Merge tag 'llvmlinux-for-v3.15' of git://git.linuxfoundation.org/llvmlinux/kernel

Pull llvm patches from Behan Webster: "These are some initial updates to support compiling the kernel with clang. These patches have been through the proper reviews to the best of my ability, and have been soaking in linux-next for a few weeks. These patches by themselves still do not completely allow clang to be used with the kernel code, but lay the foundation for other patches which are still under review. Several other of the LLVMLinux patches have been already added via maintainer trees" * tag 'llvmlinux-for-v3.15' of git://git.linuxfoundation.org/llvmlinux/kernel: x86: LLVMLinux: Fix "incomplete type const struct x86cpu_device_id" x86 kbuild: LLVMLinux: More cc-options added for clang x86, acpi: LLVMLinux: Remove nested functions from Thinkpad ACPI LLVMLinux: Add support for clang to compiler.h and new compiler-clang.h LLVMLinux: Remove warning about returning an uninitialized variable kbuild: LLVMLinux: Fix LINUX_COMPILER definition script for compilation with clang Documentation: LLVMLinux: Update Documentation/dontdiff kbuild: LLVMLinux: Adapt warnings for compilation with clang kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang

Merge tag 'llvmlinux-for-v3.15' of git://git.linuxfoundation.org/llvmlinux/kernel
Pull llvm patches from Behan Webster: "These are some initial updates to support compiling the kernel with clang. These patches have been through the proper reviews to the best of my ability, and have been soaking in linux-next for a few weeks. These patches by themselves still do not completely allow clang to be used with the kernel code, but lay the foundation for other patches which are still under review. Several other of the LLVMLinux patches have been already added via maintainer trees" * tag 'llvmlinux-for-v3.15' of git://git.linuxfoundation.org/llvmlinux/kernel: x86: LLVMLinux: Fix "incomplete type const struct x86cpu_device_id" x86 kbuild: LLVMLinux: More cc-options added for clang x86, acpi: LLVMLinux: Remove nested functions from Thinkpad ACPI LLVMLinux: Add support for clang to compiler.h and new compiler-clang.h LLVMLinux: Remove warning about returning an uninitialized variable kbuild: LLVMLinux: Fix LINUX_COMPILER definition script for compilation with clang Documentation: LLVMLinux: Update Documentation/dontdiff kbuild: LLVMLinux: Adapt warnings for compilation with clang kbuild: LLVMLinux: Add Kbuild support for building kernel with Clang
Linus Torvalds
2 parents 141eaccd01 c4586256f0
Showing 9 changed files Side-by-side Diff
Documentation/dontdiff
Makefile
arch/x86/Makefile
include/asm-generic/cmpxchg-local.h
include/linux/compiler-clang.h
include/linux/compiler.h
include/linux/mod_devicetable.h
scripts/Makefile.build
scripts/mkcompile_h
 *.a
 *.aux
+*.bc
 *.bin
 *.bz2
 *.cis
@@ -21,6 +22,7 @@
 *.i
 *.jpeg
 *.ko
+*.ll
 *.log
 *.lst
 *.lzma
@@ -35,6 +37,7 @@
 *.out
 *.patch
 *.pdf
+*.plist
 *.png
 *.pot
 *.ps
@@ -248,6 +248,11 @@
 HOSTCFLAGS   = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer
 HOSTCXXFLAGS = -O2
  
+ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1)
+HOSTCFLAGS  += -Wno-unused-value -Wno-unused-parameter \
+		-Wno-missing-field-initializers -fno-delete-null-pointer-checks
+endif
+
 # Decide whether to build built-in, modular, or both.
 # Normally, just do built-in.
  
