[naga wgsl] Let unary operators accept and produce abstract types.

Fixes gfx-rs#4445. Fixes gfx-rs#4492. Fixes gfx-rs#4435.
jimblandy · Dec 13, 2023 · c4abfe7 · c4abfe7
1 parent c4b4387
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -68,7 +68,7 @@ This feature allowed you to call `global_id` on any wgpu opaque handle to get a
 
 #### Naga
 
-- Naga's WGSL front end now allows binary operators to produce values with abstract types, rather than concretizing thir operands. By @jimblandy in [#4850](https://github.com/gfx-rs/wgpu/pull/4850).
+- Naga's WGSL front end now allows operators to produce values with abstract types, rather than concretizing thir operands. By @jimblandy in [#4850](https://github.com/gfx-rs/wgpu/pull/4850) and [#4870](https://github.com/gfx-rs/wgpu/pull/4870).
 
 - Naga's WGSL front and back ends now have experimental support for 64-bit floating-point literals: `1.0lf` denotes an `f64` value. There has been experimental support for an `f64` type for a while, but until now there was no syntax for writing literals with that type. As before, Naga module validation rejects `f64` values unless `naga::valid::Capabilities::FLOAT64` is requested. By @jimblandy in [#4747](https://github.com/gfx-rs/wgpu/pull/4747).
 

diff --git a/naga/src/back/wgsl/writer.rs b/naga/src/back/wgsl/writer.rs
@@ -1090,7 +1090,16 @@ impl<W: Write> Writer<W> {
             Expression::Literal(literal) => match literal {
                 crate::Literal::F32(value) => write!(self.out, "{}f", value)?,
                 crate::Literal::U32(value) => write!(self.out, "{}u", value)?,
-                crate::Literal::I32(value) => write!(self.out, "{}i", value)?,
+                crate::Literal::I32(value) => {
+                    // `-2147483648i` is not valid WGSL. The most negative `i32`
+                    // value can only be expressed in WGSL using AbstractInt and
+                    // a unary negation operator.
+                    if value == i32::MIN {
+                        write!(self.out, "i32(-2147483648)")?;
+                    } else {
+                        write!(self.out, "{}i", value)?;
+                    }
+                }
                 crate::Literal::Bool(value) => write!(self.out, "{}", value)?,
                 crate::Literal::F64(value) => write!(self.out, "{:?}lf", value)?,
                 crate::Literal::I64(_) => {

diff --git a/naga/src/front/wgsl/lower/mod.rs b/naga/src/front/wgsl/lower/mod.rs
@@ -1574,7 +1574,7 @@ impl<'source, 'temp> Lowerer<'source, 'temp> {
                 return Ok(Typed::Plain(handle));
             }
             ast::Expression::Unary { op, expr } => {
-                let expr = self.expression(expr, ctx)?;
+                let expr = self.expression_for_abstract(expr, ctx)?;
                 Typed::Plain(crate::Expression::Unary { op, expr })
             }
             ast::Expression::AddrOf(expr) => {

diff --git a/naga/src/front/wgsl/parse/lexer.rs b/naga/src/front/wgsl/parse/lexer.rs
@@ -117,7 +117,6 @@ fn consume_token(input: &str, generic: bool) -> (Token<'_>, &str) {
             let og_chars = chars.as_str();
             match chars.next() {
                 Some('>') => (Token::Arrow, chars.as_str()),
-                Some('0'..='9' | '.') => consume_number(input),
                 Some('-') => (Token::DecrementOperation, chars.as_str()),
                 Some('=') => (Token::AssignmentOperation(cur), chars.as_str()),
                 _ => (Token::Operation(cur), og_chars),
@@ -496,44 +495,60 @@ fn test_numbers() {
 
