Kbuild fixes for v5.9 (4th)

- Ignore compiler stubs for PPC to fix builds
 
  - Fix the usage of --target mentioned in the LLVM document
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Merge tag 'kbuild-fixes-v5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

 - ignore compiler stubs for PPC to fix builds

 - fix the usage of --target mentioned in the LLVM document

* tag 'kbuild-fixes-v5.9-4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  Documentation/llvm: Fix clang target examples
  scripts/kallsyms: skip ppc compiler stub *.long_branch.* / *.plt_branch.*

Documentation/kbuild/llvm.rst

@@ -39,10 +39,10 @@ which can help simplify cross compiling. ::
 	ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make CC=clang
 
 ``CROSS_COMPILE`` is not used to prefix the Clang compiler binary, instead
-``CROSS_COMPILE`` is used to set a command line flag: ``--target <triple>``. For
+``CROSS_COMPILE`` is used to set a command line flag: ``--target=<triple>``. For
 example: ::
 
-	clang --target aarch64-linux-gnu foo.c
+	clang --target=aarch64-linux-gnu foo.c
 
 LLVM Utilities
 --------------

scripts/kallsyms.c

@@ -82,6 +82,7 @@ static char *sym_name(const struct sym_entry *s)
 
 static bool is_ignored_symbol(const char *name, char type)
 {
+	/* Symbol names that exactly match to the following are ignored.*/
 	static const char * const ignored_symbols[] = {
 		/*
 		 * Symbols which vary between passes. Passes 1 and 2 must have
@@ -104,6 +105,7 @@ static bool is_ignored_symbol(const char *name, char type)
 		NULL
 	};
 
+	/* Symbol names that begin with the following are ignored.*/
 	static const char * const ignored_prefixes[] = {
 		"$",			/* local symbols for ARM, MIPS, etc. */
 		".LASANPC",		/* s390 kasan local symbols */
@@ -113,6 +115,7 @@ static bool is_ignored_symbol(const char *name, char type)
 		NULL
 	};
 
+	/* Symbol names that end with the following are ignored.*/
 	static const char * const ignored_suffixes[] = {
 		"_from_arm",		/* arm */
 		"_from_thumb",		/* arm */
@@ -120,9 +123,15 @@ static bool is_ignored_symbol(const char *name, char type)
 		NULL
 	};
 
+	/* Symbol names that contain the following are ignored.*/
+	static const char * const ignored_matches[] = {
+		".long_branch.",	/* ppc stub */
+		".plt_branch.",		/* ppc stub */
+		NULL
+	};
+
 	const char * const *p;
 
-	/* Exclude symbols which vary between passes. */
 	for (p = ignored_symbols; *p; p++)
 		if (!strcmp(name, *p))
 			return true;
@@ -138,6 +147,11 @@ static bool is_ignored_symbol(const char *name, char type)
 			return true;
 	}
 
+	for (p = ignored_matches; *p; p++) {
+		if (strstr(name, *p))
+			return true;
+	}
+
 	if (type == 'U' || type == 'u')
 		return true;
 	/* exclude debugging symbols */