Rollup merge of rust-lang#109984 - scottmcm:less-float, r=Nilstrieb

Remove f32 & f64 from MemDecoder/MemEncoder

r? ```@Nilstrieb```
since they said (maybe joked) on discord that it's a bug if the compiler uses f32 anywhere 🙃

Author: matthiaskrgr

Diff for: compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -112,8 +112,6 @@ impl<'a, 'tcx> Encoder for EncodeContext<'a, 'tcx> {
         emit_i8(i8);
 
         emit_bool(bool);
-        emit_f64(f64);
-        emit_f32(f32);
         emit_char(char);
         emit_str(&str);
         emit_raw_bytes(&[u8]);

Diff for: compiler/rustc_middle/src/ty/codec.rs

@@ -511,8 +511,6 @@ macro_rules! implement_ty_decoder {
                     read_isize -> isize;
 
                     read_bool -> bool;
-                    read_f64 -> f64;
-                    read_f32 -> f32;
                     read_char -> char;
                     read_str -> &str;
                 }

Diff for: compiler/rustc_query_impl/src/on_disk_cache.rs

@@ -1046,8 +1046,6 @@ impl<'a, 'tcx> Encoder for CacheEncoder<'a, 'tcx> {
         emit_i8(i8);
 
         emit_bool(bool);
-        emit_f64(f64);
-        emit_f32(f32);
         emit_char(char);
         emit_str(&str);
         emit_raw_bytes(&[u8]);

Diff for: compiler/rustc_serialize/src/opaque.rs

@@ -122,18 +122,6 @@ impl Encoder for MemEncoder {
         self.emit_u8(if v { 1 } else { 0 });
     }
 
-    #[inline]
-    fn emit_f64(&mut self, v: f64) {
-        let as_u64: u64 = v.to_bits();
-        self.emit_u64(as_u64);
-    }
-
-    #[inline]
-    fn emit_f32(&mut self, v: f32) {
-        let as_u32: u32 = v.to_bits();
-        self.emit_u32(as_u32);
-    }
-
     #[inline]
     fn emit_char(&mut self, v: char) {
         self.emit_u32(v as u32);
@@ -500,18 +488,6 @@ impl Encoder for FileEncoder {
         self.emit_u8(if v { 1 } else { 0 });
     }
 
-    #[inline]
-    fn emit_f64(&mut self, v: f64) {
-        let as_u64: u64 = v.to_bits();
-        self.emit_u64(as_u64);
-    }
-
-    #[inline]
-    fn emit_f32(&mut self, v: f32) {
-        let as_u32: u32 = v.to_bits();
-        self.emit_u32(as_u32);
-    }
-
     #[inline]
     fn emit_char(&mut self, v: char) {
         self.emit_u32(v as u32);
@@ -642,18 +618,6 @@ impl<'a> Decoder for MemDecoder<'a> {
         value != 0
     }
 
-    #[inline]
-    fn read_f64(&mut self) -> f64 {
-        let bits = self.read_u64();
-        f64::from_bits(bits)
-    }
-
-    #[inline]
-    fn read_f32(&mut self) -> f32 {
-        let bits = self.read_u32();
-        f32::from_bits(bits)
-    }
-
     #[inline]
     fn read_char(&mut self) -> char {
         let bits = self.read_u32();

