[PATCH 1/6] tools/build: Allow versioning of all LLVM tools defined in Makefile.include

[James Clark <james.clark@linaro.org>]

The version of LLVM tools can be given on the build command with
LLVM=-15, but this isn't applied to all tools. For example $(CC) gets
versioned, but $(CLANG) doesn't. This causes a Perf build with LTO=1 to
fail with an error about mixed clang versions:

 ld.lld: error: libperf/core.o: Unknown attribute kind (86)
   (Producer: 'LLVM18.1.8' Reader: 'LLVM 15.0.7')

This file has two "ifneq ($(LLVM),)" blocks adjacent to each other, so
merge these blocks making it obvious that all tools should be versioned
consistently and there is nothing special about each block.

This also reveals that ?= and "allow-override" are used inconsistently
between the blocks. "allow-override" is technically only required for
builtin variables, but isn't only used on them, and doesn't do any harm
if used on a non-builtin. Make them all "allow-override" for
consistency. The only functional difference this will cause is if there
is a file level definition of one of the variables followed by an
"#include of Makefile.include" which will now overwrite. But this isn't
done and in a later commit some of the duplicate definitions will be
removed for good measure.

There are also some other LLVM tools that are not defined here and will
be moved in a later commit.

Signed-off-by: James Clark <james.clark@linaro.org>
---
 tools/scripts/Makefile.include | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 41971a68972d..7022e78208a2 100644
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -61,10 +61,18 @@ $(error Invalid value for LLVM, see Documentation/kbuild/llvm.rst)
 endif
 
 $(call allow-override,CC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
+$(call allow-override,CLANG,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
+$(call allow-override,HOSTCC,$(LLVM_PREFIX)clang$(LLVM_SUFFIX))
 $(call allow-override,AR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))
+$(call allow-override,HOSTAR,$(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX))
 $(call allow-override,LD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))
+$(call allow-override,HOSTLD,$(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX))
 $(call allow-override,CXX,$(LLVM_PREFIX)clang++$(LLVM_SUFFIX))
 $(call allow-override,STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))
+$(call allow-override,LLVM_STRIP,$(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX))
+$(call allow-override,LLC,$(LLVM_PREFIX)llc$(LLVM_SUFFIX))
+$(call allow-override,LLVM_CONFIG,$(LLVM_PREFIX)llvm-config$(LLVM_SUFFIX))
+$(call allow-override,LLVM_OBJCOPY,$(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX))
 else
 # Allow setting various cross-compile vars or setting CROSS_COMPILE as a prefix.
 $(call allow-override,CC,$(CROSS_COMPILE)gcc)
@@ -72,26 +80,21 @@ $(call allow-override,AR,$(CROSS_COMPILE)ar)
 $(call allow-override,LD,$(CROSS_COMPILE)ld)
 $(call allow-override,CXX,$(CROSS_COMPILE)g++)
 $(call allow-override,STRIP,$(CROSS_COMPILE)strip)
-endif
-
-CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
 
-ifneq ($(LLVM),)
-HOSTAR  ?= $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
-HOSTCC  ?= $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
-HOSTLD  ?= $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
-else
-HOSTAR  ?= ar
-HOSTCC  ?= gcc
-HOSTLD  ?= ld
+# Host versions aren't prefixed
+$(call allow-override,HOSTAR,ar)
+$(call allow-override,HOSTCC,gcc)
+$(call allow-override,HOSTLD,ld)
+
+# Some tools still require Clang, LLC and/or LLVM utils
+$(call allow-override,CLANG,clang)
+$(call allow-override,LLC,llc)
+$(call allow-override,LLVM_CONFIG,llvm-config)
+$(call allow-override,LLVM_OBJCOPY,llvm-objcopy)
+$(call allow-override,LLVM_STRIP,llvm-strip)
 endif
 
-# Some tools require Clang, LLC and/or LLVM utils
-CLANG		?= clang
-LLC		?= llc
-LLVM_CONFIG	?= llvm-config
-LLVM_OBJCOPY	?= llvm-objcopy
-LLVM_STRIP	?= llvm-strip
+CC_NO_CLANG := $(shell $(CC) -dM -E -x c /dev/null | grep -Fq "__clang__"; echo $$?)
 
 # Some tools require bpftool
 SYSTEM_BPFTOOL	?= bpftool

-- 
2.34.1