Darwin : Update the kernel version to macOS version mapping.

With the change to macOS 11 and Darwin20, the algorithm for mapping
kernel version to macOS version has changed.

We now have darwin 20.X.Y => macOS 11.(X > 0 ? X - 1 : 0).??.
It currently unclear if the Y will be mapped to macOS patch version
and, if so, whether it will be one-based or 0-based.
Likewise, it's unknown if Darwin 21 will map to macOS 12, so these
entries are unchanged for the present.

gcc/ChangeLog:

	* config/darwin-driver.c (darwin_find_version_from_kernel):
	Compute the minor OS version from the minor kernel version.

diff --git a/gcc/config/darwin-driver.c b/gcc/config/darwin-driver.c
index 8ae300057fd36a3ab0a187a75a2502ec82aa3f3f..4a9426ef273797d7d12f1912d619d19346165915 100644 (file)
--- a/gcc/config/darwin-driver.c
+++ b/gcc/config/darwin-driver.c
@@ -149,9 +149,22 @@ darwin_find_version_from_kernel (void)
   if (*version_p++ != '.')
     goto parse_failed;
 
-  /* Darwin20 sees a transition to macOS 11.  */
+  /* Darwin20 sees a transition to macOS 11.  In this, it seems that the
+     mapping to macOS minor version is now shifted to the kernel minor
+     version - 1 (at least for the initial releases).  At this stage, we
+     don't know what macOS version will correspond to Darwin21.  */
   if (major_vers >= 20)
-    asprintf (&new_flag, "11.%02d.00", major_vers - 20);
+    {
+      int minor_vers = *version_p++ - '0';
+      if (ISDIGIT (*version_p))
+       minor_vers = minor_vers * 10 + (*version_p++ - '0');
+      if (*version_p++ != '.')
+       goto parse_failed;
+      if (minor_vers > 0)
+       minor_vers -= 1; /* Kernel 20.3 => macOS 11.2.  */
+      /* It's not yet clear whether patch level will be considered.  */
+      asprintf (&new_flag, "11.%02d.00", minor_vers);
+    }
   else if (major_vers - 4 <= 4)
     /* On 10.4 and earlier, the old linker is used which does not
        support three-component system versions.