Allow building cpufrequtils with clang

Make sure invalid assembly code isn't included even in
unreachable code; remove TOOLCHAIN=gcc workaround.

Signed-off-by: Bernhard Rosenkränzer <bernhard.rosenkraenzer.ext@huawei.com>

3 files changed, 34 insertions, 5 deletions

diff --git a/conf/nonclangable.conf b/conf/nonclangable.conf
index a51213f..a7f32d4 100644
--- a/conf/nonclangable.conf
+++ b/conf/nonclangable.conf
@@ -1,9 +1,4 @@
 TOOLCHAIN_pn-u-boot = "gcc"
-# In file included from utils/aperf.c:56:
-# utils/cpuid.h:17:8: error: invalid output constraint '=a' in asm
-#             : "=a" (*eax),
-# (seen on aarch64 with clang 12.0, cpufrequtils 008)
-TOOLCHAIN_pn-cpufrequtils = "gcc"
 # crash embeds version of gdb which is not buildable with clang
 TOOLCHAIN_pn-crash = "gcc"
 TOOLCHAIN_pn-elfutils = "gcc"
diff --git a/recipes-bsp/cpufrequtils/cpufrequtils/cpufrequtils-008-fix-build-on-non-x86.patch b/recipes-bsp/cpufrequtils/cpufrequtils/cpufrequtils-008-fix-build-on-non-x86.patch
new file mode 100644
index 0000000..0006add
--- /dev/null
+++ b/recipes-bsp/cpufrequtils/cpufrequtils/cpufrequtils-008-fix-build-on-non-x86.patch
@@ -0,0 +1,32 @@
+From: Bernhard Rosenkränzer <bernhard.rosenkraenzer.ext@huawei.com>
+Date: Thu, 27 May 2021 22:51:00 +0200
+Subject: [PATCH] utils: Fix build on non-x86 with clang
+
+Without this patch, there is an invalid asm construct (forcing EAX) on
+non-x86 architectures in unreachable code.
+
+gcc allows this (because it throws out the unreachable code before checking
+it), but clang does not.
+
+Signed-off-by: Bernhard Rosenkränzer <bernhard.rosenkraenzer.ext@huawei.com>
+Upstream-Status: Pending
+
+diff -up git/utils/cpuid.h.omv~ git/utils/cpuid.h
+--- git/utils/cpuid.h.omv~      2021-05-27 22:44:44.833614642 +0200
++++ git/utils/cpuid.h   2021-05-27 22:45:25.546050445 +0200
+@@ -1,6 +1,8 @@
+ #ifndef _CPUFREQ_CPUID_H
+ #define _CPUFREQ_CPUID_H
+ 
++#if defined(__i386__) || defined(__x86_64__)
++
+ static inline void __cpuid(unsigned int *eax, unsigned int *ebx,
+                                unsigned int *ecx, unsigned int *edx)
+ {
+@@ -72,4 +74,6 @@ static inline unsigned int cpuid_edx(uns
+        return edx;
+ }
+ 
++#endif /* i386 || x86_64 */
++
+ #endif /* _CPUFREQ_CPUID_H */
diff --git a/recipes-bsp/cpufrequtils/cpufrequtils_%.bbappend b/recipes-bsp/cpufrequtils/cpufrequtils_%.bbappend
new file mode 100644
index 0000000..3b201f1
--- /dev/null
+++ b/recipes-bsp/cpufrequtils/cpufrequtils_%.bbappend
@@ -0,0 +1,2 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"
+SRC_URI_append = " file://cpufrequtils-008-fix-build-on-non-x86.patch"