Use it to avoid some clang-12 -Watomic-alignment errors,
forcing some structures to be aligned and as a pointer when
we have ensured that the address is aligned.
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
accel/tcg/atomic_template.h | 4 ++--
include/qemu/atomic.h | 14 +++++++++++++-
include/qemu/stats64.h | 2 +-
softmmu/timers-state.h | 2 +-
linux-user/hppa/cpu_loop.c | 2 +-
util/qsp.c | 4 ++--
6 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/accel/tcg/atomic_template.h b/accel/tcg/atomic_template.h
index afa8a9daf3..d347462af5 100644
--- a/accel/tcg/atomic_template.h
+++ b/accel/tcg/atomic_template.h
@@ -28,8 +28,8 @@
# define SHIFT 4
#elif DATA_SIZE == 8
# define SUFFIX q
-# define DATA_TYPE uint64_t
-# define SDATA_TYPE int64_t
+# define DATA_TYPE aligned_uint64_t
+# define SDATA_TYPE aligned_int64_t
# define BSWAP bswap64
# define SHIFT 3
#elif DATA_SIZE == 4
diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
index bf89855209..f8f159052f 100644
--- a/include/qemu/atomic.h
+++ b/include/qemu/atomic.h
@@ -271,7 +271,19 @@
_oldn; \
})
-/* Abstractions to access atomically (i.e. "once") i64/u64 variables */
+/*
+ * Abstractions to access atomically (i.e. "once") i64/u64 variables.
+ *
+ * The i386 abi is odd in that by default members are only aligned to
+ * 4 bytes, which means that 8-byte types can wind up mis-aligned.
+ * Clang will then warn about this, and emit a call into libatomic.
+ *
+ * Use of these types in structures when they will be used with atomic
+ * operations can avoid this.
+ */
+typedef int64_t aligned_int64_t __attribute__((aligned(8)));
+typedef uint64_t aligned_uint64_t __attribute__((aligned(8)));
+
#ifdef CONFIG_ATOMIC64
/* Use __nocheck because sizeof(void *) might be < sizeof(u64) */
#define qatomic_read_i64 qatomic_read__nocheck
diff --git a/include/qemu/stats64.h b/include/qemu/stats64.h
index fdd3d1b8f9..802402254b 100644
--- a/include/qemu/stats64.h
+++ b/include/qemu/stats64.h
@@ -21,7 +21,7 @@
typedef struct Stat64 {
#ifdef CONFIG_ATOMIC64
- uint64_t value;
+ aligned_uint64_t value;
#else
uint32_t low, high;
uint32_t lock;
diff --git a/softmmu/timers-state.h b/softmmu/timers-state.h
index 8c262ce139..94bb7394c5 100644
--- a/softmmu/timers-state.h
+++ b/softmmu/timers-state.h
@@ -47,7 +47,7 @@ typedef struct TimersState {
int64_t last_delta;
/* Compensate for varying guest execution speed. */
- int64_t qemu_icount_bias;
+ aligned_int64_t qemu_icount_bias;
int64_t vm_clock_warp_start;
int64_t cpu_clock_offset;
diff --git a/linux-user/hppa/cpu_loop.c b/linux-user/hppa/cpu_loop.c
index 3aaaf3337c..82d8183821 100644
--- a/linux-user/hppa/cpu_loop.c
+++ b/linux-user/hppa/cpu_loop.c
@@ -82,7 +82,7 @@ static abi_ulong hppa_lws(CPUHPPAState *env)
o64 = *(uint64_t *)g2h(cs, old);
n64 = *(uint64_t *)g2h(cs, new);
#ifdef CONFIG_ATOMIC64
- r64 = qatomic_cmpxchg__nocheck((uint64_t *)g2h(cs, addr),
+ r64 = qatomic_cmpxchg__nocheck((aligned_uint64_t *)g2h(cs, addr),
o64, n64);
ret = r64 != o64;
#else
diff --git a/util/qsp.c b/util/qsp.c
index bacc5fa2f6..8562b14a87 100644
--- a/util/qsp.c
+++ b/util/qsp.c
@@ -83,8 +83,8 @@ typedef struct QSPCallSite QSPCallSite;
struct QSPEntry {
void *thread_ptr;
const QSPCallSite *callsite;
- uint64_t n_acqs;
- uint64_t ns;
+ aligned_uint64_t n_acqs;
+ aligned_uint64_t ns;
unsigned int n_objs; /* count of coalesced objs; only used for reporting */
};
typedef struct QSPEntry QSPEntry;
--
2.25.1