Rollup merge of #124741 - nebulark:patchable-function-entries-pr, r=estebank,workingjubilee

patchable-function-entry: Add unstable compiler flag and attribute

Tracking issue: #123115

Add the -Z patchable-function-entry compiler flag and the #[patchable_function_entry(prefix_nops = m, entry_nops = n)] attribute.
Rebased and adjusted the canditate implementation to match changes in the RFC.

4 files changed, 53 insertions, 0 deletions

diff --git a/tests/ui/patchable-function-entry/patchable-function-entry-attribute.rs b/tests/ui/patchable-function-entry/patchable-function-entry-attribute.rs
new file mode 100644
index 00000000000..1e376c9ff3c
--- /dev/null
+++ b/tests/ui/patchable-function-entry/patchable-function-entry-attribute.rs
@@ -0,0 +1,17 @@
+#![feature(patchable_function_entry)]
+fn main() {}
+
+#[patchable_function_entry(prefix_nops = 256, entry_nops = 0)]//~error: integer value out of range
+pub fn too_high_pnops() {}
+
+#[patchable_function_entry(prefix_nops = "stringvalue", entry_nops = 0)]//~error: invalid literal value
+pub fn non_int_nop() {}
+
+#[patchable_function_entry]//~error: malformed `patchable_function_entry` attribute input
+pub fn malformed_attribute() {}
+
+#[patchable_function_entry(prefix_nops = 10, something = 0)]//~error: unexpected parameter name
+pub fn unexpected_parameter_name() {}
+
+#[patchable_function_entry()]//~error: must specify at least one parameter
+pub fn no_parameters_given() {}
diff --git a/tests/ui/patchable-function-entry/patchable-function-entry-attribute.stderr b/tests/ui/patchable-function-entry/patchable-function-entry-attribute.stderr
new file mode 100644
index 00000000000..d9710c6e6a2
--- /dev/null
+++ b/tests/ui/patchable-function-entry/patchable-function-entry-attribute.stderr
@@ -0,0 +1,32 @@
+error: malformed `patchable_function_entry` attribute input
+  --> $DIR/patchable-function-entry-attribute.rs:10:1
+   |
+LL | #[patchable_function_entry]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[patchable_function_entry(prefix_nops = m, entry_nops = n)]`
+
+error: integer value out of range
+  --> $DIR/patchable-function-entry-attribute.rs:4:42
+   |
+LL | #[patchable_function_entry(prefix_nops = 256, entry_nops = 0)]
+   |                                          ^^^ value must be between `0` and `255`
+
+error: invalid literal value
+  --> $DIR/patchable-function-entry-attribute.rs:7:42
+   |
+LL | #[patchable_function_entry(prefix_nops = "stringvalue", entry_nops = 0)]
+   |                                          ^^^^^^^^^^^^^ value must be an integer between `0` and `255`
+
+error: unexpected parameter name
+  --> $DIR/patchable-function-entry-attribute.rs:13:46
+   |
+LL | #[patchable_function_entry(prefix_nops = 10, something = 0)]
+   |                                              ^^^^^^^^^^^^^ expected prefix_nops or entry_nops
+
+error: must specify at least one parameter
+  --> $DIR/patchable-function-entry-attribute.rs:16:1
+   |
+LL | #[patchable_function_entry()]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+
diff --git a/tests/ui/patchable-function-entry/patchable-function-entry-flags.rs b/tests/ui/patchable-function-entry/patchable-function-entry-flags.rs
new file mode 100644
index 00000000000..cb5bc62b6b3
--- /dev/null
+++ b/tests/ui/patchable-function-entry/patchable-function-entry-flags.rs
@@ -0,0 +1,2 @@
+//@ compile-flags: -Z patchable-function-entry=1,2
+fn main() {}
diff --git a/tests/ui/patchable-function-entry/patchable-function-entry-flags.stderr b/tests/ui/patchable-function-entry/patchable-function-entry-flags.stderr
new file mode 100644
index 00000000000..b09af94a615
--- /dev/null
+++ b/tests/ui/patchable-function-entry/patchable-function-entry-flags.stderr
@@ -0,0 +1,2 @@
+error: incorrect value `1,2` for unstable option `patchable-function-entry` - either two comma separated integers (total_nops,prefix_nops), with prefix_nops <= total_nops, or one integer (total_nops) was expected
+