Auto-generate libc-modules.h

Remove libc-modules.h from the tree and auto-generate it from
soversions.i and the list of modules in the built-modules variable
defined in Makeconfig.  Macros generated have increasing numbered
values, with built-modules having lower values starting from 1,
following which a separator value LIBS_BEGIN is added and then finally
the library names from soversions.i are appended to the list.  This
allows us to conveniently differentiate between the versioned
libraries and other built modules, which is needed in errno.h and
netdb.h to decide whether to use an internal symbol or an external
one.

Verified that generated code remains unchanged on x86_64.

	* Makeconfig (built-modules): List non-library modules to be
	built.
	(module-cppflags): Include libc-modules.h for
	everything except shlib-versions.v.i.
	(CPPFLAGS): Use it.
	(before-compile): Add libc-modules.h.
	($(common-objpfx)libc-modules.h,
	$(common-objpfx)libc-modules.stmp): New targets.
	(common-generated): Add libc-modules.h and libc-modules.stmp.
	($(common-objpfx)Versions.v.i): Depend on libc-modules.h.
	* include/libc-symbols.h: Don't include libc-modules.h.
	* include/libc-modules.h: Remove file.
	* scripts/gen-libc-modules.awk: New script to generate
	libc-modules.h.
	* sysdeps/unix/Makefile ($(common-objpfx)sysd-syscalls):
	Depend on libc-modules.stmp.

1 files changed, 34 insertions, 0 deletions

diff --git a/scripts/gen-libc-modules.awk b/scripts/gen-libc-modules.awk
new file mode 100644
index 0000000000..2f92cd41b2
--- /dev/null
+++ b/scripts/gen-libc-modules.awk
@@ -0,0 +1,34 @@
+# Generate a header file that defines the MODULE_* macros for each library and
+# module we build in glibc.  The library names are pulled in from soversions.i
+# and the additional modules are passed in the BUILDLIST variable.
+BEGIN {
+  # BUILDLIST is set from the build-list variable in Makeconfig and is a space
+  # separated list of non-library modules that we build in glibc.
+  num = split (buildlist, libs, " ")
+  # Separate the built modules from the libraries.
+  libs[++num] = "LIBS_BEGIN"
+}
+
+# Skip over comments.
+$1 == "#" {
+  next
+}
+
+# We have only one special case in soversions.i parsing, which is to replace ld
+# with rtld since that's what we call it throughout the sources.
+match (FILENAME, ".*soversions.i") {
+  name = $2
+  if (name == "ld")
+    name = "rtld"
+
+  # Library names are not duplicated in soversions.i.
+  libs[++num] = name
+}
+
+# Finally, print out the header file.
+END {
+  printf ("/* AUTOGENERATED BY gen-libc-modules.awk, DO NOT EDIT.  */\n\n")
+  for (l in libs) {
+    printf ("#define MODULE_%s %d\n", libs[l], l)
+  }
+}