rustup: lockfile fix, and a patch for f16/f128 float math

run-test.sh

@@ -33,7 +33,7 @@ rm -f library
 ln -s "$MIRI_LIB_SRC" library
 
 # use the rust-src lockfile
-cp "$MIRI_LIB_SRC/../Cargo.lock" Cargo.lock
+cp "$MIRI_LIB_SRC/Cargo.lock" Cargo.lock
 
 # This ensures that the "core" crate being built as part of `cargo miri test`
 # is just a re-export of the sysroot crate, so we don't get duplicate lang items.

rust-src.diff

@@ -0,0 +1,78 @@
+diff --git a/library/std/build.rs b/library/std/build.rs
+index 18ca7b512a9..35a5977b6eb 100644
+--- a/library/std/build.rs
++++ b/library/std/build.rs
+@@ -11,6 +11,7 @@ fn main() {
+         .expect("CARGO_CFG_TARGET_POINTER_WIDTH was not set")
+         .parse()
+         .unwrap();
++    let is_miri = env::var_os("CARGO_CFG_MIRI").is_some();
+
+     println!("cargo:rustc-check-cfg=cfg(netbsd10)");
+     if target_os == "netbsd" && env::var("RUSTC_STD_NETBSD10").is_ok() {
+@@ -91,6 +92,8 @@ fn main() {
+     println!("cargo:rustc-check-cfg=cfg(reliable_f128_math)");
+
+     let has_reliable_f16 = match (target_arch.as_str(), target_os.as_str()) {
++        // We can always enable these in Miri as that is not affected by codegen bugs.
++        _ if is_miri => true,
+         // Selection failure until recent LLVM <https://github.com/llvm/llvm-project/issues/93894>
+         // FIXME(llvm19): can probably be removed at the version bump
+         ("loongarch64", _) => false,
+@@ -118,6 +121,8 @@ fn main() {
+     };
+
+     let has_reliable_f128 = match (target_arch.as_str(), target_os.as_str()) {
++        // We can always enable these in Miri as that is not affected by codegen bugs.
++        _ if is_miri => true,
+         // Unsupported <https://github.com/llvm/llvm-project/issues/94434>
+         ("arm64ec", _) => false,
+         // ABI and precision bugs <https://github.com/rust-lang/rust/issues/125109>
+@@ -141,6 +146,8 @@ fn main() {
+     // LLVM is currenlty adding missing routines, <https://github.com/llvm/llvm-project/issues/93566>
+     let has_reliable_f16_math = has_reliable_f16
+         && match (target_arch.as_str(), target_os.as_str()) {
++            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
++            _ if is_miri => false,
+             // Currently nothing special. Hooray!
+             // This will change as platforms gain better better support for standard ops but math
+             // lags behind.
+@@ -149,6 +156,8 @@ fn main() {
+
+     let has_reliable_f128_math = has_reliable_f128
+         && match (target_arch.as_str(), target_os.as_str()) {
++            // FIXME: Disabled on Miri as the intrinsics are not implemented yet.
++            _ if is_miri => false,
+             // LLVM lowers `fp128` math to `long double` symbols even on platforms where
+             // `long double` is not IEEE binary128. See
+             // <https://github.com/llvm/llvm-project/issues/44744>.
+diff --git a/library/std/src/f16/tests.rs b/library/std/src/f16/tests.rs
+index 50504e7ffd9..684ee3f3855 100644
+--- a/library/std/src/f16/tests.rs
++++ b/library/std/src/f16/tests.rs
+@@ -4,20 +4,20 @@
+ use crate::f16::consts;
+ use crate::num::{FpCategory as Fp, *};
+
+-/// Tolerance for results on the order of 10.0e-2;
+-#[cfg(reliable_f16_math)]
++/// Tolerance for results on the order of 10.0e-2
++#[allow(unused)]
+ const TOL_N2: f16 = 0.0001;
+
+ /// Tolerance for results on the order of 10.0e+0
+-#[cfg(reliable_f16_math)]
++#[allow(unused)]
+ const TOL_0: f16 = 0.01;
+
+ /// Tolerance for results on the order of 10.0e+2
+-#[cfg(reliable_f16_math)]
++#[allow(unused)]
+ const TOL_P2: f16 = 0.5;
+
+ /// Tolerance for results on the order of 10.0e+4
+-#[cfg(reliable_f16_math)]
++#[allow(unused)]
+ const TOL_P4: f16 = 10.0;
+
+ /// Smallest number

rust-version

@@ -1 +1 @@
-nightly-2024-08-05
+nightly-2024-08-08