8215555: TieredCompilation C2 threads can excessively block handshakes
Reviewed-by: kvn, neliasso, rehn
/*
* Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#ifndef SHARE_VM_ASM_CODEBUFFER_HPP
#define SHARE_VM_ASM_CODEBUFFER_HPP
#include "code/oopRecorder.hpp"
#include "code/relocInfo.hpp"
#include "utilities/align.hpp"
#include "utilities/debug.hpp"
#include "utilities/macros.hpp"
class CodeStrings;
class PhaseCFG;
class Compile;
class BufferBlob;
class CodeBuffer;
class Label;
class CodeOffsets: public StackObj {
public:
enum Entries { Entry,
Verified_Entry,
Frame_Complete, // Offset in the code where the frame setup is (for forte stackwalks) is complete
OSR_Entry,
Exceptions, // Offset where exception handler lives
Deopt, // Offset where deopt handler lives
DeoptMH, // Offset where MethodHandle deopt handler lives
UnwindHandler, // Offset to default unwind handler
max_Entries };
// special value to note codeBlobs where profile (forte) stack walking is
// always dangerous and suspect.
enum { frame_never_safe = -1 };
private:
int _values[max_Entries];
public:
CodeOffsets() {
_values[Entry ] = 0;
_values[Verified_Entry] = 0;
_values[Frame_Complete] = frame_never_safe;
_values[OSR_Entry ] = 0;
_values[Exceptions ] = -1;
_values[Deopt ] = -1;
_values[DeoptMH ] = -1;
_values[UnwindHandler ] = -1;
}
int value(Entries e) { return _values[e]; }
void set_value(Entries e, int val) { _values[e] = val; }
};
// This class represents a stream of code and associated relocations.
// There are a few in each CodeBuffer.
// They are filled concurrently, and concatenated at the end.
class CodeSection {
friend class CodeBuffer;
public:
typedef int csize_t; // code size type; would be size_t except for history
private:
address _start; // first byte of contents (instructions)
address _mark; // user mark, usually an instruction beginning
address _end; // current end address
address _limit; // last possible (allocated) end address
relocInfo* _locs_start; // first byte of relocation information
relocInfo* _locs_end; // first byte after relocation information
relocInfo* _locs_limit; // first byte after relocation information buf
address _locs_point; // last relocated position (grows upward)
bool _locs_own; // did I allocate the locs myself?
bool _frozen; // no more expansion of this section
bool _scratch_emit; // Buffer is used for scratch emit, don't relocate.
char _index; // my section number (SECT_INST, etc.)
CodeBuffer* _outer; // enclosing CodeBuffer
// (Note: _locs_point used to be called _last_reloc_offset.)
CodeSection() {
_start = NULL;
_mark = NULL;
_end = NULL;
_limit = NULL;
_locs_start = NULL;
_locs_end = NULL;
_locs_limit = NULL;
_locs_point = NULL;
_locs_own = false;
_frozen = false;
_scratch_emit = false;
debug_only(_index = (char)-1);
debug_only(_outer = (CodeBuffer*)badAddress);
}
void initialize_outer(CodeBuffer* outer, int index) {
_outer = outer;
_index = index;
}
void initialize(address start, csize_t size = 0) {
assert(_start == NULL, "only one init step, please");
_start = start;
_mark = NULL;
_end = start;
_limit = start + size;
_locs_point = start;
}
void initialize_locs(int locs_capacity);
void expand_locs(int new_capacity);
void initialize_locs_from(const CodeSection* source_cs);
// helper for CodeBuffer::expand()
void take_over_code_from(CodeSection* cs) {
_start = cs->_start;
_mark = cs->_mark;
_end = cs->_end;
_limit = cs->_limit;
_locs_point = cs->_locs_point;
}
public:
address start() const { return _start; }
address mark() const { return _mark; }
address end() const { return _end; }
address limit() const { return _limit; }
csize_t size() const { return (csize_t)(_end - _start); }
csize_t mark_off() const { assert(_mark != NULL, "not an offset");
return (csize_t)(_mark - _start); }
csize_t capacity() const { return (csize_t)(_limit - _start); }
csize_t remaining() const { return (csize_t)(_limit - _end); }
relocInfo* locs_start() const { return _locs_start; }
relocInfo* locs_end() const { return _locs_end; }
int locs_count() const { return (int)(_locs_end - _locs_start); }
relocInfo* locs_limit() const { return _locs_limit; }
address locs_point() const { return _locs_point; }
csize_t locs_point_off() const{ return (csize_t)(_locs_point - _start); }
csize_t locs_capacity() const { return (csize_t)(_locs_limit - _locs_start); }
csize_t locs_remaining()const { return (csize_t)(_locs_limit - _locs_end); }
int index() const { return _index; }
bool is_allocated() const { return _start != NULL; }
bool is_empty() const { return _start == _end; }
bool is_frozen() const { return _frozen; }
bool has_locs() const { return _locs_end != NULL; }
// Mark scratch buffer.
