added new test. Adjusted test as we dropped the 'no jump to first instruction' condition

Author: nebulark

tests/run-make/hotpatch-unaffected/rmake.rs

@@ -1,9 +1,11 @@
 // Check if hotpatch leaves the functions that are already hotpatchable untouched
 
-//@ revisions: x32 x64
+//@ revisions: x32 x64 aarch64
 //@[x32] only-x86
 //@[x64] only-x86_64
-// Reason: hotpatch is only implemented for X86
+//@[aarch64] only-aarch64
+
+// Reason: hotpatch is only implemented for X86 and aarch64
 
 use run_make_support::{assertion_helpers, llvm, rustc};
 

tests/run-make/hotpatch/lib.rs

@@ -1,38 +1,18 @@
 // hotpatch has two requirements:
-// 1. the first instruction of a functin must be at least two bytes long
-// 2. there must not be a jump to the first instruction
+// 1) the first instruction of a functin must be at least two bytes long
+// 2) there must not be a jump to the first instruction
 
-// the hotpatch flag should insert nops as needed to fullfil the requirements,
-// but only if the the function does not already fulfill them.
-// Over 99% of function in regular codebases already fulfill the conditions,
-//  so its important to check that those are
-// unneccessarily affected
-
-// ----------------------------------------------------------------------------------------------
-
-// regularly this tailcall would jump to the first instruction the function
-// CHECK-LABEL: <tailcall_fn>:
-// CHECK: jne 0x0 <tailcall_fn>
-
-// hotpatch insert nops so that the tailcall will not jump to the first instruction of the function
-// HOTPATCH-LABEL: <tailcall_fn>:
-// HOTPATCH-NOT: jne 0x0 <tailcall_fn>
-
-#[no_mangle]
-pub fn tailcall_fn() {
-    use std::sync::atomic::{AtomicUsize, Ordering};
-    static COUNT: AtomicUsize = AtomicUsize::new(0);
-    if COUNT.fetch_sub(1, Ordering::Relaxed) != 0 {
-        tailcall_fn()
-    }
-}
+// The LLVM attribute we use '"patchable-function", "prologue-short-redirect"' only ensures 1)
+// However in practice 2) rarely matters. Its rare that it occurs and the problems it caused can be
+// avoided by the hotpatch tool.
+// In this test we check if 1) is ensured by inserted nops as needed
 
 // ----------------------------------------------------------------------------------------------
 
 // empty_fn just returns. Note that 'ret' is a single byte instruction, but hotpatch requires
 // a two or more byte instructions to be at the start of the functions.
 // Preferably we would also tests a different single byte instruction,
-// but I was not able to make rustc emit anything but 'ret'.
+// but I was not able to find an example with another one byte intstruction.
 
 // check that if the first instruction is just a single byte, so our test is valid
 // CHECK-LABEL: <empty_fn>:

tests/run-make/hotpatch/rmake.rs

@@ -1,11 +1,12 @@
-// Check if hotpatch only makes the functions hotpachable that were not,
-// but leaving the other functions untouched
+// Check if hotpatch makes the functions hotpachable that were not
 // More details in lib.rs
 
 //@ revisions: x32 x64
 //@[x32] only-x86
 //@[x64] only-x86_64
-// Reason: hotpatch is only implemented for X86
+
+// Reason: hotpatch is only implemented for x86 and aarch64, but for aarch64 they
+// are always hotpatchable so we don't need to check it
 
 use run_make_support::{llvm, rustc};
 
@@ -18,7 +19,7 @@ fn main() {
 
     fn dump_lib(libname: &str) -> String {
         llvm::llvm_objdump()
-            .arg("--disassemble-symbols=tailcall_fn,empty_fn")
+            .arg("--disassemble-symbols=empty_fn")
             .input(libname)
             .run()
             .stdout_utf8()

tests/run-make/hotpatch_pdb/main.rs

@@ -0,0 +1,6 @@
+// CHECK: S_OBJNAME{{.*}}hotpatch_pdb{{.*}}.o
+// CHECK: S_COMPILE3
+// CHECK-NOT: S_
+// CHECK: flags = {{.*}}hot patchable
+
+pub fn main() {}

tests/run-make/hotpatch_pdb/rmake.rs

@@ -0,0 +1,30 @@
+// Check if hotpatch flag is present in the Codeview.
+// This is need so linkers actually pad functions when given the functionpadmin arg.
+
+//@ revisions: x32 x64 aarch64
+//@[x32] only-x86
+//@[x64] only-x86_64
+//@[aarch64] only-aarch64
+
+// Reason: Hotpatch is only implemented for x86 and aarch64
+
+use run_make_support::{llvm, rustc};
+
+fn main() {
+    let output = rustc()
+        .input("main.rs")
+        .arg("-g")
+        .arg("-Zhotpatch")
+        .crate_name("hotpatch_pdb")
+        .crate_type("bin")
+        .run();
+
+    let pdbutil_output = llvm::llvm_pdbutil()
+        .arg("dump")
+        .arg("-symbols")
+        .input("hotpatch_pdb.pdb")
+        .run()
+        .stdout_utf8();
+
+    llvm::llvm_filecheck().patterns("main.rs").stdin_buf(&pdbutil_output).run();
+}