diff options
Diffstat (limited to 'src/tools/miri/src/intrinsics/math.rs')
| -rw-r--r-- | src/tools/miri/src/intrinsics/math.rs | 313 |
1 files changed, 313 insertions, 0 deletions
diff --git a/src/tools/miri/src/intrinsics/math.rs b/src/tools/miri/src/intrinsics/math.rs new file mode 100644 index 00000000000..b9c99f28594 --- /dev/null +++ b/src/tools/miri/src/intrinsics/math.rs @@ -0,0 +1,313 @@ +use rand::Rng; +use rustc_apfloat::{self, Float, FloatConvert, Round}; +use rustc_middle::mir; +use rustc_middle::ty::{self, FloatTy}; + +use self::helpers::{ToHost, ToSoft}; +use super::check_intrinsic_arg_count; +use crate::*; + +fn sqrt<'tcx, F: Float + FloatConvert<F> + Into<Scalar>>( + this: &mut MiriInterpCx<'tcx>, + args: &[OpTy<'tcx>], + dest: &MPlaceTy<'tcx>, +) -> InterpResult<'tcx> { + let [f] = check_intrinsic_arg_count(args)?; + let f = this.read_scalar(f)?; + let f: F = f.to_float()?; + // Sqrt is specified to be fully precise. + let res = math::sqrt(f); + let res = this.adjust_nan(res, &[f]); + this.write_scalar(res, dest) +} + +impl<'tcx> EvalContextExt<'tcx> for crate::MiriInterpCx<'tcx> {} +pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> { + fn emulate_math_intrinsic( + &mut self, + intrinsic_name: &str, + _generic_args: ty::GenericArgsRef<'tcx>, + args: &[OpTy<'tcx>], + dest: &MPlaceTy<'tcx>, + ) -> InterpResult<'tcx, EmulateItemResult> { + let this = self.eval_context_mut(); + + match intrinsic_name { + // Operations we can do with soft-floats. + "sqrtf16" => sqrt::<rustc_apfloat::ieee::Half>(this, args, dest)?, + "sqrtf32" => sqrt::<rustc_apfloat::ieee::Single>(this, args, dest)?, + "sqrtf64" => sqrt::<rustc_apfloat::ieee::Double>(this, args, dest)?, + "sqrtf128" => sqrt::<rustc_apfloat::ieee::Quad>(this, args, dest)?, + + "fmaf32" => { + let [a, b, c] = check_intrinsic_arg_count(args)?; + let a = this.read_scalar(a)?.to_f32()?; + let b = this.read_scalar(b)?.to_f32()?; + let c = this.read_scalar(c)?.to_f32()?; + let res = a.mul_add(b, c).value; + let res = this.adjust_nan(res, &[a, b, c]); + this.write_scalar(res, dest)?; + } + "fmaf64" => { + let [a, b, c] = check_intrinsic_arg_count(args)?; + let a = this.read_scalar(a)?.to_f64()?; + let b = this.read_scalar(b)?.to_f64()?; + let c = this.read_scalar(c)?.to_f64()?; + let res = a.mul_add(b, c).value; + let res = this.adjust_nan(res, &[a, b, c]); + this.write_scalar(res, dest)?; + } + + "fmuladdf32" => { + let [a, b, c] = check_intrinsic_arg_count(args)?; + let a = this.read_scalar(a)?.to_f32()?; + let b = this.read_scalar(b)?.to_f32()?; + let c = this.read_scalar(c)?.to_f32()?; + let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random(); + let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value }; + let res = this.adjust_nan(res, &[a, b, c]); + this.write_scalar(res, dest)?; + } + "fmuladdf64" => { + let [a, b, c] = check_intrinsic_arg_count(args)?; + let a = this.read_scalar(a)?.to_f64()?; + let b = this.read_scalar(b)?.to_f64()?; + let c = this.read_scalar(c)?.to_f64()?; + let fuse: bool = this.machine.float_nondet && this.machine.rng.get_mut().random(); + let res = if fuse { a.mul_add(b, c).value } else { ((a * b).value + c).value }; + let res = this.adjust_nan(res, &[a, b, c]); + this.write_scalar(res, dest)?; + } + + #[rustfmt::skip] + | "fadd_fast" + | "fsub_fast" + | "fmul_fast" + | "fdiv_fast" + | "frem_fast" + => { + let [a, b] = check_intrinsic_arg_count(args)?; + let a = this.read_immediate(a)?; + let b = this.read_immediate(b)?; + let op = match intrinsic_name { + "fadd_fast" => mir::BinOp::Add, + "fsub_fast" => mir::BinOp::Sub, + "fmul_fast" => mir::BinOp::Mul, + "fdiv_fast" => mir::BinOp::Div, + "frem_fast" => mir::BinOp::Rem, + _ => bug!