1 files changed, 74 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/intrinsics/cpuid.rs b/compiler/rustc_codegen_cranelift/src/intrinsics/cpuid.rs
new file mode 100644
index 000000000..d02dfd93c
--- /dev/null
+++ b/compiler/rustc_codegen_cranelift/src/intrinsics/cpuid.rs
@@ -0,0 +1,74 @@
+//! Emulation of a subset of the cpuid x86 instruction.
+
+use crate::prelude::*;
+
+/// Emulates a subset of the cpuid x86 instruction.
+///
+/// This emulates an intel cpu with sse and sse2 support, but which doesn't support anything else.
+pub(crate) fn codegen_cpuid_call<'tcx>(
+    fx: &mut FunctionCx<'_, '_, 'tcx>,
+    leaf: Value,
+    _sub_leaf: Value,
+) -> (Value, Value, Value, Value) {
+    let leaf_0 = fx.bcx.create_block();
+    let leaf_1 = fx.bcx.create_block();
+    let leaf_7 = fx.bcx.create_block();
+    let leaf_8000_0000 = fx.bcx.create_block();
+    let leaf_8000_0001 = fx.bcx.create_block();
+    let unsupported_leaf = fx.bcx.create_block();
+
+    let dest = fx.bcx.create_block();
+    let eax = fx.bcx.append_block_param(dest, types::I32);
+    let ebx = fx.bcx.append_block_param(dest, types::I32);
+    let ecx = fx.bcx.append_block_param(dest, types::I32);
+    let edx = fx.bcx.append_block_param(dest, types::I32);
+
+    let mut switch = cranelift_frontend::Switch::new();
+    switch.set_entry(0, leaf_0);
+    switch.set_entry(1, leaf_1);
+    switch.set_entry(7, leaf_7);
+    switch.set_entry(0x8000_0000, leaf_8000_0000);
+    switch.set_entry(0x8000_0001, leaf_8000_0001);
+    switch.emit(&mut fx.bcx, leaf, unsupported_leaf);
+
+    fx.bcx.switch_to_block(leaf_0);
+    let max_basic_leaf = fx.bcx.ins().iconst(types::I32, 1);
+    let vend0 = fx.bcx.ins().iconst(types::I32, i64::from(u32::from_le_bytes(*b"Genu")));
+    let vend2 = fx.bcx.ins().iconst(types::I32, i64::from(u32::from_le_bytes(*b"ineI")));
+    let vend1 = fx.bcx.ins().iconst(types::I32, i64::from(u32::from_le_bytes(*b"ntel")));
+    fx.bcx.ins().jump(dest, &[max_basic_leaf, vend0, vend1, vend2]);
+
+    fx.bcx.switch_to_block(leaf_1);
+    let cpu_signature = fx.bcx.ins().iconst(types::I32, 0);
+    let additional_information = fx.bcx.ins().iconst(types::I32, 0);
+    let ecx_features = fx.bcx.ins().iconst(types::I32, 0);
+    let edx_features = fx.bcx.ins().iconst(types::I32, 1 << 25 /* sse */ | 1 << 26 /* sse2 */);
+    fx.bcx.ins().jump(dest, &[cpu_signature, additional_information, ecx_features, edx_features]);
+
+    fx.bcx.switch_to_block(leaf_7);
+    // This leaf technically has subleaves, but we just return zero for all subleaves.
+    let zero = fx.bcx.ins().iconst(types::I32, 0);
+    fx.bcx.ins().jump(dest, &[zero, zero, zero, zero]);
+
+    fx.bcx.switch_to_block(leaf_8000_0000);
+    let extended_max_basic_leaf = fx.bcx.ins().iconst(types::I32, 0);
+    let zero = fx.bcx.ins().iconst(types::I32, 0);
+    fx.bcx.ins().jump(dest, &[extended_max_basic_leaf, zero, zero, zero]);
+
+    fx.bcx.switch_to_block(leaf_8000_0001);
+    let zero = fx.bcx.ins().iconst(types::I32, 0);
+    let proc_info_ecx = fx.bcx.ins().iconst(types::I32, 0);
+    let proc_info_edx = fx.bcx.ins().iconst(types::I32, 0);
+    fx.bcx.ins().jump(dest, &[zero, zero, proc_info_ecx, proc_info_edx]);
+
+    fx.bcx.switch_to_block(unsupported_leaf);
+    crate::trap::trap_unreachable(
+        fx,
+        "__cpuid_count arch intrinsic doesn't yet support specified leaf",
+    );
+
+    fx.bcx.switch_to_block(dest);
+    fx.bcx.ins().nop();
+
+    (eax, ebx, ecx, edx)
+}