310 lines
9.4 KiB
Diff
310 lines
9.4 KiB
Diff
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commit cc0e89c519912e0e4e75a2fc0d836f715cdc6806
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Author: Ulrich Weigand <ulrich.weigand@de.ibm.com>
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Date: Tue Feb 4 18:42:35 2014 +0100
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PowerPC64 ELFv2 ABI: structure passing / return
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Another significant difference in the ELFv2 ABI is that "homogeneous"
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floating-point and vector aggregates, i.e. aggregates the consist
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(recursively) only of members of the same floating-point or vector type,
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are passed in a series of floating-point / vector registers, as if they
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were seperate parameters. (This is similar to the ARM ABI.) This
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applies to both calls and returns.
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In addition when returning any aggregate of up to 16 bytes, ELFv2 now
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used general-purpose registers.
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This patch adds support for these aspects of the ABI, which is relatively
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straightforward after the refactoring patch to ppc-sysv-tdep.c.
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gdb/ChangeLog:
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* ppc-sysv-tdep.c (ppc64_aggregate_candidate): New routine.
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(ppc64_elfv2_abi_homogeneous_aggregate): Likewise.
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(ppc64_sysv_abi_push_param): Handle ELFv2 homogeneous structs.
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(ppc64_sysv_abi_return_value): Likewise. Also, handle small
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structures returned in GPRs.
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### a/gdb/ChangeLog
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### b/gdb/ChangeLog
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## -1,5 +1,13 @@
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2014-02-04 Ulrich Weigand <uweigand@de.ibm.com>
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+ * ppc-sysv-tdep.c (ppc64_aggregate_candidate): New routine.
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+ (ppc64_elfv2_abi_homogeneous_aggregate): Likewise.
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+ (ppc64_sysv_abi_push_param): Handle ELFv2 homogeneous structs.
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+ (ppc64_sysv_abi_return_value): Likewise. Also, handle small
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+ structures returned in GPRs.
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+
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+2014-02-04 Ulrich Weigand <uweigand@de.ibm.com>
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+
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* ppc-sysv-tdep.c (ppc64_sysv_abi_push_dummy_call): Use correct
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offset to the stack parameter list for the ELFv2 ABI.
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--- a/gdb/ppc-sysv-tdep.c
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+++ b/gdb/ppc-sysv-tdep.c
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@@ -1101,6 +1101,160 @@ convert_code_addr_to_desc_addr (CORE_ADDR code_addr, CORE_ADDR *desc_addr)
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return 1;
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}
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+/* Walk down the type tree of TYPE counting consecutive base elements.
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+ If *FIELD_TYPE is NULL, then set it to the first valid floating point
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+ or vector type. If a non-floating point or vector type is found, or
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+ if a floating point or vector type that doesn't match a non-NULL
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+ *FIELD_TYPE is found, then return -1, otherwise return the count in the
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+ sub-tree. */
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+
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+static LONGEST
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+ppc64_aggregate_candidate (struct type *type,
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+ struct type **field_type)
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+{
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+ type = check_typedef (type);
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+
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+ switch (TYPE_CODE (type))
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+ {
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+ case TYPE_CODE_FLT:
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+ case TYPE_CODE_DECFLOAT:
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+ if (!*field_type)
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+ *field_type = type;
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+ if (TYPE_CODE (*field_type) == TYPE_CODE (type)
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+ && TYPE_LENGTH (*field_type) == TYPE_LENGTH (type))
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+ return 1;
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+ break;
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+
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+ case TYPE_CODE_COMPLEX:
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+ type = TYPE_TARGET_TYPE (type);
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+ if (TYPE_CODE (type) == TYPE_CODE_FLT
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+ || TYPE_CODE (type) == TYPE_CODE_DECFLOAT)
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+ {
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+ if (!*field_type)
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+ *field_type = type;
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+ if (TYPE_CODE (*field_type) == TYPE_CODE (type)
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+ && TYPE_LENGTH (*field_type) == TYPE_LENGTH (type))
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+ return 2;
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+ }
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+ break;
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+
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+ case TYPE_CODE_ARRAY:
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+ if (TYPE_VECTOR (type))
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+ {