@@ -324,6 +329,14 @@
  
 export quiet Q KBUILD_VERBOSE
  
+ifneq ($(CC),)
+ifeq ($(shell $(CC) -v 2>&1 | grep -c "clang version"), 1)
+COMPILER := clang
+else
+COMPILER := gcc
+endif
+export COMPILER
+endif
  
 # Look for make include files relative to root of kernel src
 MAKEFLAGS += --include-dir=$(srctree)
@@ -383,7 +396,7 @@
 		   -fno-strict-aliasing -fno-common \
 		   -Werror-implicit-function-declaration \
 		   -Wno-format-security \
-		   -fno-delete-null-pointer-checks
+		   $(call cc-option,-fno-delete-null-pointer-checks,)
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
 KBUILD_AFLAGS   := -D__ASSEMBLY__
  
@@ -623,9 +636,24 @@
 endif
 KBUILD_CFLAGS += $(stackp-flag)
  
+ifeq ($(COMPILER),clang)
+KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
+KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)
+KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
+KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
+KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
+# Quiet clang warning: comparison of unsigned expression < 0 is always false
+KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
+# CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
+# source of a reference will be _MergedGlobals and not on of the whitelisted names.
+# See modpost pattern 2
+KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,)
+else
+
 # This warning generated too much noise in a regular build.
 # Use make W=1 to enable this warning (see scripts/Makefile.build)
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
+endif
  
 ifdef CONFIG_FRAME_POINTER
 KBUILD_CFLAGS	+= -fno-omit-frame-pointer -fno-optimize-sibling-calls
@@ -108,7 +108,7 @@
  
         # this works around some issues with generating unwind tables in older gccs
         # newer gccs do it by default
-        KBUILD_CFLAGS += -maccumulate-outgoing-args
+        KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args)
 endif
  
 # Make sure compiler does not have buggy stack-protector support.
@@ -4,7 +4,8 @@
 #include <linux/types.h>
 #include <linux/irqflags.h>
  
-extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
+extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
+	__noreturn;
  
 /*
  * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
+#endif
+
+/* Some compiler specific definitions are overwritten here
+ * for Clang compiler
+ */
+
+#ifdef uninitialized_var
+#undef uninitialized_var
+#define uninitialized_var(x) x = *(&(x))
+#endif
@@ -63,6 +63,13 @@
 # include <linux/compiler-intel.h>
 #endif
  
+/* Clang compiler defines __GNUC__. So we will overwrite implementations
+ * coming from above header files here
+ */
+#ifdef __clang__
+#include <linux/compiler-clang.h>
+#endif
+
 /*
  * Generic compiler-dependent macros required for kernel
  * build go below this comment. Actual compiler/compiler version
@@ -556,6 +556,11 @@
  * See documentation of "x86_match_cpu" for details.
  */
  
+/*
+ * MODULE_DEVICE_TABLE expects this struct to be called x86cpu_device_id.
+ * Although gcc seems to ignore this error, clang fails without this define.
+ */
+#define x86cpu_device_id x86_cpu_id
 struct x86_cpu_id {
 	__u16 vendor;
 	__u16 family;
@@ -65,11 +65,21 @@
 warning-1 := -Wextra -Wunused -Wno-unused-parameter
 warning-1 += -Wmissing-declarations
 warning-1 += -Wmissing-format-attribute
-warning-1 += -Wmissing-prototypes
+warning-1 += $(call cc-option, -Wmissing-prototypes)
 warning-1 += -Wold-style-definition
 warning-1 += $(call cc-option, -Wmissing-include-dirs)
 warning-1 += $(call cc-option, -Wunused-but-set-variable)
 warning-1 += $(call cc-disable-warning, missing-field-initializers)
+
+# Clang
+warning-1 += $(call cc-disable-warning, initializer-overrides)
+warning-1 += $(call cc-disable-warning, unused-value)
+warning-1 += $(call cc-disable-warning, format)
+warning-1 += $(call cc-disable-warning, unknown-warning-option)
+warning-1 += $(call cc-disable-warning, sign-compare)
+warning-1 += $(call cc-disable-warning, format-zero-length)
+warning-1 += $(call cc-disable-warning, uninitialized)
+warning-1 += $(call cc-option, -fcatch-undefined-behavior)
  
 warning-2 := -Waggregate-return
 warning-2 += -Wcast-align
@@ -76,7 +76,7 @@
   echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY | $UTS_TRUNCATE`\"
   echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST | $UTS_TRUNCATE`\"
  
