Enable non-leaf Frame Pointers for Arm64EC Windows

compiler/rustc_target/src/spec/targets/arm64ec_pc_windows_msvc.rs

@@ -1,4 +1,4 @@
-use crate::spec::{LinkerFlavor, Lld, Target, TargetMetadata, add_link_args, base};
+use crate::spec::{FramePointer, LinkerFlavor, Lld, Target, TargetMetadata, add_link_args, base};
 
 pub(crate) fn target() -> Target {
     let mut base = base::windows_msvc::opts();
@@ -10,6 +10,12 @@ pub(crate) fn target() -> Target {
         &["/machine:arm64ec", "softintrin.lib"],
     );
 
+    // Microsoft recommends enabling frame pointers on Arm64 Windows.
+    // From https://learn.microsoft.com/en-us/cpp/build/arm64-windows-abi-conventions?view=msvc-170#integer-registers
+    // "The frame pointer (x29) is required for compatibility with fast stack walking used by ETW
+    // and other services. It must point to the previous {x29, x30} pair on the stack."
+    base.frame_pointer = FramePointer::NonLeaf;
+
     Target {
         llvm_target: "arm64ec-pc-windows-msvc".into(),
         metadata: TargetMetadata {

tests/assembly/asm/aarch64-types.rs

@@ -86,10 +86,12 @@ pub unsafe fn sym_static() {
 
 // Regression test for #75761
 // CHECK-LABEL: {{("#)?}}issue_75761{{"?}}
-// CHECK: str {{.*}}x30
+// aarch64: str {{.*}}x30
+// arm64ec: stp {{.*}}x30
 // CHECK: //APP
 // CHECK: //NO_APP
-// CHECK: ldr {{.*}}x30
+// aarch64: ldr {{.*}}x30
+// arm64ec: ldp {{.*}}x30
 #[no_mangle]
 pub unsafe fn issue_75761() {
     asm!("", out("v0") _, out("x30") _);