GNU properties are emitted to provide some information about the features
used in the generated code like PAC, BTI, or GCS. However, no debug
comment are emitted in the generated assembly even if -dA is provided.
This makes understanding the information stored in the .note.gnu.property
section more difficult than needed.
This patch adds assembly comments (if -dA is provided) next to the GNU
properties. For instance, if PAC and BTI are enabled, it will emit:
.word 3 // GNU_PROPERTY_AARCH64_FEATURE_1_AND (BTI, PAC)
gcc/ChangeLog:
* config/aarch64/aarch64.cc
(aarch64_file_end_indicate_exec_stack): Emit assembly comments.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/bti-1.c: Emit assembly comments, and update
test assertion.
---
gcc/config/aarch64/aarch64.cc | 41 +++++++++++++++++++++++-
gcc/testsuite/gcc.target/aarch64/bti-1.c | 5 +--
2 files changed, 43 insertions(+), 3 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 4b2e7a690c6..6d9075011ec 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -98,6 +98,8 @@
#include "ipa-fnsummary.h"
#include "hash-map.h"
+#include <numeric>
+
/* This file should be included last. */
#include "target-def.h"
@@ -29129,8 +29131,45 @@ aarch64_file_end_indicate_exec_stack ()
data = feature_1_and. */
assemble_integer (GEN_INT (GNU_PROPERTY_AARCH64_FEATURE_1_AND), 4, 32,
1);
assemble_integer (GEN_INT (4), 4, 32, 1);
- assemble_integer (GEN_INT (feature_1_and), 4, 32, 1);
+ if (!flag_debug_asm)
+ assemble_integer (GEN_INT (feature_1_and), 4, 32, 1);
+ else
+ {
+ asm_fprintf (asm_out_file, "\t.word\t%u", feature_1_and);
+
+ auto join_s = [] (std::string s1,
+ const std::string &s2,
+ const std::string &separator = ", ") -> std::string
+ {
+ return std::move (s1)
+ .append (separator)
+ .append (s2);
+ };
+
+ auto features_to_string
+ = [&join_s] (unsigned feature_1_and) -> std::string
+ {
+ std::vector<std::string> feature_bits;
+ if (feature_1_and & GNU_PROPERTY_AARCH64_FEATURE_1_BTI)
+ feature_bits.push_back ("BTI");
+ if (feature_1_and & GNU_PROPERTY_AARCH64_FEATURE_1_PAC)
+ feature_bits.push_back ("PAC");
+ if (feature_1_and & GNU_PROPERTY_AARCH64_FEATURE_1_GCS)
+ feature_bits.push_back ("GCS");
+
+ if (feature_bits.empty ())
+ return {};
+ return std::accumulate(std::next(feature_bits.cbegin()),
+ feature_bits.cend(),
+ feature_bits[0],
+ join_s);
+ };
+ auto const& s_features = features_to_string (feature_1_and);
+ asm_fprintf (asm_out_file,
+ "\t%s GNU_PROPERTY_AARCH64_FEATURE_1_AND (%s)\n",
+ ASM_COMMENT_START, s_features.c_str ());
+ }
/* Pad the size of the note to the required alignment. */
assemble_align (POINTER_SIZE);
}
diff --git a/gcc/testsuite/gcc.target/aarch64/bti-1.c
b/gcc/testsuite/gcc.target/aarch64/bti-1.c
index 5a556b08ed1..e48017abc35 100644
--- a/gcc/testsuite/gcc.target/aarch64/bti-1.c
+++ b/gcc/testsuite/gcc.target/aarch64/bti-1.c
@@ -1,6 +1,6 @@
/* { dg-do compile } */
/* -Os to create jump table. */
-/* { dg-options "-Os" } */
+/* { dg-options "-Os -dA" } */
/* { dg-require-effective-target lp64 } */
/* If configured with --enable-standard-branch-protection, don't use
command line option. */
@@ -61,4 +61,5 @@ lab2:
}
/* { dg-final { scan-assembler-times "hint\t34" 1 } } */
/* { dg-final { scan-assembler-times "hint\t36" 12 } } */
-/* { dg-final { scan-assembler ".note.gnu.property" { target *-*-linux* } } }
*/
+/* { dg-final { scan-assembler "\.section\t\.note\.gnu\.property" { target
*-*-linux* } } } */
+/* { dg-final { scan-assembler "\.word\t7\t\/\/
GNU_PROPERTY_AARCH64_FEATURE_1_AND \\(BTI, PAC, GCS\\)" { target *-*-linux* } }
} */
\ No newline at end of file
--
2.46.1