-  echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | tail -n 1`\"
+  echo \#define LINUX_COMPILER \"`$CC -v 2>&1 | grep ' version '`\"
 ) > .tmpcompile
  
 # Only replace the real compile.h if the new one is different,
1	1	*.a
2	2	*.aux
	3	+*.bc
3	4	*.bin
4	5	*.bz2
5	6	*.cis
...	...	@@ -21,6 +22,7 @@
21	22	*.i
22	23	*.jpeg
23	24	*.ko
	25	+*.ll
24	26	*.log
25	27	*.lst
26	28	*.lzma
...	...	@@ -35,6 +37,7 @@
35	37	*.out
36	38	*.patch
37	39	*.pdf
	40	+*.plist
38	41	*.png
39	42	*.pot
40	43	*.ps
...	...	@@ -248,6 +248,11 @@
248	248	HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer
249	249	HOSTCXXFLAGS = -O2
250	250
	251	+ifeq ($(shell $(HOSTCC) -v 2>&1 \| grep -c "clang version"), 1)
	252	+HOSTCFLAGS += -Wno-unused-value -Wno-unused-parameter \
	253	+ -Wno-missing-field-initializers -fno-delete-null-pointer-checks
	254	+endif
	255	+
251	256	# Decide whether to build built-in, modular, or both.
252	257	# Normally, just do built-in.
253	258
...	...	@@ -324,6 +329,14 @@
324	329
325	330	export quiet Q KBUILD_VERBOSE
326	331
	332	+ifneq ($(CC),)
	333	+ifeq ($(shell $(CC) -v 2>&1 \| grep -c "clang version"), 1)
	334	+COMPILER := clang
	335	+else
	336	+COMPILER := gcc
	337	+endif
	338	+export COMPILER
	339	+endif
327	340
328	341	# Look for make include files relative to root of kernel src
329	342	MAKEFLAGS += --include-dir=$(srctree)
...	...	@@ -383,7 +396,7 @@
383	396	-fno-strict-aliasing -fno-common \
384	397	-Werror-implicit-function-declaration \
385	398	-Wno-format-security \
386		- -fno-delete-null-pointer-checks
	399	+ $(call cc-option,-fno-delete-null-pointer-checks,)
387	400	KBUILD_AFLAGS_KERNEL :=
388	401	KBUILD_CFLAGS_KERNEL :=
389	402	KBUILD_AFLAGS := -D__ASSEMBLY__
390	403
...	...	@@ -623,9 +636,24 @@
623	636	endif
624	637	KBUILD_CFLAGS += $(stackp-flag)
625	638
	639	+ifeq ($(COMPILER),clang)
	640	+KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
	641	+KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,)
	642	+KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
	643	+KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
	644	+KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
	645	+# Quiet clang warning: comparison of unsigned expression < 0 is always false
	646	+KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
	647	+# CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the
	648	+# source of a reference will be _MergedGlobals and not on of the whitelisted names.
	649	+# See modpost pattern 2
	650	+KBUILD_CFLAGS += $(call cc-option, -mno-global-merge,)
	651	+else
	652	+
626	653	# This warning generated too much noise in a regular build.
627	654	# Use make W=1 to enable this warning (see scripts/Makefile.build)
628	655	KBUILD_CFLAGS += $(call cc-disable-warning, unused-but-set-variable)
	656	+endif
629	657
630	658	ifdef CONFIG_FRAME_POINTER
631	659	KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
...	...	@@ -108,7 +108,7 @@
108	108
109	109	# this works around some issues with generating unwind tables in older gccs
110	110	# newer gccs do it by default
111		- KBUILD_CFLAGS += -maccumulate-outgoing-args
	111	+ KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args)