void set_scratch_emit() { _scratch_emit = true; }
bool scratch_emit() { return _scratch_emit; }
CodeBuffer* outer() const { return _outer; }
// is a given address in this section? (2nd version is end-inclusive)
bool contains(address pc) const { return pc >= _start && pc < _end; }
bool contains2(address pc) const { return pc >= _start && pc <= _end; }
bool allocates(address pc) const { return pc >= _start && pc < _limit; }
bool allocates2(address pc) const { return pc >= _start && pc <= _limit; }
void set_end(address pc) { assert(allocates2(pc), "not in CodeBuffer memory: " INTPTR_FORMAT " <= " INTPTR_FORMAT " <= " INTPTR_FORMAT, p2i(_start), p2i(pc), p2i(_limit)); _end = pc; }
void set_mark(address pc) { assert(contains2(pc), "not in codeBuffer");
_mark = pc; }
void set_mark_off(int offset) { assert(contains2(offset+_start),"not in codeBuffer");
_mark = offset + _start; }
void set_mark() { _mark = _end; }
void clear_mark() { _mark = NULL; }
void set_locs_end(relocInfo* p) {
assert(p <= locs_limit(), "locs data fits in allocated buffer");
_locs_end = p;
}
void set_locs_point(address pc) {
assert(pc >= locs_point(), "relocation addr may not decrease");
assert(allocates2(pc), "relocation addr must be in this section");
_locs_point = pc;
}
// Code emission
void emit_int8 ( int8_t x) { *((int8_t*) end()) = x; set_end(end() + sizeof(int8_t)); }
void emit_int16( int16_t x) { *((int16_t*) end()) = x; set_end(end() + sizeof(int16_t)); }
void emit_int32( int32_t x) { *((int32_t*) end()) = x; set_end(end() + sizeof(int32_t)); }
void emit_int64( int64_t x) { *((int64_t*) end()) = x; set_end(end() + sizeof(int64_t)); }
void emit_float( jfloat x) { *((jfloat*) end()) = x; set_end(end() + sizeof(jfloat)); }
void emit_double(jdouble x) { *((jdouble*) end()) = x; set_end(end() + sizeof(jdouble)); }
void emit_address(address x) { *((address*) end()) = x; set_end(end() + sizeof(address)); }
// Share a scratch buffer for relocinfo. (Hacky; saves a resource allocation.)
void initialize_shared_locs(relocInfo* buf, int length);
// Manage labels and their addresses.
address target(Label& L, address branch_pc);
// Emit a relocation.
void relocate(address at, RelocationHolder const& rspec, int format = 0);
void relocate(address at, relocInfo::relocType rtype, int format = 0, jint method_index = 0);
// alignment requirement for starting offset
// Requirements are that the instruction area and the
// stubs area must start on CodeEntryAlignment, and
// the ctable on sizeof(jdouble)
int alignment() const { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
// Slop between sections, used only when allocating temporary BufferBlob buffers.
static csize_t end_slop() { return MAX2((int)sizeof(jdouble), (int)CodeEntryAlignment); }
csize_t align_at_start(csize_t off) const { return (csize_t) align_up(off, alignment()); }
// Mark a section frozen. Assign its remaining space to
// the following section. It will never expand after this point.
inline void freeze(); // { _outer->freeze_section(this); }
// Ensure there's enough space left in the current section.
// Return true if there was an expansion.
bool maybe_expand_to_ensure_remaining(csize_t amount);
#ifndef PRODUCT
void decode();
void dump();
void print(const char* name);
#endif //PRODUCT
};
class CodeString;
class CodeStrings {
private:
#ifndef PRODUCT
CodeString* _strings;
#ifdef ASSERT
// Becomes true after copy-out, forbids further use.
