[PATCH 0/3] teach sparse about endianness

[PATCH 0/3] teach sparse about endianness

[Luc Van Oostenryck]

The goal of this series is to let sparse correctly
check macros, structures, ... endian-specific.
This is done by:
1) the introduction of a pair of option flags:
   -mbig-endian/-mlittle-endian 
2) a set of predefined macros:
   __{BIG,LITTLE}_ENDIAN__,
   __ORDER_{BIG,LITTLE}_ENDIAN__ &
   __BYTE_ORDER__

[PATCH 1/3] teach sparse about -m{big,little}-endian

[Luc Van Oostenryck]

Some macros, structures definitions, ... depends on the
endianness and thus checking them with sparse demands
that sparse is endian-aware.

Give this information to sparse with two flags:
-mbig-endian/-mlittle-endian, and by default use
the endianness of the platform used to compile sparse.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 lib.c | 15 ++++++++++++++-
 lib.h |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib.c b/lib.c
index eac84ee3f..a22635ecc 100644
--- a/lib.c
+++ b/lib.c
@@ -282,6 +282,14 @@ static enum { STANDARD_C89,
 int arch_m64 = ARCH_M64_DEFAULT;
 int arch_msize_long = 0;
 
+#ifdef __BIG_ENDIAN__
+#define ARCH_BIG_ENDIAN 1
+#else
+#define ARCH_BIG_ENDIAN 0
+#endif
+int arch_big_endian = ARCH_BIG_ENDIAN;
+
+
 #define CMDLINE_INCLUDE 20
 static int cmdline_include_nr = 0;
 static char *cmdline_include[CMDLINE_INCLUDE];
@@ -410,8 +418,13 @@ static char **handle_switch_m(char *arg, char **next)
 		arch_m64 = ARCH_LLP64;
 	} else if (!strcmp(arg, "msize-long")) {
 		arch_msize_long = 1;
-	} else if (!strcmp(arg, "multiarch-dir"))
+	} else if (!strcmp(arg, "multiarch-dir")) {
 		return handle_multiarch_dir(arg, next);
+	} else if (!strcmp(arg, "mbig-endian")) {
+		arch_big_endian = 1;
+	} else if (!strcmp(arg, "mlittle-endian")) {
+		arch_big_endian = 0;
+	}
 	return next;
 }
 
diff --git a/lib.h b/lib.h
index e09f47f12..3f8d3615a 100644
--- a/lib.h
+++ b/lib.h
@@ -150,6 +150,7 @@ extern int fdump_linearize;
 extern unsigned long long fmemcpy_max_count;
 
 extern int arch_m64;
+extern int arch_big_endian;
 
 extern void declare_builtin_functions(void);
 extern void create_builtin_stream(void);
-- 
2.13.0

[PATCH 2/3] teach sparse about __{BIG,LITTLE}_ENDIAN__

[Luc Van Oostenryck]

Some macros, structures definitions, ... depends on the
endianness. This is generaly done via some header file
but these headers need information from the compiler via
the macros __{BIG,LITTLE}_ENDIAN__.

Let sparse predefine these macros like compilers do.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 lib.c                      |  3 +++
 validation/endian-big.c    | 11 +++++++++++
 validation/endian-little.c | 11 +++++++++++
 3 files changed, 25 insertions(+)
 create mode 100644 validation/endian-big.c
 create mode 100644 validation/endian-little.c

diff --git a/lib.c b/lib.c
index a22635ecc..daf7d0219 100644
--- a/lib.c
+++ b/lib.c
@@ -961,6 +961,9 @@ static void predefined_macros(void)
 	predefined_sizeof("FLOAT", bits_in_float);
 	predefined_sizeof("DOUBLE", bits_in_double);
 	predefined_sizeof("LONG_DOUBLE", bits_in_longdouble);
+
+	add_pre_buffer("#weak_define __%s_ENDIAN__ 1\n",
+		arch_big_endian ? "BIG" : "LITTLE");
 }
 
