/struct.ProgrammableStageDescriptor.html#structfield.entry_point) is now optional. By @ErichDonGubler in [#5305](https://github.com/gfx-rs/wgpu/pull/5305).
 - `Features::downlevel{_webgl2,}_features` was made const by @MultisampledNight in [#5343](https://github.com/gfx-rs/wgpu/pull/5343)
+- Breaking change: [`wgpu_core::pipeline::ShaderError`](https://docs.rs/wgpu-core/latest/wgpu_core/pipeline/struct.ShaderError.html) has been moved to `naga`. By @stefnotch in [#5410](https://github.com/gfx-rs/wgpu/pull/5410)
 - More as_hal methods and improvements by @JMS55 in [#5452](https://github.com/gfx-rs/wgpu/pull/5452)
   - Added `wgpu::CommandEncoder::as_hal_mut`
   - Added `wgpu::TextureView::as_hal`
@@ -171,7 +193,7 @@ By @atlv24 and @cwfitzgerald in [#5154](https://github.com/gfx-rs/wgpu/pull/5154
 
 - Improved `wgpu_hal` documentation. By @jimblandy in [#5516](https://github.com/gfx-rs/wgpu/pull/5516), [#5524](https://github.com/gfx-rs/wgpu/pull/5524), [#5562](https://github.com/gfx-rs/wgpu/pull/5562), [#5563](https://github.com/gfx-rs/wgpu/pull/5563), [#5566](https://github.com/gfx-rs/wgpu/pull/5566), [#5617](https://github.com/gfx-rs/wgpu/pull/5617), [#5618](https://github.com/gfx-rs/wgpu/pull/5618)
 - Add mention of primitive restart in the description of `PrimitiveState::strip_index_format`. By @cpsdqs in [#5350](https://github.com/gfx-rs/wgpu/pull/5350)
-- Document precise behaviour of `SourceLocation`. By @stefnotch in [#5386](https://github.com/gfx-rs/wgpu/pull/5386)
+- Document and tweak precise behaviour of `SourceLocation`. By @stefnotch in [#5386](https://github.com/gfx-rs/wgpu/pull/5386) and [#5410](https://github.com/gfx-rs/wgpu/pull/5410)
 - Give short example of WGSL `push_constant` syntax. By @waywardmonkeys in [#5393](https://github.com/gfx-rs/wgpu/pull/5393)
 - Fix incorrect documentation of `Limits::max_compute_workgroup_storage_size` default value. By @atlv24 in [#5601](https://github.com/gfx-rs/wgpu/pull/5601)
 

Cargo.lock

@@ -0,0 +1,74 @@
+use std::{error::Error, fmt};
+
+#[derive(Clone, Debug)]
+pub struct ShaderError<E> {
+    /// The source code of the shader.
+    pub source: String,
+    pub label: Option<String>,
+    pub inner: Box<E>,
+}
+
+#[cfg(feature = "wgsl-in")]
+impl fmt::Display for ShaderError<crate::front::wgsl::ParseError> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let label = self.label.as_deref().unwrap_or_default();
+        let string = self.inner.emit_to_string(&self.source);
+        write!(f, "\nShader '{label}' parsing {string}")
+    }
+}
+#[cfg(feature = "glsl-in")]
+impl fmt::Display for ShaderError<crate::front::glsl::ParseErrors> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let label = self.label.as_deref().unwrap_or_default();
+        let string = self.inner.emit_to_string(&self.source);
+        write!(f, "\nShader '{label}' parsing {string}")
+    }
+}
+#[cfg(feature = "spv-in")]
+impl fmt::Display for ShaderError<crate::front::spv::Error> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let label = self.label.as_deref().unwrap_or_default();
+        let string = self.inner.emit_to_string(&self.source);
+        write!(f, "\nShader '{label}' parsing {string}")
+    }
+}
+impl fmt::Display for ShaderError<crate::WithSpan<crate::valid::ValidationError>> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        use codespan_reporting::{
+            diagnostic::{Diagnostic, Label},
+            files::SimpleFile,
+            term,
+        };
+
+        let label = self.label.as_deref().unwrap_or_default();
+        let files = SimpleFile::new(label, &self.source);
+        let config = term::Config::default();
+        let mut writer = term::termcolor::NoColor::new(Vec::new());
+
+        let diagnostic = Diagnostic::error().with_labels(
+            self.inner
+                .spans()
+                .map(|&(span, ref desc)| {
+                    Label::primary((), span.to_range().unwrap()).with_message(desc.to_owned())
+                })
+                .collect(),
+        );
+
+        term::emit(&mut writer, &config, &files, &diagnostic).expect("cannot write error");
+
+        write!(
+            f,
+            "\nShader validation {}",
+            String::from_utf8_lossy(&writer.into_inner())
+        )
+    }
+}
+impl<E> Error for ShaderError<E>
+where
+    ShaderError<E>: fmt::Display,
+    E: Error + 'static,
+{
+    fn source(&self) -> Option<&(dyn Error + 'static)> {
+        Some(&self.inner)
+    }
+}