bool _defunct; // Zero bit pattern is "valid", see memset call in decode_env::decode_env
#endif
static const char* _prefix; // defaults to " ;; "
#endif
CodeString* find(intptr_t offset) const;
CodeString* find_last(intptr_t offset) const;
void set_null_and_invalidate() {
#ifndef PRODUCT
_strings = NULL;
#ifdef ASSERT
_defunct = true;
#endif
#endif
}
public:
CodeStrings() {
#ifndef PRODUCT
_strings = NULL;
#ifdef ASSERT
_defunct = false;
#endif
#endif
}
bool is_null() {
#ifdef ASSERT
return _strings == NULL;
#else
return true;
#endif
}
const char* add_string(const char * string) PRODUCT_RETURN_(return NULL;);
void add_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;
void print_block_comment(outputStream* stream, intptr_t offset) const PRODUCT_RETURN;
// MOVE strings from other to this; invalidate other.
void assign(CodeStrings& other) PRODUCT_RETURN;
// COPY strings from other to this; leave other valid.
void copy(CodeStrings& other) PRODUCT_RETURN;
// FREE strings; invalidate this.
void free() PRODUCT_RETURN;
// Guarantee that _strings are used at most once; assign and free invalidate a buffer.
inline void check_valid() const {
#ifdef ASSERT
assert(!_defunct, "Use of invalid CodeStrings");
#endif
}
static void set_prefix(const char *prefix) {
#ifndef PRODUCT
_prefix = prefix;
#endif
}
};
// A CodeBuffer describes a memory space into which assembly
// code is generated. This memory space usually occupies the
// interior of a single BufferBlob, but in some cases it may be
// an arbitrary span of memory, even outside the code cache.
//
// A code buffer comes in two variants:
//
// (1) A CodeBuffer referring to an already allocated piece of memory:
// This is used to direct 'static' code generation (e.g. for interpreter
// or stubroutine generation, etc.). This code comes with NO relocation
// information.
//
// (2) A CodeBuffer referring to a piece of memory allocated when the
// CodeBuffer is allocated. This is used for nmethod generation.
//
// The memory can be divided up into several parts called sections.
// Each section independently accumulates code (or data) an relocations.
// Sections can grow (at the expense of a reallocation of the BufferBlob
// and recopying of all active sections). When the buffered code is finally
// written to an nmethod (or other CodeBlob), the contents (code, data,
// and relocations) of the sections are padded to an alignment and concatenated.
// Instructions and data in one section can contain relocatable references to
// addresses in a sibling section.
class CodeBuffer: public StackObj {
friend class CodeSection;
friend class StubCodeGenerator;
private:
// CodeBuffers must be allocated on the stack except for a single
// special case during expansion which is handled internally. This
// is done to guarantee proper cleanup of resources.
void* operator new(size_t size) throw() { return ResourceObj::operator new(size); }
void operator delete(void* p) { ShouldNotCallThis(); }
public:
typedef int csize_t; // code size type; would be size_t except for history
enum {
// Here is the list of all possible sections. The order reflects
// the final layout.
SECT_FIRST = 0,
SECT_CONSTS = SECT_FIRST, // Non-instruction data: Floats, jump tables, etc.
SECT_INSTS, // Executable instructions.
SECT_STUBS, // Outbound trampolines for supporting call sites.
SECT_LIMIT, SECT_NONE = -1
};
private:
enum {
sect_bits = 2, // assert (SECT_LIMIT <= (1<<sect_bits))
sect_mask = (1<<sect_bits)-1
};
const char* _name;
CodeSection _consts; // constants, jump tables
CodeSection _insts; // instructions (the main section)
CodeSection _stubs; // stubs (call site support), deopt, exception handling
CodeBuffer* _before_expand; // dead buffer, from before the last expansion
BufferBlob* _blob; // optional buffer in CodeCache for generated code
address _total_start; // first address of combined memory buffer
csize_t _total_size; // size in bytes of combined memory buffer
OopRecorder* _oop_recorder;
CodeStrings _code_strings;
OopRecorder _default_oop_recorder; // override with initialize_oop_recorder
Arena* _overflow_arena;
address _last_insn; // used to merge consecutive memory barriers, loads or stores.