(), + }; + let float_finite = |x: &ImmTy<'tcx>| -> InterpResult<'tcx, bool> { + let ty::Float(fty) = x.layout.ty.kind() else { + bug!("float_finite: non-float input type {}", x.layout.ty) + }; + interp_ok(match fty { + FloatTy::F16 => x.to_scalar().to_f16()?.is_finite(), + FloatTy::F32 => x.to_scalar().to_f32()?.is_finite(), + FloatTy::F64 => x.to_scalar().to_f64()?.is_finite(), + FloatTy::F128 => x.to_scalar().to_f128()?.is_finite(), + }) + }; + match (float_finite(&a)?, float_finite(&b)?) { + (false, false) => throw_ub_format!( + "`{intrinsic_name}` intrinsic called with non-finite value as both parameters", + ), + (false, _) => throw_ub_format!( + "`{intrinsic_name}` intrinsic called with non-finite value as first parameter", + ), + (_, false) => throw_ub_format!( + "`{intrinsic_name}` intrinsic called with non-finite value as second parameter", + ), + _ => {} + } + let res = this.binary_op(op, &a, &b)?; + // This cannot be a NaN so we also don't have to apply any non-determinism. + // (Also, `binary_op` already called `generate_nan` if needed.) + if !float_finite(&res)? { + throw_ub_format!("`{intrinsic_name}` intrinsic produced non-finite value as result"); + } + // Apply a relative error of 4ULP to simulate non-deterministic precision loss + // due to optimizations. + let res = math::apply_random_float_error_to_imm(this, res, 4)?; + this.write_immediate(*res, dest)?; + } + + "float_to_int_unchecked" => { + let [val] = check_intrinsic_arg_count(args)?; + let val = this.read_immediate(val)?; + + let res = this + .float_to_int_checked(&val, dest.layout, Round::TowardZero)? + .ok_or_else(|| { + err_ub_format!( + "`float_to_int_unchecked` intrinsic called on {val} which cannot be represented in target type `{:?}`", + dest.layout.ty + ) + })?; + + this.write_immediate(*res, dest)?; + } + + // Operations that need host floats. + #[rustfmt::skip] + | "sinf32" + | "cosf32" + | "expf32" + | "exp2f32" + | "logf32" + | "log10f32" + | "log2f32" + => { + let [f] = check_intrinsic_arg_count(args)?; + let f = this.read_scalar(f)?.to_f32()?; + + let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| { + // Using host floats (but it's fine, these operations do not have + // guaranteed precision). + let host = f.to_host(); + let res = match intrinsic_name { + "sinf32" => host.sin(), + "cosf32" => host.cos(), + "expf32" => host.exp(), + "exp2f32" => host.exp2(), + "logf32" => host.ln(), + "log10f32" => host.log10(), + "log2f32" => host.log2(), + _ => bug!