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Subject[PATCH 1/1] libbpf: fix broken gcc pragma macros in bpf_helpers.h/bpf_tracing.h
Date
It seems the gcc preprocessor breaks unless pragmas are wrapped
individually inside macros.

Fixes errors like:
error: expected identifier or '(' before '#pragma'
106 | SEC("cgroup/bind6")
| ^~~

error: expected '=', ',', ';', 'asm' or '__attribute__' before '#pragma'
114 | char _license[] SEC("license") = "GPL";
| ^~~

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
---
tools/lib/bpf/bpf_helpers.h | 26 ++++++++++++++------------
tools/lib/bpf/bpf_tracing.h | 26 ++++++++++++++------------
2 files changed, 28 insertions(+), 24 deletions(-)

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index fb04eaf367f1..6d159082727d 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -22,11 +22,13 @@
* To allow use of SEC() with externs (e.g., for extern .maps declarations),
* make sure __attribute__((unused)) doesn't trigger compilation warning.
*/
+#define __gcc_helpers_pragma(x) _Pragma(#x)
+#define __gcc_helpers_diag_pragma(x) __gcc_helpers_pragma("GCC diagnostic " #x)
#define SEC(name) \
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \
+ __gcc_helpers_diag_pragma(push) \
+ __gcc_helpers_diag_pragma(ignored "-Wignored-attributes") \
__attribute__((section(name), used)) \
- _Pragma("GCC diagnostic pop") \
+ __gcc_helpers_diag_pragma(pop)

/* Avoid 'linux/stddef.h' definition of '__always_inline'. */
#undef __always_inline
@@ -215,10 +217,10 @@ enum libbpf_tristate {
static const char ___fmt[] = fmt; \
unsigned long long ___param[___bpf_narg(args)]; \
\
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_helpers_diag_pragma(push) \
+ __gcc_helpers_diag_pragma(ignored "-Wint-conversion") \
___bpf_fill(___param, args); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_helpers_diag_pragma(pop) \
\
bpf_seq_printf(seq, ___fmt, sizeof(___fmt), \
___param, sizeof(___param)); \
@@ -233,10 +235,10 @@ enum libbpf_tristate {
static const char ___fmt[] = fmt; \
unsigned long long ___param[___bpf_narg(args)]; \
\
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_helpers_diag_pragma(push) \
+ __gcc_helpers_diag_pragma(ignored "-Wint-conversion") \
___bpf_fill(___param, args); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_helpers_diag_pragma(pop) \
\
bpf_snprintf(out, out_size, ___fmt, \
___param, sizeof(___param)); \
@@ -264,10 +266,10 @@ enum libbpf_tristate {
static const char ___fmt[] = fmt; \
unsigned long long ___param[___bpf_narg(args)]; \
\
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_helpers_diag_pragma(push) \
+ __gcc_helpers_diag_pragma(ignored "-Wint-conversion") \
___bpf_fill(___param, args); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_helpers_diag_pragma(pop) \
\
bpf_trace_vprintk(___fmt, sizeof(___fmt), \
___param, sizeof(___param)); \
diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
index 01ce121c302d..e08ffc290b3e 100644
--- a/tools/lib/bpf/bpf_tracing.h
+++ b/tools/lib/bpf/bpf_tracing.h
@@ -422,16 +422,18 @@ struct pt_regs;
* This is useful when using BPF helpers that expect original context
* as one of the parameters (e.g., for bpf_perf_event_output()).
*/
+#define __gcc_tracing_pragma(x) _Pragma(#x)
+#define __gcc_tracing_diag_pragma(x) __gcc_tracing_pragma("GCC diagnostic " #x)
#define BPF_PROG(name, args...) \
name(unsigned long long *ctx); \
static __attribute__((always_inline)) typeof(name(0)) \
____##name(unsigned long long *ctx, ##args); \
typeof(name(0)) name(unsigned long long *ctx) \
{ \
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_tracing_diag_pragma(push) \
+ __gcc_tracing_diag_pragma(ignored "-Wint-conversion") \
return ____##name(___bpf_ctx_cast(args)); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_tracing_diag_pragma(pop) \
} \
static __attribute__((always_inline)) typeof(name(0)) \
____##name(unsigned long long *ctx, ##args)
@@ -462,10 +464,10 @@ static __attribute__((always_inline)) typeof(name(0)) \
____##name(struct pt_regs *ctx, ##args); \
typeof(name(0)) name(struct pt_regs *ctx) \
{ \
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_tracing_diag_pragma(push) \
+ __gcc_tracing_diag_pragma(ignored "-Wint-conversion") \
return ____##name(___bpf_kprobe_args(args)); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_tracing_diag_pragma(pop) \
} \
static __attribute__((always_inline)) typeof(name(0)) \
____##name(struct pt_regs *ctx, ##args)
@@ -486,10 +488,10 @@ static __attribute__((always_inline)) typeof(name(0)) \
____##name(struct pt_regs *ctx, ##args); \
typeof(name(0)) name(struct pt_regs *ctx) \
{ \
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_tracing_diag_pragma(push) \
+ __gcc_tracing_diag_pragma(ignored "-Wint-conversion") \
return ____##name(___bpf_kretprobe_args(args)); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_tracing_diag_pragma(pop) \
} \
static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)

@@ -520,10 +522,10 @@ ____##name(struct pt_regs *ctx, ##args); \
typeof(name(0)) name(struct pt_regs *ctx) \
{ \
struct pt_regs *regs = PT_REGS_SYSCALL_REGS(ctx); \
- _Pragma("GCC diagnostic push") \
- _Pragma("GCC diagnostic ignored \"-Wint-conversion\"") \
+ __gcc_tracing_diag_pragma(push) \
+ __gcc_tracing_diag_pragma(ignored "-Wint-conversion") \
return ____##name(___bpf_syscall_args(args)); \
- _Pragma("GCC diagnostic pop") \
+ __gcc_tracing_diag_pragma(pop) \
} \
static __attribute__((always_inline)) typeof(name(0)) \
____##name(struct pt_regs *ctx, ##args)
--
2.25.1
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