From d3fe767c16e7c528e4fc71c8a68ac14b4573d880 Mon Sep 17 00:00:00 2001
From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 9 Nov 2022 21:49:52 +0000
Subject: [PATCH] c-family: Support #pragma region/endregion [PR85487]
These pragmas are used by some editors to mark regions of code for
grouping and folding. GCC should silently ignore them, rather than
giving -Wunknown-pragmas warnings.
PR c/85487
gcc/ChangeLog:
* doc/cpp/pragmas.rst (Pragmas): Document region pragmas.
gcc/c-family/ChangeLog:
* c-pragma.cc (handle_pragma_ignore): New function.
(init_pragma): Register region and endregion pragmas.
gcc/testsuite/ChangeLog:
* c-c++-common/pragma-region.c: New test.
---
gcc/c-family/c-pragma.cc | 9 +++++++++
gcc/doc/cpp/pragmas.rst | 3 +++
gcc/testsuite/c-c++-common/pragma-region.c | 11 +++++++++++
3 files changed, 23 insertions(+)
create mode 100644 gcc/testsuite/c-c++-common/pragma-region.c
diff --git a/gcc/c-family/c-pragma.cc b/gcc/c-family/c-pragma.cc
index b5a4b3c970f2..142a46441ac2 100644
--- a/gcc/c-family/c-pragma.cc
+++ b/gcc/c-family/c-pragma.cc
@@ -1403,6 +1403,12 @@ handle_pragma_message (cpp_reader *)
TREE_STRING_POINTER (message));
}
+/* Ignore a no-op pragma that GCC recognizes, but which has no effect. */
+static void
+handle_pragma_ignore (cpp_reader *)
+{
+}
+
/* Mark whether the current location is valid for a STDC pragma. */
static bool valid_location_for_stdc_pragma;
@@ -1870,6 +1876,9 @@ init_pragma (void)
c_register_pragma ("GCC", "pop_options", handle_pragma_pop_options);
c_register_pragma ("GCC", "reset_options", handle_pragma_reset_options);
+ c_register_pragma (0, "region", handle_pragma_ignore);
+ c_register_pragma (0, "endregion", handle_pragma_ignore);
+
c_register_pragma ("STDC", "FLOAT_CONST_DECIMAL64",
handle_pragma_float_const_decimal64);
diff --git a/gcc/doc/cpp/pragmas.rst b/gcc/doc/cpp/pragmas.rst
index da07cebf4a1a..78277d7b6232 100644
--- a/gcc/doc/cpp/pragmas.rst
+++ b/gcc/doc/cpp/pragmas.rst
@@ -119,3 +119,6 @@ GCC plugins may provide their own pragmas.
file will never be read again, no matter what. It is a less-portable
alternative to using :samp:`#ifndef` to guard the contents of header files
against multiple inclusions.
+
+``#pragma region {tokens}...``, ``#pragma endregion {tokens}...``
+ These pragmas are accepted, but have no effect.
diff --git a/gcc/testsuite/c-c++-common/pragma-region.c b/gcc/testsuite/c-c++-common/pragma-region.c
new file mode 100644
index 000000000000..8e0cbe1f16fe
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pragma-region.c
@@ -0,0 +1,11 @@
+/* { dg-options "-Wunknown-pragmas" } */
+/* { dg-final { scan-assembler "code_within_region" } } */
+/* { dg-final { scan-assembler "code_within_named_region" } } */
+
+#pragma region
+void code_within_region() { }
+#pragma endregion
+
+#pragma region ignored name
+void code_within_named_region() { }
+#pragma endregion // ignored comment
--
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