(), + }; + let res = res.to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + let res = math::apply_random_float_error_ulp( + this, + res, + 4, + ); + + // Clamp the result to the guaranteed range of this function according to the C standard, + // if any. + math::clamp_float_value(intrinsic_name, res) + }); + let res = this.adjust_nan(res, &[f]); + this.write_scalar(res, dest)?; + } + + #[rustfmt::skip] + | "sinf64" + | "cosf64" + | "expf64" + | "exp2f64" + | "logf64" + | "log10f64" + | "log2f64" + => { + let [f] = check_intrinsic_arg_count(args)?; + let f = this.read_scalar(f)?.to_f64()?; + + let res = math::fixed_float_value(this, intrinsic_name, &[f]).unwrap_or_else(|| { + // Using host floats (but it's fine, these operations do not have + // guaranteed precision). + let host = f.to_host(); + let res = match intrinsic_name { + "sinf64" => host.sin(), + "cosf64" => host.cos(), + "expf64" => host.exp(), + "exp2f64" => host.exp2(), + "logf64" => host.ln(), + "log10f64" => host.log10(), + "log2f64" => host.log2(), + _ => bug!(), + }; + let res = res.to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + let res = math::apply_random_float_error_ulp( + this, + res, + 4, + ); + + // Clamp the result to the guaranteed range of this function according to the C standard, + // if any. + math::clamp_float_value(intrinsic_name, res) + }); + let res = this.adjust_nan(res, &[f]); + this.write_scalar(res, dest)?; + } + + "powf32" => { + let [f1, f2] = check_intrinsic_arg_count(args)?; + let f1 = this.read_scalar(f1)?.to_f32()?; + let f2 = this.read_scalar(f2)?.to_f32()?; + + let res = + math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| { + // Using host floats (but it's fine, this operation does not have guaranteed precision). + let res = f1.to_host().powf(f2.to_host()).to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + math::apply_random_float_error_ulp(this, res, 4) + }); + let res = this.adjust_nan(res, &[f1, f2]); + this.write_scalar(res, dest)?; + } + "powf64" => { + let [f1, f2] = check_intrinsic_arg_count(args)?; + let f1 = this.read_scalar(f1)?.to_f64()?; + let f2 = this.read_scalar(f2)?.to_f64()?; + + let res = + math::fixed_float_value(this, intrinsic_name, &[f1, f2]).unwrap_or_else(|| { + // Using host floats (but it's fine, this operation does not have guaranteed precision). + let res = f1.to_host().powf(f2.to_host()).to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + math::apply_random_float_error_ulp(this, res, 4) + }); + let res = this.adjust_nan(res, &[f1, f2]); + this.write_scalar(res, dest)?; + } + + "powif32" => { + let [f, i] = check_intrinsic_arg_count(args)?; + let f = this.read_scalar(f)?.to_f32()?; + let i = this.read_scalar(i)?.to_i32()?; + + let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| { + // Using host floats (but it's fine, this operation does not have guaranteed precision). + let res = f.to_host().powi(i).to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + math::apply_random_float_error_ulp(this, res, 4) + }); + let res = this.adjust_nan(res, &[f]); + this.write_scalar(res, dest)?; + } + "powif64" => { + let [f, i] = check_intrinsic_arg_count(args)?; + let f = this.read_scalar(f)?.to_f64()?; + let i = this.read_scalar(i)?.to_i32()?; + + let res = math::fixed_powi_value(this, f, i).unwrap_or_else(|| { + // Using host floats (but it's fine, this operation does not have guaranteed precision). + let res = f.to_host().powi(i).to_soft(); + + // Apply a relative error of 4ULP to introduce some non-determinism + // simulating imprecise implementations and optimizations. + math::apply_random_float_error_ulp(this, res, 4) + }); + let res = this.adjust_nan(res, &[f]); + this.write_scalar(res, dest)?; + } + + _ => return interp_ok(EmulateItemResult::NotSupported), + } + + interp_ok(EmulateItemResult::NeedsReturn) + } +} |