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Re: [PATCH 6/6] [ARC] Add 'aux' variable attribute.
- From: Andrew Burgess <andrew dot burgess at embecosm dot com>
- To: Claudiu Zissulescu <Claudiu dot Zissulescu at synopsys dot com>
- Cc: gcc-patches at gcc dot gnu dot org, Francois dot Bedard at synopsys dot com
- Date: Mon, 29 Jan 2018 19:26:18 +0000
- Subject: Re: [PATCH 6/6] [ARC] Add 'aux' variable attribute.
- Authentication-results: sourceware.org; auth=none
- References: <1509625835-22344-1-git-send-email-claziss@synopsys.com> <1509625835-22344-7-git-send-email-claziss@synopsys.com>
* Claudiu Zissulescu <Claudiu.Zissulescu@synopsys.com> [2017-11-02 13:30:35 +0100]:
> From: claziss <claziss@synopsys.com>
>
> The 'aux' variable attribute is used to directly access the auxiliary
> register space from C.
>
> gcc/
> 2017-07-25 Claudiu Zissulescu <claziss@synopsys.com>
>
> * config/arc/arc.c (arc_handle_aux_attribute): New function.
> (arc_attribute_table): Add 'aux' attribute.
> (arc_in_small_data_p): Consider aux like variables.
> (arc_is_aux_reg_p): New function.
> (arc_asm_output_aligned_decl_local): Ignore 'aux' like variables.
> (arc_get_aux_arg): New function.
> (prepare_move_operands): Handle aux-register access.
> (arc_handle_aux_attribute): New function.
> * doc/extend.texi (ARC Variable attributes): Add subsection.
>
> testsuite/
> 2017-07-25 Claudiu Zissulescu <claziss@synopsys.com>
>
> * gcc.target/arc/taux-1.c: New test.
> * gcc.target/arc/taux-2.c: Likewise.
Looks good.
Sorry for the time taken to review this series.
Thanks,
Andrew
> ---
> gcc/config/arc/arc.c | 160 +++++++++++++++++++++++++++++++++-
> gcc/doc/extend.texi | 13 +++
> gcc/testsuite/gcc.target/arc/taux-1.c | 38 ++++++++
> gcc/testsuite/gcc.target/arc/taux-2.c | 15 ++++
> 4 files changed, 225 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.target/arc/taux-1.c
> create mode 100644 gcc/testsuite/gcc.target/arc/taux-2.c
>
> diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
> index a397cbd..33f68ef 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -223,6 +223,7 @@ static tree arc_handle_fndecl_attribute (tree *, tree, tree, int, bool *);
> static tree arc_handle_jli_attribute (tree *, tree, tree, int, bool *);
> static tree arc_handle_secure_attribute (tree *, tree, tree, int, bool *);
> static tree arc_handle_uncached_attribute (tree *, tree, tree, int, bool *);
> +static tree arc_handle_aux_attribute (tree *, tree, tree, int, bool *);
>
> /* Initialized arc_attribute_table to NULL since arc doesnot have any
> machine specific supported attributes. */
> @@ -257,6 +258,8 @@ const struct attribute_spec arc_attribute_table[] =
> /* Bypass caches using .di flag. */
> { "uncached", 0, 0, false, true, false, arc_handle_uncached_attribute,
> false },
> + /* Declare a variable as aux. */
> + { "aux", 0, 1, true, false, false, arc_handle_aux_attribute, false },
> { NULL, 0, 0, false, false, false, NULL, false }
> };
> static int arc_comp_type_attributes (const_tree, const_tree);
> @@ -8071,6 +8074,11 @@ arc_in_small_data_p (const_tree decl)
> if (lookup_attribute ("uncached", attr))
> return false;
>
> + /* and for aux regs. */
> + attr = DECL_ATTRIBUTES (decl);
> + if (lookup_attribute ("aux", attr))
> + return false;
> +
> if (DECL_SECTION_NAME (decl) != 0)
> {
> const char *name = DECL_SECTION_NAME (decl);
> @@ -8238,6 +8246,35 @@ compact_sda_memory_operand (rtx op, machine_mode mode, bool short_p)
> return false;
> }
>
> +/* Return TRUE if PAT is accessing an aux-reg. */
> +
> +static bool
