1 files changed, 94 insertions, 0 deletions
diff --git a/vendor/compiler_builtins/src/x86_64.rs b/vendor/compiler_builtins/src/x86_64.rs
new file mode 100644
index 000000000..393eeddd8
--- /dev/null
+++ b/vendor/compiler_builtins/src/x86_64.rs
@@ -0,0 +1,94 @@
+#![allow(unused_imports)]
+
+use core::intrinsics;
+
+// NOTE These functions are implemented using assembly because they using a custom
+// calling convention which can't be implemented using a normal Rust function
+
+// NOTE These functions are never mangled as they are not tested against compiler-rt
+// and mangling ___chkstk would break the `jmp ___chkstk` instruction in __alloca
+
+intrinsics! {
+    #[naked]
+    #[cfg(all(
+        windows,
+        target_env = "gnu",
+        not(feature = "no-asm")
+    ))]
+    pub unsafe extern "C" fn ___chkstk_ms() {
+        core::arch::asm!(
+            "push   %rcx",
+            "push   %rax",
+            "cmp    $0x1000,%rax",
+            "lea    24(%rsp),%rcx",
+            "jb     1f",
+            "2:",
+            "sub    $0x1000,%rcx",
+            "test   %rcx,(%rcx)",
+            "sub    $0x1000,%rax",
+            "cmp    $0x1000,%rax",
+            "ja     2b",
+            "1:",
+            "sub    %rax,%rcx",
+            "test   %rcx,(%rcx)",
+            "pop    %rax",
+            "pop    %rcx",
+            "ret",
+            options(noreturn, att_syntax)
+        );
+    }
+
+    #[naked]
+    #[cfg(all(
+        windows,
+        target_env = "gnu",
+        not(feature = "no-asm")
+    ))]
+    pub unsafe extern "C" fn __alloca() {
+        core::arch::asm!(
+            "mov    %rcx,%rax", // x64 _alloca is a normal function with parameter in rcx
+            "jmp    ___chkstk", // Jump to ___chkstk since fallthrough may be unreliable"
+            options(noreturn, att_syntax)
+        );
+    }
+
+    #[naked]
+    #[cfg(all(
+        windows,
+        target_env = "gnu",
+        not(feature = "no-asm")
+    ))]
+    pub unsafe extern "C" fn ___chkstk() {
+        core::arch::asm!(
+            "push   %rcx",
+            "cmp    $0x1000,%rax",
+            "lea    16(%rsp),%rcx", // rsp before calling this routine -> rcx
+            "jb     1f",
+            "2:",
+            "sub    $0x1000,%rcx",
+            "test   %rcx,(%rcx)",
+            "sub    $0x1000,%rax",
+            "cmp    $0x1000,%rax",
+            "ja     2b",
+            "1:",
+            "sub    %rax,%rcx",
+            "test   %rcx,(%rcx)",
+            "lea    8(%rsp),%rax",  // load pointer to the return address into rax
+            "mov    %rcx,%rsp",     // install the new top of stack pointer into rsp
+            "mov    -8(%rax),%rcx", // restore rcx
+            "push   (%rax)",        // push return address onto the stack
+            "sub    %rsp,%rax",     // restore the original value in rax
+            "ret",
+            options(noreturn, att_syntax)
+        );
+    }
+}
+
+// HACK(https://github.com/rust-lang/rust/issues/62785): x86_64-unknown-uefi needs special LLVM
+// support unless we emit the _fltused
+mod _fltused {
+    #[no_mangle]
+    #[used]
+    #[cfg(target_os = "uefi")]
+    static _fltused: i32 = 0;
+}