 void declare_builtin_functions(void)
diff --git a/validation/endian-big.c b/validation/endian-big.c
new file mode 100644
index 000000000..d535748cd
--- /dev/null
+++ b/validation/endian-big.c
@@ -0,0 +1,11 @@
+#if defined(__LITTLE_ENDIAN__)
+#error "__LITTLE_ENDIAN__ defined!"
+#endif
+#if (__BIG_ENDIAN__ != 1)
+#error "__BIG_ENDIAN__ not correctly defined!"
+#endif
+
+/*
+ * check-name: endian-big.c
+ * check-command: sparse -mbig-endian $file
+ */
diff --git a/validation/endian-little.c b/validation/endian-little.c
new file mode 100644
index 000000000..cc4a14f73
--- /dev/null
+++ b/validation/endian-little.c
@@ -0,0 +1,11 @@
+#if defined(__BIG_ENDIAN__)
+#error "__BIG_ENDIAN__ defined!"
+#endif
+#if (__LITTLE_ENDIAN__ != 1)
+#error "__LITTLE_ENDIAN__ not correctly defined!"
+#endif
+
+/*
+ * check-name: endian-little.c
+ * check-command: sparse -mlittle-endian $file
+ */
-- 
2.13.0

[PATCH 3/3] teach sparse about __BYTE_ORDER__ & __ORDER_{BIG,LITTLE}_ENDIAN__

[Luc Van Oostenryck]

Some macros, structures definitions, ... depends on the
endianness. This is generaly done via some header file
but these headers need information from the compiler via
the macros __BYTE_ORDER__, itself being defined to
__ORDER_BIG_ENDIAN__ or __ORDER_LITTLE_ENDIAN__.

Let sparse predefine these macros like compilers do.

Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
---
 lib.c                      | 6 ++++++
 validation/endian-big.c    | 3 +++
 validation/endian-little.c | 3 +++
 3 files changed, 12 insertions(+)

diff --git a/lib.c b/lib.c
index daf7d0219..de6350439 100644
--- a/lib.c
+++ b/lib.c
@@ -964,6 +964,12 @@ static void predefined_macros(void)
 
 	add_pre_buffer("#weak_define __%s_ENDIAN__ 1\n",
 		arch_big_endian ? "BIG" : "LITTLE");
+
+	add_pre_buffer("#weak_define __ORDER_LITTLE_ENDIAN__ 1234\n");
+	add_pre_buffer("#weak_define __ORDER_BIG_ENDIAN__ 4321\n");
+	add_pre_buffer("#weak_define __ORDER_PDP_ENDIAN__ 3412\n");
+	add_pre_buffer("#weak_define __BYTE_ORDER__ __ORDER_%s_ENDIAN__\n",
+		arch_big_endian ? "BIG" : "LITTLE");
 }
 
 void declare_builtin_functions(void)
diff --git a/validation/endian-big.c b/validation/endian-big.c
index d535748cd..ebf95df70 100644
--- a/validation/endian-big.c
+++ b/validation/endian-big.c
@@ -4,6 +4,9 @@
 #if (__BIG_ENDIAN__ != 1)
 #error "__BIG_ENDIAN__ not correctly defined!"
 #endif
+#if (__BYTE_ORDER__ != __ORDER_BIG_ENDIAN__)
+#error "__BYTE_ORDER__ not correctly defined!"
+#endif
 
 /*
  * check-name: endian-big.c
diff --git a/validation/endian-little.c b/validation/endian-little.c
index cc4a14f73..57ef69866 100644
--- a/validation/endian-little.c
+++ b/validation/endian-little.c
@@ -4,6 +4,9 @@
 #if (__LITTLE_ENDIAN__ != 1)
 #error "__LITTLE_ENDIAN__ not correctly defined!"
 #endif
+#if (__BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__)
+#error "__BYTE_ORDER__ not correctly defined!"
+#endif
 
 /*
  * check-name: endian-little.c
-- 
2.13.0

Re: [PATCH 0/3] teach sparse about endianness

[Christopher Li]

On Tue, Jun 20, 2017 at 1:19 PM, Luc Van Oostenryck
<luc.vanoostenryck@gmail.com> wrote:
> The goal of this series is to let sparse correctly
> check macros, structures, ... endian-specific.
> This is done by:
> 1) the introduction of a pair of option flags:
>    -mbig-endian/-mlittle-endian
> 2) a set of predefined macros:
>    __{BIG,LITTLE}_ENDIAN__,
>    __ORDER_{BIG,LITTLE}_ENDIAN__ &
>    __BYTE_ORDER__

This series looks good to me.

Signed-off-By: <sparse@chrisli.org>

Chris