> +arc_is_aux_reg_p (rtx pat)
> +{
> + tree attrs = NULL_TREE;
> + tree addr;
> +
> + if (!MEM_P (pat))
> + return false;
> +
> + /* Get the memory attributes. */
> + addr = MEM_EXPR (pat);
> + if (!addr)
> + return false;
> +
> + /* Get the attributes. */
> + if (TREE_CODE (addr) == VAR_DECL)
> + attrs = DECL_ATTRIBUTES (addr);
> + else if (TREE_CODE (addr) == MEM_REF)
> + attrs = TYPE_ATTRIBUTES (TREE_TYPE (TREE_OPERAND (addr, 0)));
> + else
> + return false;
> +
> + if (lookup_attribute ("aux", attrs))
> + return true;
> + return false;
> +}
> +
> /* Implement ASM_OUTPUT_ALIGNED_DECL_LOCAL. */
>
> void
> @@ -8246,7 +8283,14 @@ arc_asm_output_aligned_decl_local (FILE * stream, tree decl, const char * name,
> unsigned HOST_WIDE_INT align,
> unsigned HOST_WIDE_INT globalize_p)
> {
> - int in_small_data = arc_in_small_data_p (decl);
> + int in_small_data = arc_in_small_data_p (decl);
> + rtx mem = decl == NULL_TREE ? NULL_RTX : DECL_RTL (decl);
> +
> + /* Don't output aux-reg symbols. */
> + if (mem != NULL_RTX && MEM_P (mem)
> + && SYMBOL_REF_P (XEXP (mem, 0))
> + && arc_is_aux_reg_p (mem))
> + return;
>
> if (in_small_data)
> switch_to_section (get_named_section (NULL, ".sbss", 0));
> @@ -8586,12 +8630,80 @@ arc_expand_movmem (rtx *operands)
> return true;
> }
>
> +static bool
> +arc_get_aux_arg (rtx pat, int *auxr)
> +{
> + tree attr, addr = MEM_EXPR (pat);
> + if (TREE_CODE (addr) != VAR_DECL)
> + return false;
> +
> + attr = DECL_ATTRIBUTES (addr);
> + if (lookup_attribute ("aux", attr))
> + {
> + tree arg = TREE_VALUE (attr);
> + if (arg)
> + {
> + *auxr = TREE_INT_CST_LOW (TREE_VALUE (arg));
> + return true;
> + }
> + }
> +
> + return false;
> +}
> +
> /* Prepare operands for move in MODE. Return true iff the move has
> been emitted. */
>
> bool
> prepare_move_operands (rtx *operands, machine_mode mode)
> {
> + /* First handle aux attribute. */
> + if (mode == SImode
> + && (MEM_P (operands[0]) || MEM_P (operands[1])))
> + {
> + rtx tmp;
> + int auxr = 0;
> + if (MEM_P (operands[0]) && arc_is_aux_reg_p (operands[0]))
> + {
> + /* Save operation. */
> + if (arc_get_aux_arg (operands[0], &auxr))
> + {
> + tmp = gen_reg_rtx (SImode);
> + emit_move_insn (tmp, GEN_INT (auxr));
> + }
> + else
> + {
> + tmp = XEXP (operands[0], 0);
> + }
> +
> + operands[1] = force_reg (SImode, operands[1]);
> + emit_insn (gen_rtx_UNSPEC_VOLATILE
> + (VOIDmode, gen_rtvec (2, operands[1], tmp),
> + VUNSPEC_ARC_SR));
> + return true;
> + }
> + if (MEM_P (operands[1]) && arc_is_aux_reg_p (operands[1]))
> + {
> + if (arc_get_aux_arg (operands[1], &auxr))
> + {
> + tmp = gen_reg_rtx (SImode);
> + emit_move_insn (tmp, GEN_INT (auxr));
> + }
> + else
> + {
> + tmp = XEXP (operands[1], 0);
> + gcc_assert (GET_CODE (tmp) == SYMBOL_REF);
> + }
> + /* Load operation. */
> + gcc_assert (REG_P (operands[0]));
> + emit_insn (gen_rtx_SET (operands[0],
> + gen_rtx_UNSPEC_VOLATILE
> + (SImode, gen_rtvec (1, tmp),
> + VUNSPEC_ARC_LR)));
> + return true;
> + }
> + }
> +
> /* We used to do this only for MODE_INT Modes, but addresses to floating
> point variables may well be in the small data section. */
> if (!TARGET_NO_SDATA_SET && small_data_pattern (operands[0], Pmode))
> @@ -11127,6 +11239,52 @@ arc_is_uncached_mem_p (rtx pat)
> return false;
> }
>
> +/* Handle aux attribute. The auxiliary registers are addressed using
> + special instructions lr and sr. The attribute 'aux' indicates if a
> + variable refers to the aux-regs and what is the register number
> + desired. */
> +
> +static tree
> +arc_handle_aux_attribute (tree *node,