Diff for: compiler/rustc_serialize/src/serialize.rs

@@ -22,6 +22,11 @@ use std::sync::Arc;
 /// be processed or ignored, whichever is appropriate. Then they should provide
 /// a `finish` method that finishes up encoding. If the encoder is fallible,
 /// `finish` should return a `Result` that indicates success or failure.
+///
+/// This current does not support `f32` nor `f64`, as they're not needed in any
+/// serialized data structures. That could be changed, but consider whether it
+/// really makes sense to store floating-point values at all.
+/// (If you need it, revert <https://github.com/rust-lang/rust/pull/109984>.)
 pub trait Encoder {
     // Primitive types:
     fn emit_usize(&mut self, v: usize);
@@ -37,8 +42,6 @@ pub trait Encoder {
     fn emit_i16(&mut self, v: i16);
     fn emit_i8(&mut self, v: i8);
     fn emit_bool(&mut self, v: bool);
-    fn emit_f64(&mut self, v: f64);
-    fn emit_f32(&mut self, v: f32);
     fn emit_char(&mut self, v: char);
     fn emit_str(&mut self, v: &str);
     fn emit_raw_bytes(&mut self, s: &[u8]);
@@ -58,6 +61,11 @@ pub trait Encoder {
 // top-level invocation would also just panic on failure. Switching to
 // infallibility made things faster and lots of code a little simpler and more
 // concise.
+///
+/// This current does not support `f32` nor `f64`, as they're not needed in any
+/// serialized data structures. That could be changed, but consider whether it
+/// really makes sense to store floating-point values at all.
+/// (If you need it, revert <https://github.com/rust-lang/rust/pull/109984>.)
 pub trait Decoder {
     // Primitive types:
     fn read_usize(&mut self) -> usize;
@@ -73,8 +81,6 @@ pub trait Decoder {
     fn read_i16(&mut self) -> i16;
     fn read_i8(&mut self) -> i8;
     fn read_bool(&mut self) -> bool;
-    fn read_f64(&mut self) -> f64;
-    fn read_f32(&mut self) -> f32;
     fn read_char(&mut self) -> char;
     fn read_str(&mut self) -> &str;
     fn read_raw_bytes(&mut self, len: usize) -> &[u8];
@@ -143,8 +149,6 @@ direct_serialize_impls! {
     i64 emit_i64 read_i64,
     i128 emit_i128 read_i128,
 
-    f32 emit_f32 read_f32,
-    f64 emit_f64 read_f64,
     bool emit_bool read_bool,
     char emit_char read_char
 }

Diff for: compiler/rustc_serialize/tests/opaque.rs

@@ -22,8 +22,6 @@ struct Struct {
 
     l: char,
     m: String,
-    n: f32,
-    o: f64,
     p: bool,
     q: Option<u32>,
 }
@@ -119,24 +117,6 @@ fn test_bool() {
     check_round_trip(vec![false, true, true, false, false]);
 }
 
-#[test]
-fn test_f32() {
-    let mut vec = vec![];
-    for i in -100..100 {
-        vec.push((i as f32) / 3.0);
-    }
-    check_round_trip(vec);
-}
-
-#[test]
-fn test_f64() {
-    let mut vec = vec![];
-    for i in -100..100 {
-        vec.push((i as f64) / 3.0);
-    }
-    check_round_trip(vec);
-}
-
 #[test]
 fn test_char() {
     let vec = vec!['a', 'b', 'c', 'd', 'A', 'X', ' ', '#', 'Ö', 'Ä', 'µ', '€'];
@@ -200,8 +180,6 @@ fn test_struct() {
 
         l: 'x',
         m: "abc".to_string(),
-        n: 20.5,
-        o: 21.5,
         p: false,
         q: None,
     }]);
@@ -222,8 +200,6 @@ fn test_struct() {
 
         l: 'y',
         m: "def".to_string(),
-        n: -20.5,
-        o: -21.5,
         p: true,
         q: Some(1234567),
     }]);
@@ -232,15 +208,15 @@ fn test_struct() {
 #[derive(PartialEq, Clone, Debug, Encodable, Decodable)]
 enum Enum {
     Variant1,
-    Variant2(usize, f32),
+    Variant2(usize, u32),
     Variant3 { a: i32, b: char, c: bool },
 }
 
 #[test]
 fn test_enum() {
     check_round_trip(vec![
         Enum::Variant1,
-        Enum::Variant2(1, 2.5),
+        Enum::Variant2(1, 25),
         Enum::Variant3 { a: 3, b: 'b', c: false },
         Enum::Variant3 { a: -4, b: 'f', c: true },
     ]);
@@ -269,8 +245,8 @@ fn test_hash_map() {
 
 #[test]
 fn test_tuples() {
-    check_round_trip(vec![('x', (), false, 0.5f32)]);
-    check_round_trip(vec![(9i8, 10u16, 1.5f64)]);
+    check_round_trip(vec![('x', (), false, 5u32)]);
+    check_round_trip(vec![(9i8, 10u16, 15i64)]);
     check_round_trip(vec![(-12i16, 11u8, 12usize)]);
     check_round_trip(vec![(1234567isize, 100000000000000u64, 99999999999999i64)]);
     check_round_trip(vec![(String::new(), "some string".to_string())]);