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+ if (!*field_type)
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+ *field_type = type;
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+ if (TYPE_CODE (*field_type) == TYPE_CODE (type)
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+ && TYPE_LENGTH (*field_type) == TYPE_LENGTH (type))
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+ return 1;
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+ }
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+ else
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+ {
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+ LONGEST count, low_bound, high_bound;
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+
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+ count = ppc64_aggregate_candidate
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+ (TYPE_TARGET_TYPE (type), field_type);
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+ if (count == -1)
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+ return -1;
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+
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+ if (!get_array_bounds (type, &low_bound, &high_bound))
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+ return -1;
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+ count *= high_bound - low_bound;
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+
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+ /* There must be no padding. */
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+ if (count == 0)
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+ return TYPE_LENGTH (type) == 0 ? 0 : -1;
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+ else if (TYPE_LENGTH (type) != count * TYPE_LENGTH (*field_type))
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+ return -1;
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+
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+ return count;
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+ }
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+ break;
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+
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+ case TYPE_CODE_STRUCT:
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+ case TYPE_CODE_UNION:
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+ {
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+ LONGEST count = 0;
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+ int i;
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+
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+ for (i = 0; i < TYPE_NFIELDS (type); i++)
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+ {
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+ LONGEST sub_count;
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+
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+ if (field_is_static (&TYPE_FIELD (type, i)))
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+ continue;
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+
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+ sub_count = ppc64_aggregate_candidate
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+ (TYPE_FIELD_TYPE (type, i), field_type);
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+ if (sub_count == -1)
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+ return -1;
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+
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+ if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
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+ count += sub_count;
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+ else
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+ count = max (count, sub_count);
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+ }
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+
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+ /* There must be no padding. */
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+ if (count == 0)
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+ return TYPE_LENGTH (type) == 0 ? 0 : -1;
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+ else if (TYPE_LENGTH (type) != count * TYPE_LENGTH (*field_type))
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+ return -1;
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+
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+ return count;
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+ }
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+ break;
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+
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+ default:
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+ break;
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+ }
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+
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+ return -1;
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+}
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+
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+/* If an argument of type TYPE is a homogeneous float or vector aggregate
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+ that shall be passed in FP/vector registers according to the ELFv2 ABI,
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+ return the homogeneous element type in *ELT_TYPE and the number of
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+ elements in *N_ELTS, and return non-zero. Otherwise, return zero. */
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+
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+static int
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+ppc64_elfv2_abi_homogeneous_aggregate (struct type *type,
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+ struct type **elt_type, int *n_elts)
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+{
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+ /* Complex types at the top level are treated separately. However,
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+ complex types can be elements of homogeneous aggregates. */
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+ if (TYPE_CODE (type) == TYPE_CODE_STRUCT
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+ || TYPE_CODE (type) == TYPE_CODE_UNION
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+ || (TYPE_CODE (type) == TYPE_CODE_ARRAY && !TYPE_VECTOR (type)))
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+ {
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+ struct type *field_type = NULL;
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+ LONGEST field_count = ppc64_aggregate_candidate (type, &field_type);
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+
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+ if (field_count > 0)
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+ {
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+ int n_regs = ((TYPE_CODE (field_type) == TYPE_CODE_FLT
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+ || TYPE_CODE (field_type) == TYPE_CODE_DECFLOAT)?
