JDK14/Java14源码在线阅读
/*
* Copyright (c) 2012, 2019 SAP SE. 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.
*
*/
#include "asm/assembler.hpp"
#include "compiler/disassembler.hpp"
#include "loadlib_aix.hpp"
#include "memory/allocation.hpp"
#include "memory/allocation.inline.hpp"
#include "misc_aix.hpp"
#include "porting_aix.hpp"
#include "runtime/os.hpp"
#include "runtime/thread.hpp"
#include "utilities/align.hpp"
#include "utilities/debug.hpp"
// distinguish old xlc and xlclang++, where
// <ibmdemangle.h> is suggested but not found in GA release (might come with a fix)
#if defined(__clang__)
#define DISABLE_DEMANGLE
// #include <ibmdemangle.h>
#else
#include <demangle.h>
#endif
#include <sys/debug.h>
#include <pthread.h>
#include <ucontext.h>
//////////////////////////////////
// Provide implementation for dladdr based on LoadedLibraries pool and
// traceback table scan
// Search traceback table in stack,
// return procedure name from trace back table.
#define MAX_FUNC_SEARCH_LEN 0x10000
#define PTRDIFF_BYTES(p1,p2) (((ptrdiff_t)p1) - ((ptrdiff_t)p2))
// Typedefs for stackslots, stack pointers, pointers to op codes.
typedef unsigned long stackslot_t;
typedef stackslot_t* stackptr_t;
typedef unsigned int* codeptr_t;
// Unfortunately, the interface of dladdr makes the implementator
// responsible for maintaining memory for function name/library
// name. I guess this is because most OS's keep those values as part
// of the mapped executable image ready to use. On AIX, this doesn't
// work, so I have to keep the returned strings. For now, I do this in
// a primitive string map. Should this turn out to be a performance
// problem, a better hashmap has to be used.
class fixed_strings {
struct node : public CHeapObj<mtInternal> {
char* v;
node* next;
};
node* first;
public:
fixed_strings() : first(0) {}
~fixed_strings() {
node* n = first;
while (n) {
node* p = n;
n = n->next;
os::free(p->v);
delete p;
}
}
char* intern(const char* s) {
for (node* n = first; n; n = n->next) {
if (strcmp(n->v, s) == 0) {
return n->v;
}
}
node* p = new node;
p->v = os::strdup_check_oom(s);
p->next = first;
first = p;
return p->v;
}
};
static fixed_strings dladdr_fixed_strings;
bool AixSymbols::get_function_name (
address pc0, // [in] program counter
char* p_name, size_t namelen, // [out] optional: function name ("" if not available)
int* p_displacement, // [out] optional: displacement (-1 if not available)
const struct tbtable** p_tb, // [out] optional: ptr to traceback table to get further
// information (NULL if not available)
bool demangle // [in] whether to demangle the name
) {
struct tbtable* tb = 0;
unsigned int searchcount = 0;
// initialize output parameters
if (p_name && namelen > 0) {
*p_name = '\0';
}
if (p_displacement) {
*p_displacement = -1;
}
if (p_tb) {
*p_tb = NULL;
}
codeptr_t pc = (codeptr_t)pc0;
// weed out obvious bogus states
if (pc < (codeptr_t)0x1000) {
trcVerbose("invalid program counter");
return false;
}
// We see random but frequent crashes in this function since some months mainly on shutdown
// (-XX:+DumpInfoAtExit). It appears the page we are reading is randomly disappearing while
// we read it (?).
// As the pc cannot be trusted to be anything sensible lets make all reads via SafeFetch. Also
// bail if this is not a text address right now.
if (!LoadedLibraries::find_for_text_address(pc, NULL)) {
trcVerbose("not a text address");
return false;
}
// .. (Note that is_readable_pointer returns true if safefetch stubs are not there yet;
// in that case I try reading the traceback table unsafe - I rather risk secondary crashes in
// error files than not having a callstack.)
