From bb0fda5ea25e0011df26e2f1950d5a3d871b30c0 Mon Sep 17 00:00:00 2001
From: Nelson Elhage <nelhage@nelhage.com>
Date: Wed, 27 May 2020 12:43:50 -0700
Subject: [PATCH 1/3] Add some optimization options to our asm

Since we don't actually emit code to speak of, we can let rustc/LLVM
know that we don't clobber anything, letting them avoid
saving/restoring registers or other state around the probe.

We can't mark the probe as `pure`, even though our _code_ is `pure`,
since that would enable LLVM to delete it entirely (since we have no
outputs).
---
 src/platform/systemtap.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/platform/systemtap.rs b/src/platform/systemtap.rs
index 7f04cb0..ad96545 100644
--- a/src/platform/systemtap.rs
+++ b/src/platform/systemtap.rs
@@ -181,7 +181,7 @@ macro_rules! sdt_asm(
 #[doc(hidden)]
 #[macro_export]
 macro_rules! _sdt_asm(
-    ($addr:tt, options $opt:tt, $provider:ident, $name:ident, $argstr:tt, $($arg:expr),*) => (
+    ($addr:tt, options ($opt:tt), $provider:ident, $name:ident, $argstr:tt, $($arg:expr),*) => (
         asm!(concat!(r#"
 990:    nop
         .pushsection .note.stapsdt,"?","note"
@@ -208,6 +208,6 @@ _.stapsdt.base: .space 1
 "#
             ),
             $(in(reg) (($arg) as isize) ,)*
-            options $opt,
+            options($opt, nomem, nostack, preserves_flags),
         )
     ));

From 2ed4e987e7d30a8845d9e6d6ebed1cb8bbfbb97b Mon Sep 17 00:00:00 2001
From: Nelson Elhage <nelhage@nelhage.com>
Date: Thu, 28 May 2020 18:51:03 -0700
Subject: [PATCH 2/3] nonmem -> readonly, per code review

Make it hopefully easier for debuggers stopped at a probe to get a
consistent view of the world.
---
 src/platform/systemtap.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/platform/systemtap.rs b/src/platform/systemtap.rs
index ad96545..a23f133 100644
--- a/src/platform/systemtap.rs
+++ b/src/platform/systemtap.rs
@@ -208,6 +208,6 @@ _.stapsdt.base: .space 1
 "#
             ),
             $(in(reg) (($arg) as isize) ,)*
-            options($opt, nomem, nostack, preserves_flags),
+            options($opt, readonly, nostack, preserves_flags),
         )
     ));

From 37d6ab58edc2b02569199c9b9720b365a0a6f31e Mon Sep 17 00:00:00 2001
From: Nelson Elhage <nelhage@nelhage.com>
Date: Fri, 29 May 2020 10:18:33 -0700
Subject: [PATCH 3/3] Fix asm options for non-x86 platforms

---
 src/platform/systemtap.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/platform/systemtap.rs b/src/platform/systemtap.rs
index a23f133..34fe3ba 100644
--- a/src/platform/systemtap.rs
+++ b/src/platform/systemtap.rs
@@ -181,7 +181,7 @@ macro_rules! sdt_asm(
 #[doc(hidden)]
 #[macro_export]
 macro_rules! _sdt_asm(
-    ($addr:tt, options ($opt:tt), $provider:ident, $name:ident, $argstr:tt, $($arg:expr),*) => (
+    ($addr:tt, options ($($opt:ident),*), $provider:ident, $name:ident, $argstr:tt, $($arg:expr),*) => (
         asm!(concat!(r#"
 990:    nop
         .pushsection .note.stapsdt,"?","note"
@@ -208,6 +208,6 @@ _.stapsdt.base: .space 1
 "#
             ),
             $(in(reg) (($arg) as isize) ,)*
-            options($opt, readonly, nostack, preserves_flags),
+            options(readonly, nostack, preserves_flags, $($opt),*),
         )
     ));