On Fri, Jan 8, 2016 at 4:53 PM, Alex Bennée <alex.ben...@linaro.org> wrote:
> From: Alvise Rigo <a.r...@virtualopensystems.com>
>
> Attempting to simplify the helper_*_st_name, wrap the
> do_unaligned_access code into an shared inline function. As this also
> removes the goto statement the inline code is expanded twice in each
> helper.
>
> Suggested-by: Jani Kokkonen <jani.kokko...@huawei.com>
> Suggested-by: Claudio Fontana <claudio.font...@huawei.com>
> CC: Alvise Rigo <a.r...@virtualopensystems.com>
> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
>
> ---
> v2
> - based on original patch from Alvise
> - uses a single shared inline function to reduce duplication
> ---
> softmmu_template.h | 75
> ++++++++++++++++++++++++++++--------------------------
> 1 file changed, 39 insertions(+), 36 deletions(-)
>
> diff --git a/softmmu_template.h b/softmmu_template.h
> index 0074bd7..ac0b4ac 100644
> --- a/softmmu_template.h
> +++ b/softmmu_template.h
> @@ -159,6 +159,39 @@ static inline int smmu_helper(victim_tlb_hit) (const
> bool is_read, CPUArchState
> }
>
> #ifndef SOFTMMU_CODE_ACCESS
> +
> +static inline void smmu_helper(do_unl_store)(CPUArchState *env,
> + bool little_endian,
> + DATA_TYPE val,
> + target_ulong addr,
> + TCGMemOpIdx oi,
> + unsigned mmu_idx,
> + uintptr_t retaddr)
> +{
> + int i;
> +
> + if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> + cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> + mmu_idx, retaddr);
> + }
> + /* Note: relies on the fact that tlb_fill() does not remove the
> + * previous page from the TLB cache. */
> + for (i = DATA_SIZE - 1; i >= 0; i--) {
> + uint8_t val8;
> + if (little_endian) {
> + /* Little-endian extract. */
> + val8 = val >> (i * 8);
> + } else {
> + /* Big-endian extract. */
> + val8 = val >> (((DATA_SIZE - 1) * 8) - (i * 8));
> + }
> + /* Note the adjustment at the beginning of the function.
> + Undo that for the recursion. */
> + glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> + oi, retaddr + GETPC_ADJ);
> + }
> +}
> +
> static inline DATA_TYPE glue(io_read, SUFFIX)(CPUArchState *env,
> CPUIOTLBEntry *iotlbentry,
> target_ulong addr,
> @@ -416,7 +449,8 @@ void helper_le_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
> CPUIOTLBEntry *iotlbentry;
> if ((addr & (DATA_SIZE - 1)) != 0) {
> - goto do_unaligned_access;
> + smmu_helper(do_unl_store)(env, true, val, addr, oi, mmu_idx,
> retaddr);
> + return;
> }
> iotlbentry = &env->iotlb[mmu_idx][index];
>
> @@ -431,23 +465,7 @@ void helper_le_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (DATA_SIZE > 1
> && unlikely((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1
> >= TARGET_PAGE_SIZE)) {
> - int i;
> - do_unaligned_access:
> - if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> - cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> - mmu_idx, retaddr);
> - }
> - /* XXX: not efficient, but simple */
> - /* Note: relies on the fact that tlb_fill() does not remove the
> - * previous page from the TLB cache. */
> - for (i = DATA_SIZE - 1; i >= 0; i--) {
> - /* Little-endian extract. */
> - uint8_t val8 = val >> (i * 8);
> - /* Note the adjustment at the beginning of the function.
> - Undo that for the recursion. */
> - glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> - oi, retaddr + GETPC_ADJ);
> - }
> + smmu_helper(do_unl_store)(env, true, val, addr, oi, mmu_idx,
> retaddr);
> return;
> }
>
> @@ -496,7 +514,8 @@ void helper_be_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (unlikely(tlb_addr & ~TARGET_PAGE_MASK)) {
> CPUIOTLBEntry *iotlbentry;
> if ((addr & (DATA_SIZE - 1)) != 0) {
> - goto do_unaligned_access;
> + smmu_helper(do_unl_store)(env, false, val, addr, oi, mmu_idx,
> retaddr);
> + return;
> }
> iotlbentry = &env->iotlb[mmu_idx][index];
>
> @@ -511,23 +530,7 @@ void helper_be_st_name(CPUArchState *env, target_ulong
> addr, DATA_TYPE val,
> if (DATA_SIZE > 1
> && unlikely((addr & ~TARGET_PAGE_MASK) + DATA_SIZE - 1
> >= TARGET_PAGE_SIZE)) {
> - int i;
> - do_unaligned_access:
> - if ((get_memop(oi) & MO_AMASK) == MO_ALIGN) {
> - cpu_unaligned_access(ENV_GET_CPU(env), addr, MMU_DATA_STORE,
> - mmu_idx, retaddr);
> - }
> - /* XXX: not efficient, but simple */
> - /* Note: relies on the fact that tlb_fill() does not remove the
> - * previous page from the TLB cache. */
> - for (i = DATA_SIZE - 1; i >= 0; i--) {
> - /* Big-endian extract. */
> - uint8_t val8 = val >> (((DATA_SIZE - 1) * 8) - (i * 8));
> - /* Note the adjustment at the beginning of the function.
> - Undo that for the recursion. */
> - glue(helper_ret_stb, MMUSUFFIX)(env, addr + i, val8,
> - oi, retaddr + GETPC_ADJ);
> - }
> + smmu_helper(do_unl_store)(env, false, val, addr, oi, mmu_idx,
> retaddr);
> return;
> }
>
> --
> 2.6.4
>
This approach makes sense to me, given that the leg of the *if*
statement is actually inlined depending on the (constant) value of
little_endian.
The thing not convincing me is the fact that we are not imposing the
inlining, but we are relying on the compiler optimizations to do it. I
wonder if this will always happen, even with other compilers (clang).
alvise