#if INCLUDE_AOT
bool _immutable_PIC;
#endif
address _decode_begin; // start address for decode
address decode_begin();
void initialize_misc(const char * name) {
// all pointers other than code_start/end and those inside the sections
assert(name != NULL, "must have a name");
_name = name;
_before_expand = NULL;
_blob = NULL;
_oop_recorder = NULL;
_decode_begin = NULL;
_overflow_arena = NULL;
_code_strings = CodeStrings();
_last_insn = NULL;
#if INCLUDE_AOT
_immutable_PIC = false;
#endif
}
void initialize(address code_start, csize_t code_size) {
_consts.initialize_outer(this, SECT_CONSTS);
_insts.initialize_outer(this, SECT_INSTS);
_stubs.initialize_outer(this, SECT_STUBS);
_total_start = code_start;
_total_size = code_size;
// Initialize the main section:
_insts.initialize(code_start, code_size);
assert(!_stubs.is_allocated(), "no garbage here");
assert(!_consts.is_allocated(), "no garbage here");
_oop_recorder = &_default_oop_recorder;
}
void initialize_section_size(CodeSection* cs, csize_t size);
void freeze_section(CodeSection* cs);
// helper for CodeBuffer::expand()
void take_over_code_from(CodeBuffer* cs);
// ensure sections are disjoint, ordered, and contained in the blob
void verify_section_allocation();
// copies combined relocations to the blob, returns bytes copied
// (if target is null, it is a dry run only, just for sizing)
csize_t copy_relocations_to(CodeBlob* blob) const;
// copies combined code to the blob (assumes relocs are already in there)
void copy_code_to(CodeBlob* blob);
// moves code sections to new buffer (assumes relocs are already in there)
void relocate_code_to(CodeBuffer* cb) const;
// set up a model of the final layout of my contents
void compute_final_layout(CodeBuffer* dest) const;
// Expand the given section so at least 'amount' is remaining.
// Creates a new, larger BufferBlob, and rewrites the code & relocs.
void expand(CodeSection* which_cs, csize_t amount);
// Helper for expand.
csize_t figure_expanded_capacities(CodeSection* which_cs, csize_t amount, csize_t* new_capacity);
public:
// (1) code buffer referring to pre-allocated instruction memory
CodeBuffer(address code_start, csize_t code_size) {
assert(code_start != NULL, "sanity");
initialize_misc("static buffer");
initialize(code_start, code_size);
verify_section_allocation();
}
// (2) CodeBuffer referring to pre-allocated CodeBlob.
CodeBuffer(CodeBlob* blob);
// (3) code buffer allocating codeBlob memory for code & relocation
// info but with lazy initialization. The name must be something
// informative.
CodeBuffer(const char* name) {
initialize_misc(name);
}
// (4) code buffer allocating codeBlob memory for code & relocation
// info. The name must be something informative and code_size must
// include both code and stubs sizes.
CodeBuffer(const char* name, csize_t code_size, csize_t locs_size) {
initialize_misc(name);
initialize(code_size, locs_size);
}
~CodeBuffer();
// Initialize a CodeBuffer constructed using constructor 3. Using
// constructor 4 is equivalent to calling constructor 3 and then
// calling this method. It's been factored out for convenience of
// construction.
void initialize(csize_t code_size, csize_t locs_size);
CodeSection* consts() { return &_consts; }
CodeSection* insts() { return &_insts; }
CodeSection* stubs() { return &_stubs; }
const CodeSection* insts() const { return &_insts; }
// present sections in order; return NULL at end; consts is #0, etc.
CodeSection* code_section(int n) {
// This makes the slightly questionable but portable assumption
// that the various members (_consts, _insts, _stubs, etc.) are
// adjacent in the layout of CodeBuffer.
CodeSection* cs = &_consts + n;
assert(cs->index() == n || !cs->is_allocated(), "sanity");
return cs;
}
const CodeSection* code_section(int n) const { // yucky const stuff
return ((CodeBuffer*)this)->code_section(n);
}
static const char* code_section_name(int n);
int section_index_of(address addr) const;
bool contains(address addr) const {
// handy for debugging
return section_index_of(addr) > SECT_NONE;
}
// A stable mapping between 'locators' (small ints) and addresses.
static int locator_pos(int locator) { return locator >> sect_bits; }
static int locator_sect(int locator) { return locator & sect_mask; }
static int locator(int pos, int sect) { return (pos << sect_bits) | sect; }
int locator(address addr) const;
address locator_address(int locator) const;
// Heuristic for pre-packing the taken/not-taken bit of a predicted branch.
bool is_backward_branch(Label& L);
// Properties
const char* name() const { return _name; }
void set_name(const char* name) { _name = name; }
CodeBuffer* before_expand() const { return _before_expand; }
BufferBlob* blob() const { return _blob; }
void set_blob(BufferBlob* blob);
void free_blob(); // Free the blob, if we own one.