     // MIN / MAX //
 
-    // min / max decimal signed integer
+    // min / max decimal integer
     sub_test(
-        "-2147483648i 2147483647i -2147483649i 2147483648i",
+        "0i 2147483647i 2147483648i",
         &[
-            Token::Number(Ok(Number::I32(i32::MIN))),
+            Token::Number(Ok(Number::I32(0))),
             Token::Number(Ok(Number::I32(i32::MAX))),
             Token::Number(Err(NumberError::NotRepresentable)),
-            Token::Number(Err(NumberError::NotRepresentable)),
         ],
     );
     // min / max decimal unsigned integer
     sub_test(
-        "0u 4294967295u -1u 4294967296u",
+        "0u 4294967295u 4294967296u",
         &[
             Token::Number(Ok(Number::U32(u32::MIN))),
             Token::Number(Ok(Number::U32(u32::MAX))),
             Token::Number(Err(NumberError::NotRepresentable)),
-            Token::Number(Err(NumberError::NotRepresentable)),
         ],
     );
 
     // min / max hexadecimal signed integer
     sub_test(
-        "-0x80000000i 0x7FFFFFFFi -0x80000001i 0x80000000i",
+        "0x0i 0x7FFFFFFFi 0x80000000i",
         &[
-            Token::Number(Ok(Number::I32(i32::MIN))),
+            Token::Number(Ok(Number::I32(0))),
             Token::Number(Ok(Number::I32(i32::MAX))),
             Token::Number(Err(NumberError::NotRepresentable)),
-            Token::Number(Err(NumberError::NotRepresentable)),
         ],
     );
     // min / max hexadecimal unsigned integer
     sub_test(
-        "0x0u 0xFFFFFFFFu -0x1u 0x100000000u",
+        "0x0u 0xFFFFFFFFu 0x100000000u",
         &[
             Token::Number(Ok(Number::U32(u32::MIN))),
             Token::Number(Ok(Number::U32(u32::MAX))),
             Token::Number(Err(NumberError::NotRepresentable)),
+        ],
+    );
+
+    // min/max decimal abstract int
+    sub_test(
+        "0 9223372036854775807 9223372036854775808",
+        &[
+            Token::Number(Ok(Number::AbstractInt(0))),
+            Token::Number(Ok(Number::AbstractInt(i64::MAX))),
+            Token::Number(Err(NumberError::NotRepresentable)),
+        ],
+    );
+
+    // min/max hexadecimal abstract int
+    sub_test(
+        "0 0x7fffffffffffffff 0x8000000000000000",
+        &[
+            Token::Number(Ok(Number::AbstractInt(0))),
+            Token::Number(Ok(Number::AbstractInt(i64::MAX))),
             Token::Number(Err(NumberError::NotRepresentable)),
         ],
     );
@@ -548,77 +563,43 @@ fn test_numbers() {
     const LARGEST_F32_LESS_THAN_ONE: f32 = 0.99999994;
     /// ≈ 1 + 2^−23
     const SMALLEST_F32_LARGER_THAN_ONE: f32 = 1.0000001;
-    /// ≈ -(2^127 * (2 − 2^−23))
-    const SMALLEST_NORMAL_F32: f32 = f32::MIN;
     /// ≈ 2^127 * (2 − 2^−23)
     const LARGEST_NORMAL_F32: f32 = f32::MAX;
 
     // decimal floating point
     sub_test(
-        "1e-45f 1.1754942e-38f 1.17549435e-38f 0.99999994f 1.0000001f -3.40282347e+38f 3.40282347e+38f",
+        "1e-45f 1.1754942e-38f 1.17549435e-38f 0.99999994f 1.0000001f 3.40282347e+38f",
         &[
-            Token::Number(Ok(Number::F32(
-                SMALLEST_POSITIVE_SUBNORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_SUBNORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_POSITIVE_NORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_F32_LESS_THAN_ONE,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_F32_LARGER_THAN_ONE,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_NORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_NORMAL_F32,
-            ))),
+            Token::Number(Ok(Number::F32(SMALLEST_POSITIVE_SUBNORMAL_F32))),
+            Token::Number(Ok(Number::F32(LARGEST_SUBNORMAL_F32))),
+            Token::Number(Ok(Number::F32(SMALLEST_POSITIVE_NORMAL_F32))),
+            Token::Number(Ok(Number::F32(LARGEST_F32_LESS_THAN_ONE))),
+            Token::Number(Ok(Number::F32(SMALLEST_F32_LARGER_THAN_ONE))),
+            Token::Number(Ok(Number::F32(LARGEST_NORMAL_F32))),
         ],
     );
     sub_test(
-        "-3.40282367e+38f 3.40282367e+38f",
+        "3.40282367e+38f",
         &[
-            Token::Number(Err(NumberError::NotRepresentable)), // ≈ -2^128
             Token::Number(Err(NumberError::NotRepresentable)), // ≈ 2^128
         ],
     );
 