#define CHECK_POINTER_READABLE(p) \
if (!os::is_readable_pointer(p)) { \
trcVerbose("pc not readable"); \
return false; \
}
codeptr_t pc2 = (codeptr_t) pc;
// Make sure the pointer is word aligned.
pc2 = (codeptr_t) align_up((char*)pc2, 4);
CHECK_POINTER_READABLE(pc2)
// Find start of traceback table.
// (starts after code, is marked by word-aligned (32bit) zeros)
while ((*pc2 != NULL) && (searchcount++ < MAX_FUNC_SEARCH_LEN)) {
CHECK_POINTER_READABLE(pc2)
pc2++;
}
if (*pc2 != 0) {
trcVerbose("no traceback table found");
return false;
}
//
// Set up addressability to the traceback table
//
tb = (struct tbtable*) (pc2 + 1);
// Is this really a traceback table? No way to be sure but
// some indicators we can check.
if (tb->tb.lang >= 0xf && tb->tb.lang <= 0xfb) {
// Language specifiers, go from 0 (C) to 14 (Objective C).
// According to spec, 0xf-0xfa reserved, 0xfb-0xff reserved for ibm.
trcVerbose("no traceback table found");
return false;
}
// Existence of fields in the tbtable extension are contingent upon
// specific fields in the base table. Check for their existence so
// that we can address the function name if it exists.
pc2 = (codeptr_t) tb +
sizeof(struct tbtable_short)/sizeof(int);
if (tb->tb.fixedparms != 0 || tb->tb.floatparms != 0)
pc2++;
CHECK_POINTER_READABLE(pc2)
if (tb->tb.has_tboff == TRUE) {
// I want to know the displacement
const unsigned int tb_offset = *pc2;
codeptr_t start_of_procedure =
(codeptr_t)(((char*)tb) - 4 - tb_offset); // (-4 to omit leading 0000)
// Weed out the cases where we did find the wrong traceback table.
if (pc < start_of_procedure) {
trcVerbose("no traceback table found");
return false;
}
// return the displacement
if (p_displacement) {
(*p_displacement) = (int) PTRDIFF_BYTES(pc, start_of_procedure);
}
pc2++;
} else {
// return -1 for displacement
if (p_displacement) {
(*p_displacement) = -1;
}
}
if (tb->tb.int_hndl == TRUE)
pc2++;
if (tb->tb.has_ctl == TRUE)
pc2 += (*pc2) + 1; // don't care
CHECK_POINTER_READABLE(pc2)
//
// return function name if it exists.
//
if (p_name && namelen > 0) {
if (tb->tb.name_present) {
// Copy name from text because it may not be zero terminated.
const short l = MIN2<short>(*((short*)pc2), namelen - 1);
// Be very careful.
int i = 0; char* const p = (char*)pc2 + sizeof(short);
while (i < l && os::is_readable_pointer(p + i)) {
p_name[i] = p[i];
i++;
}
p_name[i] = '\0';
// If it is a C++ name, try and demangle it using the Demangle interface (see demangle.h).
#ifndef DISABLE_DEMANGLE
if (demangle) {
char* rest;
Name* const name = Demangle(p_name, rest);
if (name) {
const char* const demangled_name = name->Text();
if (demangled_name) {
strncpy(p_name, demangled_name, namelen-1);
p_name[namelen-1] = '\0';
}
delete name;
}
}
#endif
} else {
strncpy(p_name, "<nameless function>", namelen-1);
p_name[namelen-1] = '\0';
}
}
// Return traceback table, if user wants it.
if (p_tb) {
(*p_tb) = tb;
}
return true;
}
bool AixSymbols::get_module_name(address pc,
char* p_name, size_t namelen) {
if (p_name && namelen > 0) {
p_name[0] = '\0';
loaded_module_t lm;
if (LoadedLibraries::find_for_text_address(pc, &lm) != NULL) {
strncpy(p_name, lm.shortname, namelen);
p_name[namelen - 1] = '\0';
return true;
}
}
return false;
}
// Special implementation of dladdr for Aix based on LoadedLibraries
// Note: dladdr returns non-zero for ok, 0 for error!