naga/src/error.rs

@@ -1,4 +1,5 @@
 use super::token::TokenValue;
+use crate::SourceLocation;
 use crate::{proc::ConstantEvaluatorError, Span};
 use codespan_reporting::diagnostic::{Diagnostic, Label};
 use codespan_reporting::files::SimpleFile;
@@ -137,14 +138,21 @@ pub struct Error {
     pub meta: Span,
 }
 
+impl Error {
+    /// Returns a [`SourceLocation`] for the error message.
+    pub fn location(&self, source: &str) -> Option<SourceLocation> {
+        Some(self.meta.location(source))
+    }
+}
+
 /// A collection of errors returned during shader parsing.
 #[derive(Clone, Debug)]
 #[cfg_attr(test, derive(PartialEq))]
-pub struct ParseError {
+pub struct ParseErrors {
     pub errors: Vec<Error>,
 }
 
-impl ParseError {
+impl ParseErrors {
     pub fn emit_to_writer(&self, writer: &mut impl WriteColor, source: &str) {
         self.emit_to_writer_with_path(writer, source, "glsl");
     }
@@ -172,19 +180,19 @@ impl ParseError {
     }
 }
 
-impl std::fmt::Display for ParseError {
+impl std::fmt::Display for ParseErrors {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
         self.errors.iter().try_for_each(|e| write!(f, "{e:?}"))
     }
 }
 
-impl std::error::Error for ParseError {
+impl std::error::Error for ParseErrors {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         None
     }
 }
 
-impl From<Vec<Error>> for ParseError {
+impl From<Vec<Error>> for ParseErrors {
     fn from(errors: Vec<Error>) -> Self {
         Self { errors }
     }

naga/src/front/glsl/error.rs

@@ -13,7 +13,7 @@ To begin, take a look at the documentation for the [`Frontend`].
 */
 
 pub use ast::{Precision, Profile};
-pub use error::{Error, ErrorKind, ExpectedToken, ParseError};
+pub use error::{Error, ErrorKind, ExpectedToken, ParseErrors};
 pub use token::TokenValue;
 
 use crate::{proc::Layouter, FastHashMap, FastHashSet, Handle, Module, ShaderStage, Span, Type};
@@ -196,7 +196,7 @@ impl Frontend {
         &mut self,
         options: &Options,
         source: &str,
-    ) -> std::result::Result<Module, ParseError> {
+    ) -> std::result::Result<Module, ParseErrors> {
         self.reset(options.stage);
 
         let lexer = lex::Lexer::new(source, &options.defines);