// Properties relative to the insts section:
address insts_begin() const { return _insts.start(); }
address insts_end() const { return _insts.end(); }
void set_insts_end(address end) { _insts.set_end(end); }
address insts_limit() const { return _insts.limit(); }
address insts_mark() const { return _insts.mark(); }
void set_insts_mark() { _insts.set_mark(); }
void clear_insts_mark() { _insts.clear_mark(); }
// is there anything in the buffer other than the current section?
bool is_pure() const { return insts_size() == total_content_size(); }
// size in bytes of output so far in the insts sections
csize_t insts_size() const { return _insts.size(); }
// same as insts_size(), except that it asserts there is no non-code here
csize_t pure_insts_size() const { assert(is_pure(), "no non-code");
return insts_size(); }
// capacity in bytes of the insts sections
csize_t insts_capacity() const { return _insts.capacity(); }
// number of bytes remaining in the insts section
csize_t insts_remaining() const { return _insts.remaining(); }
// is a given address in the insts section? (2nd version is end-inclusive)
bool insts_contains(address pc) const { return _insts.contains(pc); }
bool insts_contains2(address pc) const { return _insts.contains2(pc); }
// Record any extra oops required to keep embedded metadata alive
void finalize_oop_references(const methodHandle& method);
// Allocated size in all sections, when aligned and concatenated
// (this is the eventual state of the content in its final
// CodeBlob).
csize_t total_content_size() const;
// Combined offset (relative to start of first section) of given
// section, as eventually found in the final CodeBlob.
csize_t total_offset_of(const CodeSection* cs) const;
// allocated size of all relocation data, including index, rounded up
csize_t total_relocation_size() const;
csize_t copy_relocations_to(address buf, csize_t buf_limit, bool only_inst) const;
// allocated size of any and all recorded oops
csize_t total_oop_size() const {
OopRecorder* recorder = oop_recorder();
return (recorder == NULL)? 0: recorder->oop_size();
}
// allocated size of any and all recorded metadata
csize_t total_metadata_size() const {
OopRecorder* recorder = oop_recorder();
return (recorder == NULL)? 0: recorder->metadata_size();
}
// Configuration functions, called immediately after the CB is constructed.
// The section sizes are subtracted from the original insts section.
// Note: Call them in reverse section order, because each steals from insts.
void initialize_consts_size(csize_t size) { initialize_section_size(&_consts, size); }
void initialize_stubs_size(csize_t size) { initialize_section_size(&_stubs, size); }
// Override default oop recorder.
void initialize_oop_recorder(OopRecorder* r);
OopRecorder* oop_recorder() const { return _oop_recorder; }
CodeStrings& strings() { return _code_strings; }
address last_insn() const { return _last_insn; }
void set_last_insn(address a) { _last_insn = a; }
void clear_last_insn() { set_last_insn(NULL); }
void free_strings() {
if (!_code_strings.is_null()) {
_code_strings.free(); // sets _strings Null as a side-effect.
}
}
// Code generation
void relocate(address at, RelocationHolder const& rspec, int format = 0) {
_insts.relocate(at, rspec, format);
}
void relocate(address at, relocInfo::relocType rtype, int format = 0) {
_insts.relocate(at, rtype, format);
}
// Management of overflow storage for binding of Labels.
GrowableArray<int>* create_patch_overflow();
// NMethod generation
void copy_code_and_locs_to(CodeBlob* blob) {
assert(blob != NULL, "sane");
copy_relocations_to(blob);
copy_code_to(blob);
}
void copy_values_to(nmethod* nm) {
if (!oop_recorder()->is_unused()) {
oop_recorder()->copy_values_to(nm);
}
}
// Transform an address from the code in this code buffer to a specified code buffer
address transform_address(const CodeBuffer &cb, address addr) const;
void block_comment(intptr_t offset, const char * comment) PRODUCT_RETURN;
const char* code_string(const char* str) PRODUCT_RETURN_(return NULL;);
// Log a little info about section usage in the CodeBuffer
void log_section_sizes(const char* name);
#if INCLUDE_AOT
// True if this is a code buffer used for immutable PIC, i.e. AOT
// compilation.
bool immutable_PIC() { return _immutable_PIC; }
void set_immutable_PIC(bool pic) { _immutable_PIC = pic; }
#endif
#ifndef PRODUCT
public:
// Printing / Decoding
// decodes from decode_begin() to code_end() and sets decode_begin to end
void decode();
void decode_all(); // decodes all the code
void skip_decode(); // sets decode_begin to code_end();
void print();
#endif
// The following header contains architecture-specific implementations
#include CPU_HEADER(codeBuffer)
};
inline void CodeSection::freeze() {
_outer->freeze_section(this);
}
inline bool CodeSection::maybe_expand_to_ensure_remaining(csize_t amount) {
if (remaining() < amount) { _outer->expand(this, amount); return true; }
return false;
}
#endif // SHARE_VM_ASM_CODEBUFFER_HPP