aarch64: fix off-by-one in reading cpuinfo

Fixes: 341573406b39
Don't subtract one from the result of strnlen() when trying to point
to the first character after the current string.  This issue would
cause individual characters (where the 128 byte buffers are stitched
together) to be lost.

gcc/ChangeLog:

	* config/aarch64/driver-aarch64.c (readline): Fix off-by-one.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/cpunative/info_18: New test.
	* gcc.target/aarch64/cpunative/native_cpu_18.c: New test.

(cherry picked from commit b1cfbccc41de6aec950c0f662e7e85ab34bfff8a)

diff --git a/gcc/config/aarch64/driver-aarch64.c b/gcc/config/aarch64/driver-aarch64.c
index e2935a1156412c898ea086feb0d698ec92107652..5505e11751552b51f5ae0c7b459c6d3bbde718c3 100644 (file)
--- a/gcc/config/aarch64/driver-aarch64.c
+++ b/gcc/config/aarch64/driver-aarch64.c
@@ -200,9 +200,9 @@ readline (FILE *f)
        return std::string ();
       /* If we're not at the end of the line then override the
         \0 added by fgets.  */
-      last = strnlen (buf, size) - 1;
+      last = strnlen (buf, size);
     }
-  while (!feof (f) && buf[last] != '\n');
+  while (!feof (f) && last > 0 && buf[last - 1] != '\n');
 
   std::string result (buf);
   free (buf);

diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/info_18 b/gcc/testsuite/gcc.target/aarch64/cpunative/info_18
new file mode 100644 (file)
index 0000000..25061a4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/cpunative/info_18
@@ -0,0 +1,8 @@
+processor      : 0
+BogoMIPS       : 2000.00
+Features       : fp asimd evtstrm aes pmull sha1 sha2 crc32 atomics fphp asimdhp cpuid asimdrdm jscvt fcma lrcpc dcpop sha3 asimddp sha512 asimdfhm dit uscat ilrcpc flagm ssbs sb dcpodp flagm2 frint i8mm bf16 rng ecv
+CPU implementer        : 0xc0
+CPU architecture: 8
+CPU variant    : 0x0
+CPU part       : 0xac3
+CPU revision   : 0

diff --git a/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_18.c b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_18.c
new file mode 100644 (file)
index 0000000..b5f0a30
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/cpunative/native_cpu_18.c
@@ -0,0 +1,15 @@
+/* { dg-do compile { target { { aarch64*-*-linux*} && native } } } */
+/* { dg-set-compiler-env-var GCC_CPUINFO "$srcdir/gcc.target/aarch64/cpunative/info_18" } */
+/* { dg-additional-options "-mcpu=native" } */
+
+int main()
+{
+  return 0;
+}
+
+/* { dg-final { scan-assembler {\.arch armv8.6-a\+crc\+fp16\+aes\+sha3\+rng} } } */
+
+/* Test one where the boundary of buffer size would overwrite the last
+   character read when stitching the fgets-calls together.  With the
+   test data provided, this would truncate the 'sha512' into 'ha512'
+   (dropping the 'sha3' feature). */