naga/src/front/glsl/mod.rs

@@ -1,7 +1,7 @@
 use super::{
     ast::Profile,
     error::ExpectedToken,
-    error::{Error, ErrorKind, ParseError},
+    error::{Error, ErrorKind, ParseErrors},
     token::TokenValue,
     Frontend, Options, Span,
 };
@@ -21,7 +21,7 @@ fn version() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::InvalidVersion(99000),
                 meta: Span::new(9, 14)
@@ -37,7 +37,7 @@ fn version() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::InvalidVersion(449),
                 meta: Span::new(9, 12)
@@ -53,7 +53,7 @@ fn version() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::InvalidProfile("smart".into()),
                 meta: Span::new(13, 18),
@@ -69,7 +69,7 @@ fn version() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![
                 Error {
                     kind: ErrorKind::PreprocessorError(PreprocessorError::UnexpectedHash,),
@@ -455,7 +455,7 @@ fn functions() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::SemanticError("Function already defined".into()),
                 meta: Span::new(134, 152),
@@ -634,7 +634,7 @@ fn implicit_conversions() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::SemanticError("Unknown function \'test\'".into()),
                 meta: Span::new(156, 165),
@@ -658,7 +658,7 @@ fn implicit_conversions() {
             )
             .err()
             .unwrap(),
-        ParseError {
+        ParseErrors {
             errors: vec![Error {
                 kind: ErrorKind::SemanticError("Ambiguous best function for \'test\'".into()),
                 meta: Span::new(158, 165),

naga/src/front/glsl/parser_tests.rs

@@ -5,7 +5,7 @@ use codespan_reporting::files::SimpleFile;
 use codespan_reporting::term;
 use termcolor::{NoColor, WriteColor};
 
-#[derive(Debug, thiserror::Error)]
+#[derive(Clone, Debug, thiserror::Error)]
 pub enum Error {
     #[error("invalid header")]
     InvalidHeader,

naga/src/front/spv/error.rs

@@ -13,6 +13,7 @@ use thiserror::Error;
 #[derive(Clone, Debug)]
 pub struct ParseError {
     message: String,
+    // The first span should be the primary span, and the other ones should be complementary.
     labels: Vec<(Span, Cow<'static, str>)>,
     notes: Vec<String>,
 }

naga/src/front/wgsl/error.rs

@@ -274,6 +274,7 @@ pub mod back;
 mod block;
 #[cfg(feature = "compact")]
 pub mod compact;
+pub mod error;
 pub mod front;
 pub mod keywords;
 pub mod proc;

naga/src/lib.rs

@@ -72,8 +72,8 @@ impl Span {
     pub fn location(&self, source: &str) -> SourceLocation {
         let prefix = &source[..self.start as usize];
         let line_number = prefix.matches('\n').count() as u32 + 1;
-        let line_start = prefix.rfind('\n').map(|pos| pos + 1).unwrap_or(0);
-        let line_position = source[line_start..self.start as usize].chars().count() as u32 + 1;
+        let line_start = prefix.rfind('\n').map(|pos| pos + 1).unwrap_or(0) as u32;
+        let line_position = self.start - line_start + 1;
 
         SourceLocation {
             line_number,
@@ -107,14 +107,14 @@ impl std::ops::Index<Span> for str {
 /// Roughly corresponds to the positional members of [`GPUCompilationMessage`][gcm] from
 /// the WebGPU specification, except
 /// - `offset` and `length` are in bytes (UTF-8 code units), instead of UTF-16 code units.
-/// - `line_position` counts entire Unicode code points, instead of UTF-16 code units.
+/// - `line_position` is in bytes (UTF-8 code units), instead of UTF-16 code units.
 ///
 /// [gcm]: https://www.w3.org/TR/webgpu/#gpucompilationmessage
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct SourceLocation {
     /// 1-based line number.
     pub line_number: u32,
-    /// 1-based column of the start of this span, counted in Unicode code points.
+    /// 1-based column in code units (in bytes) of the start of the span.
     pub line_position: u32,
     /// 0-based Offset in code units (in bytes) of the start of the span.
     pub offset: u32,