> + tree name, tree args, int,
> + bool *no_add_attrs)
> +{
> + /* Isn't it better to use address spaces for the aux-regs? */
> + if (DECL_P (*node))
> + {
> + if (TREE_CODE (*node) != VAR_DECL)
> + {
> + error ("%qE attribute only applies to variables", name);
> + *no_add_attrs = true;
> + }
> + else if (args)
> + {
> + if (TREE_CODE (TREE_VALUE (args)) == NON_LVALUE_EXPR)
> + TREE_VALUE (args) = TREE_OPERAND (TREE_VALUE (args), 0);
> + tree arg = TREE_VALUE (args);
> + if (TREE_CODE (arg) != INTEGER_CST)
> + {
> + warning (0, "%qE attribute allows only an integer "
> + "constant argument", name);
> + *no_add_attrs = true;
> + }
> + /* FIXME! add range check. TREE_INT_CST_LOW (arg) */
> + }
> +
> + if (TREE_CODE (*node) == VAR_DECL)
> + {
> + tree fntype = TREE_TYPE (*node);
> + if (fntype && TREE_CODE (fntype) == POINTER_TYPE)
> + {
> + tree attrs = tree_cons (get_identifier ("aux"), NULL_TREE,
> + TYPE_ATTRIBUTES (fntype));
> + TYPE_ATTRIBUTES (fntype) = attrs;
> + }
> + }
> + }
> + return NULL_TREE;
> +}
> +
> /* Implement TARGET_USE_ANCHORS_FOR_SYMBOL_P. We don't want to use
> anchors for small data: the GP register acts as an anchor in that
> case. We also don't want to use them for PC-relative accesses,
> diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
> index 0f8ba05..1f6ef4e 100644
> --- a/gcc/doc/extend.texi
> +++ b/gcc/doc/extend.texi
> @@ -5803,6 +5803,7 @@ attributes.
>
> @menu
> * Common Variable Attributes::
> +* ARC Variable Attributes::
> * AVR Variable Attributes::
> * Blackfin Variable Attributes::
> * H8/300 Variable Attributes::
> @@ -6165,6 +6166,18 @@ The @code{weak} attribute is described in
>
> @end table
>
> +@node ARC Variable Attributes
> +@subsection ARC Variable Attributes
> +
> +@table @code
> +@item aux
> +@cindex @code{aux} variable attribute, ARC
> +The @code{aux} attribute is used to directly access the ARC's
> +auxiliary register space from C. The auxilirary register number is
> +given via attribute argument.
> +
> +@end table
> +
> @node AVR Variable Attributes
> @subsection AVR Variable Attributes
>
> diff --git a/gcc/testsuite/gcc.target/arc/taux-1.c b/gcc/testsuite/gcc.target/arc/taux-1.c
> new file mode 100644
> index 0000000..a2b7778
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arc/taux-1.c
> @@ -0,0 +1,38 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 */
> +
> +
> +#define __aux() __attribute__((aux))
> +
> +__aux() int *a_ptr;
> +extern __aux() int a_var;
> +
> +/* Generates:
> + mov r0, @a_var
> + sr 10,[r0]
> +*/
> +void foo (void)
> +{
> + a_var = 10;
> +}
> +
> +/* Generates:
> + mov r0, @a_ptr
> + sr a_var,[r0]
> +*/
> +void foo1 (void)
> +{
> + a_ptr = &a_var;
> +}
> +
> +/* Generates:
> + lr %r1,[a_ptr]
> + sr 10,[%r1]
> +*/
> +void foo2 (void)
> +{
> + *a_ptr = 10;
> +}
> +
> +/* { dg-final { scan-assembler-times "sr" 3 } } */
> +/* { dg-final { scan-assembler-times "lr" 1 } } */
> diff --git a/gcc/testsuite/gcc.target/arc/taux-2.c b/gcc/testsuite/gcc.target/arc/taux-2.c
> new file mode 100644
> index 0000000..5644bcd
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/arc/taux-2.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 */
> +
> +#define __aux(r) __attribute__((aux(r)))
> +static volatile __aux(0x1000) int var;
> +
> +int foo (void)
> +{
> + var++;
> +}
> +
> +/* { dg-final { scan-assembler-times "sr" 1 } } */
> +/* { dg-final { scan-assembler-times "lr" 1 } } */
> +/* { dg-final { scan-assembler "4096" } } */
> +/* { dg-final { scan-assembler-not "\\.type\tvar, @object" } } */
> --
> 1.9.1
>