// Note: dladdr is not posix, but a non-standard GNU extension. So this tries to
// fulfill the contract of dladdr on Linux (see http://linux.die.net/man/3/dladdr)
// Note: addr may be both an AIX function descriptor or a real code pointer
// to the entry of a function.
extern "C"
int dladdr(void* addr, Dl_info* info) {
if (!addr) {
return 0;
}
assert(info, "");
int rc = 0;
const char* const ZEROSTRING = "";
// Always return a string, even if a "" one. Linux dladdr manpage
// does not say anything about returning NULL
info->dli_fname = ZEROSTRING;
info->dli_sname = ZEROSTRING;
info->dli_saddr = NULL;
address p = (address) addr;
loaded_module_t lm;
bool found = false;
enum { noclue, code, data } type = noclue;
trcVerbose("dladdr(%p)...", p);
// Note: input address may be a function. I accept both a pointer to
// the entry of a function and a pointer to the function decriptor.
// (see ppc64 ABI)
found = LoadedLibraries::find_for_text_address(p, &lm);
if (found) {
type = code;
}
if (!found) {
// Not a pointer into any text segment. Is it a function descriptor?
const FunctionDescriptor* const pfd = (const FunctionDescriptor*) p;
p = pfd->entry();
if (p) {
found = LoadedLibraries::find_for_text_address(p, &lm);
if (found) {
type = code;
}
}
}
if (!found) {
// Neither direct code pointer nor function descriptor. A data ptr?
p = (address)addr;
found = LoadedLibraries::find_for_data_address(p, &lm);
if (found) {
type = data;
}
}
// If we did find the shared library this address belongs to (either
// code or data segment) resolve library path and, if possible, the
// symbol name.
if (found) {
// No need to intern the libpath, that one is already interned one layer below.
info->dli_fname = lm.path;
if (type == code) {
// For code symbols resolve function name and displacement. Use
// displacement to calc start of function.
char funcname[256] = "";
int displacement = 0;
if (AixSymbols::get_function_name(p, funcname, sizeof(funcname),
&displacement, NULL, true)) {
if (funcname[0] != '\0') {
const char* const interned = dladdr_fixed_strings.intern(funcname);
info->dli_sname = interned;
trcVerbose("... function name: %s ...", interned);
}
// From the displacement calculate the start of the function.
if (displacement != -1) {
info->dli_saddr = p - displacement;
} else {
info->dli_saddr = p;
}
} else {
// No traceback table found. Just assume the pointer is it.
info->dli_saddr = p;
}
} else if (type == data) {
// For data symbols.
info->dli_saddr = p;
} else {
ShouldNotReachHere();
}
rc = 1; // success: return 1 [sic]
}
// sanity checks.
if (rc) {
assert(info->dli_fname, "");
assert(info->dli_sname, "");
assert(info->dli_saddr, "");
}
return rc; // error: return 0 [sic]
}
/////////////////////////////////////////////////////////////////////////////
// Native callstack dumping
// Print the traceback table for one stack frame.
