[GOLD] PowerPC --stub-group-multi

Adds a new option, defaulting to off, that allows a group of stubs to
serve multiple output sections.  Prior to this patch powerpc gold
allowed this unconditionally, which is a little unsafe with clever
code that discards/reuses sections at runtime.

	* options.h (--stub-group-multi): New PowerPC option.
	* powerpc.cc (Stub_control): Add multi_os_ var and param
	to constructor.  Sort start_ var later.  Comment State.
	(Stub_control::can_add_to_stub_group): Heed multi_os_.
	(Target_powerpc::group_sections): Update.
This commit is contained in:
Alan Modra 2016-12-07 14:15:59 +10:30
parent a5018ae555
commit 1c3a5fbe15
3 changed files with 42 additions and 19 deletions

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@ -1,3 +1,11 @@
2016-12-07 Alan Modra <amodra@gmail.com>
* options.h (--stub-group-multi): New PowerPC option.
* powerpc.cc (Stub_control): Add multi_os_ var and param
to constructor. Sort start_ var later. Comment State.
(Stub_control::can_add_to_stub_group): Heed multi_os_.
(Target_powerpc::group_sections): Update.
2016-12-07 Alan Modra <amodra@gmail.com>
PR gold/20878

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@ -1219,6 +1219,10 @@ class General_options
"stubs are always after the group. 1 means use default size"),
N_("SIZE"));
DEFINE_bool(stub_group_multi, options::TWO_DASHES, '\0', false,
N_("(PowerpC only) Allow a group of stubs to serve multiple "
"output sections"), NULL);
DEFINE_uint(split_stack_adjust_size, options::TWO_DASHES, '\0', 0x4000,
N_("Stack size when -fsplit-stack function calls non-split"),
N_("SIZE"));

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@ -2441,11 +2441,11 @@ class Stub_control
// value of the parameter --stub-group-size. If --stub-group-size
// is passed a negative value, we restrict stubs to be always after
// the stubbed branches.
Stub_control(int32_t size, bool no_size_errors)
: state_(NO_GROUP), stub_group_size_(abs(size)),
stubs_always_after_branch_(size < 0),
suppress_size_errors_(no_size_errors), group_size_(0),
group_start_addr_(0), owner_(NULL), output_section_(NULL)
Stub_control(int32_t size, bool no_size_errors, bool multi_os)
: stub_group_size_(abs(size)), stubs_always_after_branch_(size < 0),
suppress_size_errors_(no_size_errors), multi_os_(multi_os),
state_(NO_GROUP), group_size_(0), group_start_addr_(0),
owner_(NULL), output_section_(NULL)
{
}
@ -2475,15 +2475,20 @@ class Stub_control
private:
typedef enum
{
// Initial state.
NO_GROUP,
// Adding group sections before the stubs.
FINDING_STUB_SECTION,
// Adding group sections after the stubs.
HAS_STUB_SECTION
} State;
State state_;
uint32_t stub_group_size_;
bool stubs_always_after_branch_;
bool suppress_size_errors_;
// True if a stub group can serve multiple output sections.
bool multi_os_;
State state_;
// Current max size of group. Starts at stub_group_size_ but is
// reduced to stub_group_size_/1024 on seeing a section with
// external conditional branches.
@ -2537,7 +2542,19 @@ Stub_control::can_add_to_stub_group(Output_section* o,
? this_size
: (long long) end_addr - this->group_start_addr_));
if (this->state_ == HAS_STUB_SECTION)
if (this->state_ == NO_GROUP)
{
// Only here on very first use of Stub_control
this->owner_ = i;
this->output_section_ = o;
this->state_ = FINDING_STUB_SECTION;
this->group_size_ = group_size;
this->group_start_addr_ = start_addr;
return true;
}
else if (!this->multi_os_ && this->output_section_ != o)
;
else if (this->state_ == HAS_STUB_SECTION)
{
// Can we add this section, which is after the stubs, to the
// group?
@ -2571,20 +2588,13 @@ Stub_control::can_add_to_stub_group(Output_section* o,
return true;
}
}
else if (this->state_ == NO_GROUP)
{
// Only here on very first use of Stub_control
this->owner_ = i;
this->output_section_ = o;
this->state_ = FINDING_STUB_SECTION;
this->group_size_ = group_size;
this->group_start_addr_ = start_addr;
return true;
}
else
gold_unreachable();
gold_debug(DEBUG_TARGET, "nope, didn't fit\n");
gold_debug(DEBUG_TARGET,
!this->multi_os_ && this->output_section_ != o
? "nope, new output section\n"
: "nope, didn't fit\n");
// The section fails to fit in the current group. Set up a few
// things for the next group. owner_ and output_section_ will be
@ -2604,7 +2614,8 @@ Target_powerpc<size, big_endian>::group_sections(Layout* layout,
const Task*,
bool no_size_errors)
{
Stub_control stub_control(this->stub_group_size_, no_size_errors);
Stub_control stub_control(this->stub_group_size_, no_size_errors,
parameters->options().stub_group_multi());
// Group input sections and insert stub table
Stub_table_owner* table_owner = NULL;