[PATCH v5] perf tools: Fix arm64 build error with gcc-11

[Jianlin Lv]

gcc version: 11.0.0 20210208 (experimental) (GCC)

Following build error on arm64:

.......
In function ‘printf’,
    inlined from ‘regs_dump__printf’ at util/session.c:1141:3,
    inlined from ‘regs__printf’ at util/session.c:1169:2:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:107:10: \
  error: ‘%-5s’ directive argument is null [-Werror=format-overflow=]

107 |   return __printf_chk (__USE_FORTIFY_LEVEL - 1, __fmt, \
                __va_arg_pack ());

......
In function ‘fprintf’,
  inlined from ‘perf_sample__fprintf_regs.isra’ at \
    builtin-script.c:622:14:
/usr/include/aarch64-linux-gnu/bits/stdio2.h:100:10: \
    error: ‘%5s’ directive argument is null [-Werror=format-overflow=]
  100 |   return __fprintf_chk (__stream, __USE_FORTIFY_LEVEL - 1, __fmt,
  101 |                         __va_arg_pack ());

cc1: all warnings being treated as errors
.......

This patch fixes Wformat-overflow warnings. Add helper function to
convert NULL to "unknown".

Signed-off-by: Jianlin Lv <Jianlin.Lv at arm.com>
---
v2: Add ternary operator to avoid similar errors in other arch.
v3: Declared reg_name in inner block.
v4: Add helper function: perf_reg_name_str, update changelog.
v5: Correct function names to follow common naming conventions.
---
 tools/perf/arch/arm/include/perf_regs.h     | 2 +-
 tools/perf/arch/arm64/include/perf_regs.h   | 2 +-
 tools/perf/arch/csky/include/perf_regs.h    | 2 +-
 tools/perf/arch/powerpc/include/perf_regs.h | 2 +-
 tools/perf/arch/riscv/include/perf_regs.h   | 2 +-
 tools/perf/arch/s390/include/perf_regs.h    | 2 +-
 tools/perf/arch/x86/include/perf_regs.h     | 2 +-
 tools/perf/util/perf_regs.h                 | 7 +++++++
 8 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/tools/perf/arch/arm/include/perf_regs.h b/tools/perf/arch/arm/include/perf_regs.h
index ed20e0253e25..4085419283d0 100644
--- a/tools/perf/arch/arm/include/perf_regs.h
+++ b/tools/perf/arch/arm/include/perf_regs.h
@@ -15,7 +15,7 @@ void perf_regs_load(u64 *regs);
 #define PERF_REG_IP	PERF_REG_ARM_PC
 #define PERF_REG_SP	PERF_REG_ARM_SP
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_ARM_R0:
diff --git a/tools/perf/arch/arm64/include/perf_regs.h b/tools/perf/arch/arm64/include/perf_regs.h
index baaa5e64a3fb..fa3e07459f76 100644
--- a/tools/perf/arch/arm64/include/perf_regs.h
+++ b/tools/perf/arch/arm64/include/perf_regs.h
@@ -15,7 +15,7 @@ void perf_regs_load(u64 *regs);
 #define PERF_REG_IP	PERF_REG_ARM64_PC
 #define PERF_REG_SP	PERF_REG_ARM64_SP
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_ARM64_X0:
diff --git a/tools/perf/arch/csky/include/perf_regs.h b/tools/perf/arch/csky/include/perf_regs.h
index 8f336ea1161a..25ac3bdcb9d1 100644
--- a/tools/perf/arch/csky/include/perf_regs.h
+++ b/tools/perf/arch/csky/include/perf_regs.h
@@ -15,7 +15,7 @@
 #define PERF_REG_IP	PERF_REG_CSKY_PC
 #define PERF_REG_SP	PERF_REG_CSKY_SP
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_CSKY_A0:
diff --git a/tools/perf/arch/powerpc/include/perf_regs.h b/tools/perf/arch/powerpc/include/perf_regs.h
index 63f3ac91049f..004bed228693 100644
--- a/tools/perf/arch/powerpc/include/perf_regs.h
+++ b/tools/perf/arch/powerpc/include/perf_regs.h
@@ -73,7 +73,7 @@ static const char *reg_names[] = {
 	[PERF_REG_POWERPC_SIER3] = "sier3",
 };
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	return reg_names[id];
 }
diff --git a/tools/perf/arch/riscv/include/perf_regs.h b/tools/perf/arch/riscv/include/perf_regs.h
index 7a8bcde7a2b1..6b02a767c918 100644
--- a/tools/perf/arch/riscv/include/perf_regs.h
+++ b/tools/perf/arch/riscv/include/perf_regs.h
@@ -19,7 +19,7 @@
 #define PERF_REG_IP	PERF_REG_RISCV_PC
 #define PERF_REG_SP	PERF_REG_RISCV_SP
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_RISCV_PC:
diff --git a/tools/perf/arch/s390/include/perf_regs.h b/tools/perf/arch/s390/include/perf_regs.h
index bcfbaed78cc2..ce3031526623 100644
--- a/tools/perf/arch/s390/include/perf_regs.h
+++ b/tools/perf/arch/s390/include/perf_regs.h
@@ -14,7 +14,7 @@ void perf_regs_load(u64 *regs);
 #define PERF_REG_IP PERF_REG_S390_PC
 #define PERF_REG_SP PERF_REG_S390_R15
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_S390_R0:
diff --git a/tools/perf/arch/x86/include/perf_regs.h b/tools/perf/arch/x86/include/perf_regs.h
index b7321337d100..cddc4cdc0d9b 100644
--- a/tools/perf/arch/x86/include/perf_regs.h
+++ b/tools/perf/arch/x86/include/perf_regs.h
@@ -23,7 +23,7 @@ void perf_regs_load(u64 *regs);
 #define PERF_REG_IP PERF_REG_X86_IP
 #define PERF_REG_SP PERF_REG_X86_SP
 
-static inline const char *perf_reg_name(int id)
+static inline const char *__perf_reg_name(int id)
 {
 	switch (id) {
 	case PERF_REG_X86_AX:
diff --git a/tools/perf/util/perf_regs.h b/tools/perf/util/perf_regs.h
index a45499126184..eeac181ebccf 100644
--- a/tools/perf/util/perf_regs.h
+++ b/tools/perf/util/perf_regs.h
@@ -33,6 +33,13 @@ extern const struct sample_reg sample_reg_masks[];
 
 int perf_reg_value(u64 *valp, struct regs_dump *regs, int id);
 
+static inline const char *perf_reg_name(int id)
+{
+	const char *reg_name = __perf_reg_name(id);
+
+	return reg_name ?: "unknown";
+}
+
 #else
 #define PERF_REGS_MASK	0
 #define PERF_REGS_MAX	0
-- 
2.25.1