112	112	endif
113	113
114	114	# Make sure compiler does not have buggy stack-protector support.
...	...	@@ -4,7 +4,8 @@
4	4	#include <linux/types.h>
5	5	#include <linux/irqflags.h>
6	6
7		-extern unsigned long wrong_size_cmpxchg(volatile void *ptr);
	7	+extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
	8	+ __noreturn;
8	9
9	10	/*
10	11	* Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
	1	+#ifndef __LINUX_COMPILER_H
	2	+#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
	3	+#endif
	4	+
	5	+/* Some compiler specific definitions are overwritten here
	6	+ * for Clang compiler
	7	+ */
	8	+
	9	+#ifdef uninitialized_var
	10	+#undef uninitialized_var
	11	+#define uninitialized_var(x) x = *(&(x))
	12	+#endif
...	...	@@ -63,6 +63,13 @@
63	63	# include <linux/compiler-intel.h>
64	64	#endif
65	65
	66	+/* Clang compiler defines __GNUC__. So we will overwrite implementations
	67	+ * coming from above header files here
	68	+ */
	69	+#ifdef __clang__
	70	+#include <linux/compiler-clang.h>
	71	+#endif
	72	+
66	73	/*
67	74	* Generic compiler-dependent macros required for kernel
68	75	* build go below this comment. Actual compiler/compiler version
...	...	@@ -556,6 +556,11 @@
556	556	* See documentation of "x86_match_cpu" for details.
557	557	*/
558	558
	559	+/*
	560	+ * MODULE_DEVICE_TABLE expects this struct to be called x86cpu_device_id.
	561	+ * Although gcc seems to ignore this error, clang fails without this define.
	562	+ */
	563	+#define x86cpu_device_id x86_cpu_id
559	564	struct x86_cpu_id {
560	565	__u16 vendor;
561	566	__u16 family;
...	...	@@ -65,11 +65,21 @@
65	65	warning-1 := -Wextra -Wunused -Wno-unused-parameter
66	66	warning-1 += -Wmissing-declarations
67	67	warning-1 += -Wmissing-format-attribute
68		-warning-1 += -Wmissing-prototypes
	68	+warning-1 += $(call cc-option, -Wmissing-prototypes)
69	69	warning-1 += -Wold-style-definition
70	70	warning-1 += $(call cc-option, -Wmissing-include-dirs)
71	71	warning-1 += $(call cc-option, -Wunused-but-set-variable)
72	72	warning-1 += $(call cc-disable-warning, missing-field-initializers)
	73	+
	74	+# Clang
	75	+warning-1 += $(call cc-disable-warning, initializer-overrides)
	76	+warning-1 += $(call cc-disable-warning, unused-value)
	77	+warning-1 += $(call cc-disable-warning, format)
	78	+warning-1 += $(call cc-disable-warning, unknown-warning-option)
	79	+warning-1 += $(call cc-disable-warning, sign-compare)
	80	+warning-1 += $(call cc-disable-warning, format-zero-length)
	81	+warning-1 += $(call cc-disable-warning, uninitialized)
	82	+warning-1 += $(call cc-option, -fcatch-undefined-behavior)
73	83
74	84	warning-2 := -Waggregate-return
75	85	warning-2 += -Wcast-align
...	...	@@ -76,7 +76,7 @@
76	76	echo \#define LINUX_COMPILE_BY \"`echo $LINUX_COMPILE_BY \| $UTS_TRUNCATE`\"
77	77	echo \#define LINUX_COMPILE_HOST \"`echo $LINUX_COMPILE_HOST \| $UTS_TRUNCATE`\"
78	78
79		- echo \#define LINUX_COMPILER \"`$CC -v 2>&1 \| tail -n 1`\"
	79	+ echo \#define LINUX_COMPILER \"`$CC -v 2>&1 \| grep ' version '`\"
80	80	) > .tmpcompile
81	81
82	82	# Only replace the real compile.h if the new one is different,