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+ (TYPE_LENGTH (field_type) + 7) >> 3 : 1);
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+
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+ /* The ELFv2 ABI allows homogeneous aggregates to occupy
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+ up to 8 registers. */
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+ if (field_count * n_regs <= 8)
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+ {
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+ if (elt_type)
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+ *elt_type = field_type;
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+ if (n_elts)
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+ *n_elts = (int) field_count;
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+ /* Note that field_count is LONGEST since it may hold the size
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+ of an array, while *n_elts is int since its value is bounded
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+ by the number of registers used for argument passing. The
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+ cast cannot overflow due to the bounds checking above. */
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+ return 1;
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+ }
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+ }
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+ }
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+
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+ return 0;
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+}
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+
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/* Structure holding the next argument position. */
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struct ppc64_sysv_argpos
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{
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@@ -1389,6 +1543,29 @@ ppc64_sysv_abi_push_param (struct gdbarch *gdbarch,
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if (TYPE_CODE (type) == TYPE_CODE_FLT)
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ppc64_sysv_abi_push_freg (gdbarch, type, val, argpos);
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}
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+
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+ /* In the ELFv2 ABI, homogeneous floating-point or vector
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+ aggregates are passed in a series of registers. */
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+ if (tdep->elf_abi == POWERPC_ELF_V2)
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+ {
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+ struct type *eltype;
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+ int i, nelt;
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+
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+ if (ppc64_elfv2_abi_homogeneous_aggregate (type, &eltype, &nelt))
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+ for (i = 0; i < nelt; i++)
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+ {
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+ const gdb_byte *elval = val + i * TYPE_LENGTH (eltype);
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+
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+ if (TYPE_CODE (eltype) == TYPE_CODE_FLT
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+ || TYPE_CODE (eltype) == TYPE_CODE_DECFLOAT)
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+ ppc64_sysv_abi_push_freg (gdbarch, eltype, elval, argpos);
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+ else if (TYPE_CODE (eltype) == TYPE_CODE_ARRAY
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+ && TYPE_VECTOR (eltype)
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+ && tdep->vector_abi == POWERPC_VEC_ALTIVEC
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+ && TYPE_LENGTH (eltype) == 16)
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+ ppc64_sysv_abi_push_vreg (gdbarch, elval, argpos);
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+ }
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+ }
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}
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}
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@@ -1834,6 +2011,72 @@ ppc64_sysv_abi_return_value (struct gdbarch *gdbarch, struct value *function,
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return RETURN_VALUE_REGISTER_CONVENTION;
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}
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+ /* In the ELFv2 ABI, homogeneous floating-point or vector
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+ aggregates are returned in registers. */
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+ if (tdep->elf_abi == POWERPC_ELF_V2
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+ && ppc64_elfv2_abi_homogeneous_aggregate (valtype, &eltype, &nelt))
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+ {
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+ for (i = 0; i < nelt; i++)
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+ {
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+ ok = ppc64_sysv_abi_return_value_base (gdbarch, eltype, regcache,
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+ readbuf, writebuf, i);
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+ gdb_assert (ok);
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+
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+ if (readbuf)
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+ readbuf += TYPE_LENGTH (eltype);
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+ if (writebuf)
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+ writebuf += TYPE_LENGTH (eltype);
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+ }
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+
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+ return RETURN_VALUE_REGISTER_CONVENTION;
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+ }
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+
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+ /* In the ELFv2 ABI, aggregate types of up to 16 bytes are
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+ returned in registers r3:r4. */
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+ if (tdep->elf_abi == POWERPC_ELF_V2
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+ && TYPE_LENGTH (valtype) <= 16
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+ && (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
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+ || TYPE_CODE (valtype) == TYPE_CODE_UNION
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+ || (TYPE_CODE (valtype) == TYPE_CODE_ARRAY
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+ && !TYPE_VECTOR (valtype))))
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+ {
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+ int n_regs = ((TYPE_LENGTH (valtype) + tdep->wordsize - 1)
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+ / tdep->wordsize);
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+ int i;
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+
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+ for (i = 0; i < n_regs; i++)
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+ {
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+ gdb_byte regval[MAX_REGISTER_SIZE];
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+ int regnum = tdep->ppc_gp0_regnum + 3 + i;
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+ int offset = i * tdep->wordsize;
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+ int len = TYPE_LENGTH (valtype) - offset;
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+
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+ if (len > tdep->wordsize)
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+ len = tdep->wordsize;
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+
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+ if (writebuf != NULL)
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+ {
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+ memset (regval, 0, sizeof regval);
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+ if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG
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+ && offset == 0)
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+ memcpy (regval + tdep->wordsize - len, writebuf, len);
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+ else
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+ memcpy (regval, writebuf + offset, len);
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+ regcache_cooked_write (regcache, regnum, regval);
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+ }
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+ if (readbuf != NULL)
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+ {
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+ regcache_cooked_read (regcache, regnum, regval);
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+ if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG
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+ && offset == 0)
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+ memcpy (readbuf, regval + tdep->wordsize - len, len);
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+ else
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+ memcpy (readbuf + offset, regval, len);
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+ }
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+ }
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+ return RETURN_VALUE_REGISTER_CONVENTION;
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+ }
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+
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/* Handle plain base types. */
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if (ppc64_sysv_abi_return_value_base (gdbarch, valtype, regcache,
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readbuf, writebuf, 0))
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