     // hexadecimal floating point
     sub_test(
-        "0x1p-149f 0x7FFFFFp-149f 0x1p-126f 0xFFFFFFp-24f 0x800001p-23f -0xFFFFFFp+104f 0xFFFFFFp+104f",
+        "0x1p-149f 0x7FFFFFp-149f 0x1p-126f 0xFFFFFFp-24f 0x800001p-23f 0xFFFFFFp+104f",
         &[
-            Token::Number(Ok(Number::F32(
-                SMALLEST_POSITIVE_SUBNORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_SUBNORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_POSITIVE_NORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_F32_LESS_THAN_ONE,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_F32_LARGER_THAN_ONE,
-            ))),
-            Token::Number(Ok(Number::F32(
-                SMALLEST_NORMAL_F32,
-            ))),
-            Token::Number(Ok(Number::F32(
-                LARGEST_NORMAL_F32,
-            ))),
+            Token::Number(Ok(Number::F32(SMALLEST_POSITIVE_SUBNORMAL_F32))),
+            Token::Number(Ok(Number::F32(LARGEST_SUBNORMAL_F32))),
+            Token::Number(Ok(Number::F32(SMALLEST_POSITIVE_NORMAL_F32))),
+            Token::Number(Ok(Number::F32(LARGEST_F32_LESS_THAN_ONE))),
+            Token::Number(Ok(Number::F32(SMALLEST_F32_LARGER_THAN_ONE))),
+            Token::Number(Ok(Number::F32(LARGEST_NORMAL_F32))),
         ],
     );
     sub_test(
-        "-0x1p128f 0x1p128f 0x1.000001p0f",
+        "0x1p128f 0x1.000001p0f",
         &[
-            Token::Number(Err(NumberError::NotRepresentable)), // = -2^128
             Token::Number(Err(NumberError::NotRepresentable)), // = 2^128
             Token::Number(Err(NumberError::NotRepresentable)),
         ],

diff --git a/naga/src/front/wgsl/parse/number.rs b/naga/src/front/wgsl/parse/number.rs
@@ -1,5 +1,3 @@
-use std::borrow::Cow;
-
 use crate::front::wgsl::error::NumberError;
 use crate::front::wgsl::parse::lexer::Token;
 
@@ -20,8 +18,6 @@ pub enum Number {
     F64(f64),
 }
 
-// TODO: when implementing Creation-Time Expressions, remove the ability to match the minus sign
-
 pub(in crate::front::wgsl) fn consume_number(input: &str) -> (Token<'_>, &str) {
     let (result, rest) = parse(input);
     (Token::Number(result), rest)
@@ -64,7 +60,9 @@ enum FloatKind {
 // | / 0[xX][0-9a-fA-F]+                         [pP][+-]?[0-9]+        [fh]?   /
 
 // You could visualize the regex below via https://debuggex.com to get a rough idea what `parse` is doing
-// -?(?:0[xX](?:([0-9a-fA-F]+\.[0-9a-fA-F]*|[0-9a-fA-F]*\.[0-9a-fA-F]+)(?:([pP][+-]?[0-9]+)([fh]?))?|([0-9a-fA-F]+)([pP][+-]?[0-9]+)([fh]?)|([0-9a-fA-F]+)([iu]?))|((?:[0-9]+[eE][+-]?[0-9]+|(?:[0-9]+\.[0-9]*|[0-9]*\.[0-9]+)(?:[eE][+-]?[0-9]+)?))([fh]?)|((?:[0-9]|[1-9][0-9]+))([iufh]?))
+// (?:0[xX](?:([0-9a-fA-F]+\.[0-9a-fA-F]*|[0-9a-fA-F]*\.[0-9a-fA-F]+)(?:([pP][+-]?[0-9]+)([fh]?))?|([0-9a-fA-F]+)([pP][+-]?[0-9]+)([fh]?)|([0-9a-fA-F]+)([iu]?))|((?:[0-9]+[eE][+-]?[0-9]+|(?:[0-9]+\.[0-9]*|[0-9]*\.[0-9]+)(?:[eE][+-]?[0-9]+)?))([fh]?)|((?:[0-9]|[1-9][0-9]+))([iufh]?))
+
+// Leading signs are handled as unary operators.
 
