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[GOLD] PowerPC --stub-group-multi
- From: Alan Modra <amodra at gmail dot com>
- To: binutils at sourceware dot org
- Date: Wed, 7 Dec 2016 15:04:44 +1030
- Subject: [GOLD] PowerPC --stub-group-multi
- Authentication-results: sourceware.org; auth=none
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.
diff --git a/gold/options.h b/gold/options.h
index 90ccc80..6722667 100644
--- a/gold/options.h
+++ b/gold/options.h
@@ -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"));
diff --git a/gold/powerpc.cc b/gold/powerpc.cc
index f763618..068f5ca 100644
--- a/gold/powerpc.cc
+++ b/gold/powerpc.cc
@@ -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;
--
Alan Modra
Australia Development Lab, IBM