[PATCH v3 1/3] Use enum for return method for dummy calls

Alan Hayward
2018-10-11T14:49:20Z

In call_function_by_hand_dummy, struct_return and hidden_first_param_p
are used to represent a single concept. Replace with an enum.

gdb/ChangeLog:

2018-10-11 Alan Hayward <alan.hayward@arm.com>

* gdbarch.sh (enum function_call_return_method): Add enum.
* gdbarch.h: Regenerate.
* infcall.c (call_function_by_hand_dummy): Replace vars with enum.
---
gdb/gdbarch.h | 17 +++++++++++++++++
gdb/gdbarch.sh | 17 +++++++++++++++++
gdb/infcall.c | 29 +++++++++++------------------
3 files changed, 45 insertions(+), 18 deletions(-)

diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index fc2f1a84a1..5f9cf481fb 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -102,6 +102,23 @@ typedef void (iterate_over_regset_sections_cb)
(const char *sect_name, int supply_size, int collect_size,
const struct regset *regset, const char *human_name, void *cb_data);

+/* For a function call, are we returning a value using a normal value return
+ or a structure return - passing a hidden argument pointing to storage.
+ There are two cases: language-mandated structure return and target ABI
+ structure return. The language version is handled by passing the return
+ location as the first parameter to the function, even preceding "this".
+ This is different from the target ABI version, which is target-specific; for
+ instance, on ia64 the first argument is passed in out0 but the hidden
+ structure return pointer would normally be passed in r8. */
+
+enum function_call_return_method
+{
+ return_method_normal = 0, /* Standard value return. */
+ return_method_struct, /* target ABI structure return. */
+ return_method_hidden_param /* Return hidden in first param. */
+};
+
+

/* The following are pre-initialized by GDBARCH. */

diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 670ac30c03..940f10e4d3 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1327,6 +1327,23 @@ typedef int (iterate_over_objfiles_in_search_order_cb_ftype)
typedef void (iterate_over_regset_sections_cb)
(const char *sect_name, int supply_size, int collect_size,
const struct regset *regset, const char *human_name, void *cb_data);
+
+/* For a function call, are we returning a value using a normal value return
+ or a structure return - passing a hidden argument pointing to storage.
+ There are two cases: language-mandated structure return and target ABI
+ structure return. The language version is handled by passing the return
+ location as the first parameter to the function, even preceding "this".
+ This is different from the target ABI version, which is target-specific; for
+ instance, on ia64 the first argument is passed in out0 but the hidden
+ structure return pointer would normally be passed in r8. */
+
+enum function_call_return_method
+{
+ return_method_normal = 0, /* Standard value return. */
+ return_method_struct, /* target ABI structure return. */
+ return_method_hidden_param /* Return hidden in first param. */
+};
+
EOF

# function typedef's
diff --git a/gdb/infcall.c b/gdb/infcall.c
index 96d43704fa..0c875ea4b9 100644
--- a/gdb/infcall.c
+++ b/gdb/infcall.c
@@ -719,7 +719,7 @@ call_function_by_hand_dummy (struct value *function,
{
CORE_ADDR sp;
struct type *target_values_type;
- unsigned char struct_return = 0, hidden_first_param_p = 0;
+ function_call_return_method return_method = return_method_normal;
CORE_ADDR struct_addr = 0;
CORE_ADDR real_pc;
CORE_ADDR bp_addr;
@@ -876,20 +876,11 @@ call_function_by_hand_dummy (struct value *function,

values_type = check_typedef (values_type);

- /* Are we returning a value using a structure return (passing a
- hidden argument pointing to storage) or a normal value return?
- There are two cases: language-mandated structure return and
- target ABI structure return. The variable STRUCT_RETURN only
- describes the latter. The language version is handled by passing
- the return location as the first parameter to the function,
- even preceding "this". This is different from the target
- ABI version, which is target-specific; for instance, on ia64
- the first argument is passed in out0 but the hidden structure
- return pointer would normally be passed in r8. */
+ /* Are we returning a value using a structure return? */

if (gdbarch_return_in_first_hidden_param_p (gdbarch, values_type))
{
- hidden_first_param_p = 1;
+ return_method = return_method_hidden_param;

/* Tell the target specific argument pushing routine not to
expect a value. */
@@ -897,7 +888,8 @@ call_function_by_hand_dummy (struct value *function,
}
else
{
- struct_return = using_struct_return (gdbarch, function, values_type);
+ if (using_struct_return (gdbarch, function, values_type))
+ return_method = return_method_struct;
target_values_type = values_type;
}

@@ -1020,7 +1012,7 @@ call_function_by_hand_dummy (struct value *function,
is being evaluated is OK because the thread is stopped until the
expression is completely evaluated. */

- if (struct_return || hidden_first_param_p
+ if (return_method != return_method_normal
|| (stack_temporaries && class_or_union_p (values_type)))
{
if (gdbarch_inner_than (gdbarch, 1, 2))
@@ -1046,7 +1038,7 @@ call_function_by_hand_dummy (struct value *function,
}

std::vector<struct value *> new_args;
- if (hidden_first_param_p)
+ if (return_method == return_method_hidden_param)
{
/* Add the new argument to the front of the argument list. */
new_args.push_back
@@ -1060,8 +1052,9 @@ call_function_by_hand_dummy (struct value *function,
presumably, the ABI code knows where, in the call dummy, the
return address should be pointed. */
sp = gdbarch_push_dummy_call (gdbarch, function, get_current_regcache (),
- bp_addr, nargs, args,
- sp, struct_return, struct_addr);
+ bp_addr, nargs, args, sp,
+ (return_method == return_method_struct),
+ struct_addr);

/* Set up a frame ID for the dummy frame so we can pass it to
set_momentary_breakpoint. We need to give the breakpoint a frame
@@ -1157,7 +1150,7 @@ call_function_by_hand_dummy (struct value *function,
sm = new_call_thread_fsm (current_ui, command_interp (),
gdbarch, function,
values_type,
- struct_return || hidden_first_param_p,
+ return_method != return_method_normal,
struct_addr);

e = run_inferior_call (sm, call_thread.get (), real_pc);
--
2.17.1 (Apple Git-112)