 fn parse(input: &str) -> (Result<Number, NumberError>, &str) {
     /// returns `true` and consumes `X` bytes from the given byte buffer
@@ -152,8 +150,6 @@ fn parse(input: &str) -> (Result<Number, NumberError>, &str) {
 
     let general_extract = ExtractSubStr::start(input, bytes);
 
-    let is_negative = consume!(bytes, b'-');
-
     if consume!(bytes, b'0', b'x' | b'X') {
         let digits_extract = ExtractSubStr::start(input, bytes);
 
@@ -216,10 +212,7 @@ fn parse(input: &str) -> (Result<Number, NumberError>, &str) {
             } else {
                 let kind = consume_map!(bytes, [b'i' => IntKind::I32, b'u' => IntKind::U32]);
 
-                (
-                    parse_hex_int(is_negative, digits, kind),
-                    rest_to_str!(bytes),
-                )
+                (parse_hex_int(digits, kind), rest_to_str!(bytes))
             }
         }
     } else {
@@ -272,7 +265,7 @@ fn parse(input: &str) -> (Result<Number, NumberError>, &str) {
                     return (Err(NumberError::Invalid), rest_to_str!(bytes));
                 }
 
-                let digits_with_sign = general_extract.end(bytes);
+                let digits = general_extract.end(bytes);
 
                 let kind = consume_map!(bytes, [
                     b'i' => Kind::Int(IntKind::I32),
@@ -282,17 +275,14 @@ fn parse(input: &str) -> (Result<Number, NumberError>, &str) {
                     b'l', b'f' => Kind::Float(FloatKind::F64),
                 ]);
 
-                (
-                    parse_dec(is_negative, digits_with_sign, kind),
-                    rest_to_str!(bytes),
-                )
+                (parse_dec(digits, kind), rest_to_str!(bytes))
             }
         }
     }
 }
 
 fn parse_hex_float_missing_exponent(
-    // format: -?0[xX] ( [0-9a-fA-F]+\.[0-9a-fA-F]* | [0-9a-fA-F]*\.[0-9a-fA-F]+ )
+    // format: 0[xX] ( [0-9a-fA-F]+\.[0-9a-fA-F]* | [0-9a-fA-F]*\.[0-9a-fA-F]+ )
     significand: &str,
     kind: Option<FloatKind>,
 ) -> Result<Number, NumberError> {
@@ -301,7 +291,7 @@ fn parse_hex_float_missing_exponent(
 }
 
 fn parse_hex_float_missing_period(
-    // format: -?0[xX] [0-9a-fA-F]+
+    // format: 0[xX] [0-9a-fA-F]+
     significand: &str,
     // format: [pP][+-]?[0-9]+
     exponent: &str,
@@ -312,29 +302,22 @@ fn parse_hex_float_missing_period(
 }
 
 fn parse_hex_int(
-    is_negative: bool,
     // format: [0-9a-fA-F]+
     digits: &str,
     kind: Option<IntKind>,
 ) -> Result<Number, NumberError> {
-    let digits_with_sign = if is_negative {
-        Cow::Owned(format!("-{digits}"))
-    } else {
-        Cow::Borrowed(digits)
-    };
-    parse_int(&digits_with_sign, kind, 16, is_negative)
+    parse_int(digits, kind, 16)
 }
 
 fn parse_dec(
-    is_negative: bool,
-    // format: -? ( [0-9] | [1-9][0-9]+ )
-    digits_with_sign: &str,
+    // format: ( [0-9] | [1-9][0-9]+ )
+    digits: &str,
     kind: Option<Kind>,
 ) -> Result<Number, NumberError> {
     match kind {
-        None => parse_int(digits_with_sign, None, 10, is_negative),
-        Some(Kind::Int(kind)) => parse_int(digits_with_sign, Some(kind), 10, is_negative),
-        Some(Kind::Float(kind)) => parse_dec_float(digits_with_sign, Some(kind)),
+        None => parse_int(digits, None, 10),
+        Some(Kind::Int(kind)) => parse_int(digits, Some(kind), 10),
+        Some(Kind::Float(kind)) => parse_dec_float(digits, Some(kind)),
     }
 }
 
@@ -363,7 +346,7 @@ fn parse_dec(
 
 // Therefore we only check for overflow manually for decimal floating point literals
 
-// input format: -?0[xX] ( [0-9a-fA-F]+\.[0-9a-fA-F]* | [0-9a-fA-F]*\.[0-9a-fA-F]+ ) [pP][+-]?[0-9]+
+// input format: 0[xX] ( [0-9a-fA-F]+\.[0-9a-fA-F]* | [0-9a-fA-F]*\.[0-9a-fA-F]+ ) [pP][+-]?[0-9]+
 fn parse_hex_float(input: &str, kind: Option<FloatKind>) -> Result<Number, NumberError> {
     match kind {
         None => match hexf_parse::parse_hexf64(input, false) {
@@ -385,8 +368,8 @@ fn parse_hex_float(input: &str, kind: Option<FloatKind>) -> Result<Number, Numbe
     }
 }
 
-// input format: -? ( [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) ([eE][+-]?[0-9]+)?
-//             | -? [0-9]+ [eE][+-]?[0-9]+
+// input format: ( [0-9]+\.[0-9]* | [0-9]*\.[0-9]+ ) ([eE][+-]?[0-9]+)?
+//             | [0-9]+ [eE][+-]?[0-9]+
 fn parse_dec_float(input: &str, kind: Option<FloatKind>) -> Result<Number, NumberError> {
     match kind {
         None => {
@@ -411,12 +394,7 @@ fn parse_dec_float(input: &str, kind: Option<FloatKind>) -> Result<Number, Numbe
     }
 }
 
-fn parse_int(
-    input: &str,
-    kind: Option<IntKind>,
-    radix: u32,
-    is_negative: bool,
-) -> Result<Number, NumberError> {
+fn parse_int(input: &str, kind: Option<IntKind>, radix: u32) -> Result<Number, NumberError> {
     fn map_err(e: core::num::ParseIntError) -> NumberError {
         match *e.kind() {
             core::num::IntErrorKind::PosOverflow | core::num::IntErrorKind::NegOverflow => {
@@ -434,7 +412,6 @@ fn parse_int(
             Ok(num) => Ok(Number::I32(num)),
             Err(e) => Err(map_err(e)),
         },
-        Some(IntKind::U32) if is_negative => Err(NumberError::NotRepresentable),
         Some(IntKind::U32) => match u32::from_str_radix(input, radix) {
             Ok(num) => Ok(Number::U32(num)),
             Err(e) => Err(map_err(e)),

diff --git a/naga/src/proc/constant_evaluator.rs b/naga/src/proc/constant_evaluator.rs
@@ -1193,6 +1193,8 @@ impl<'a> ConstantEvaluator<'a> {
                 UnaryOperator::Negate => match value {
                     Literal::I32(v) => Literal::I32(-v),
                     Literal::F32(v) => Literal::F32(-v),
+                    Literal::AbstractInt(v) => Literal::AbstractInt(-v),
+                    Literal::AbstractFloat(v) => Literal::AbstractFloat(-v),
                     _ => return Err(ConstantEvaluatorError::InvalidUnaryOpArg),
                 },
                 UnaryOperator::LogicalNot => match value {
@@ -1202,6 +1204,7 @@ impl<'a> ConstantEvaluator<'a> {
                 UnaryOperator::BitwiseNot => match value {
                     Literal::I32(v) => Literal::I32(!v),
                     Literal::U32(v) => Literal::U32(!v),
+                    Literal::AbstractInt(v) => Literal::AbstractInt(!v),
                     _ => return Err(ConstantEvaluatorError::InvalidUnaryOpArg),
                 },
             }),