static void print_tbtable (outputStream* st, const struct tbtable* p_tb) {
if (p_tb == NULL) {
st->print("<null>");
return;
}
switch(p_tb->tb.lang) {
case TB_C: st->print("C"); break;
case TB_FORTRAN: st->print("FORTRAN"); break;
case TB_PASCAL: st->print("PASCAL"); break;
case TB_ADA: st->print("ADA"); break;
case TB_PL1: st->print("PL1"); break;
case TB_BASIC: st->print("BASIC"); break;
case TB_LISP: st->print("LISP"); break;
case TB_COBOL: st->print("COBOL"); break;
case TB_MODULA2: st->print("MODULA2"); break;
case TB_CPLUSPLUS: st->print("C++"); break;
case TB_RPG: st->print("RPG"); break;
case TB_PL8: st->print("PL8"); break;
case TB_ASM: st->print("ASM"); break;
case TB_HPJ: st->print("HPJ"); break;
default: st->print("unknown");
}
st->print(" ");
if (p_tb->tb.globallink) {
st->print("globallink ");
}
if (p_tb->tb.is_eprol) {
st->print("eprol ");
}
if (p_tb->tb.int_proc) {
st->print("int_proc ");
}
if (p_tb->tb.tocless) {
st->print("tocless ");
}
if (p_tb->tb.fp_present) {
st->print("fp_present ");
}
if (p_tb->tb.int_hndl) {
st->print("interrupt_handler ");
}
if (p_tb->tb.uses_alloca) {
st->print("uses_alloca ");
}
if (p_tb->tb.saves_cr) {
st->print("saves_cr ");
}
if (p_tb->tb.saves_lr) {
st->print("saves_lr ");
}
if (p_tb->tb.stores_bc) {
st->print("stores_bc ");
}
if (p_tb->tb.fixup) {
st->print("fixup ");
}
if (p_tb->tb.fpr_saved > 0) {
st->print("fpr_saved:%d ", p_tb->tb.fpr_saved);
}
if (p_tb->tb.gpr_saved > 0) {
st->print("gpr_saved:%d ", p_tb->tb.gpr_saved);
}
if (p_tb->tb.fixedparms > 0) {
st->print("fixedparms:%d ", p_tb->tb.fixedparms);
}
if (p_tb->tb.floatparms > 0) {
st->print("floatparms:%d ", p_tb->tb.floatparms);
}
if (p_tb->tb.parmsonstk > 0) {
st->print("parmsonstk:%d", p_tb->tb.parmsonstk);
}
}
// Print information for pc (module, function, displacement, traceback table)
// on one line.
static void print_info_for_pc (outputStream* st, codeptr_t pc, char* buf,
size_t buf_size, bool demangle) {
const struct tbtable* tb = NULL;
int displacement = -1;
if (!os::is_readable_pointer(pc)) {
st->print("(invalid)");
return;
}
if (AixSymbols::get_module_name((address)pc, buf, buf_size)) {
st->print("%s", buf);
} else {
st->print("(unknown module)");
}
st->print("::");
if (AixSymbols::get_function_name((address)pc, buf, buf_size,
&displacement, &tb, demangle)) {
st->print("%s", buf);
} else {
st->print("(unknown function)");
}
if (displacement == -1) {
st->print("+?");
} else {
st->print("+0x%x", displacement);
}
if (tb) {
st->fill_to(64);
st->print(" (");
print_tbtable(st, tb);
st->print(")");
}
}
static void print_stackframe(outputStream* st, stackptr_t sp, char* buf,
size_t buf_size, bool demangle) {
stackptr_t sp2 = sp;
// skip backchain
sp2++;
// skip crsave
sp2++;
// retrieve lrsave. That is the only info I need to get the function/displacement
codeptr_t lrsave = (codeptr_t) *(sp2);
st->print (PTR64_FORMAT " - " PTR64_FORMAT " ", sp2, lrsave);
if (lrsave != NULL) {
print_info_for_pc(st, lrsave, buf, buf_size, demangle);
}
}
// Function to check a given stack pointer against given stack limits.
static bool is_valid_stackpointer(stackptr_t sp, stackptr_t stack_base, size_t stack_size) {
if (((uintptr_t)sp) & 0x7) {
return false;
}
if (sp > stack_base) {
return false;
}
if (sp < (stackptr_t) ((address)stack_base - stack_size)) {
return false;
}
return true;
}
// Returns true if function is a valid codepointer.
static bool is_valid_codepointer(codeptr_t p) {
if (!p) {
return false;
}
if (((uintptr_t)p) & 0x3) {
return false;
}
if (LoadedLibraries::find_for_text_address(p, NULL) == NULL) {
return false;
}
return true;
}
// Function tries to guess if the given combination of stack pointer, stack base
// and stack size is a valid stack frame.
static bool is_valid_frame (stackptr_t p, stackptr_t stack_base, size_t stack_size) {
if (!is_valid_stackpointer(p, stack_base, stack_size)) {
return false;
}
// First check - the occurrence of a valid backchain pointer up the stack, followed by a
// valid codeptr, counts as a good candidate.
stackptr_t sp2 = (stackptr_t) *p;
if (is_valid_stackpointer(sp2, stack_base, stack_size) && // found a valid stack pointer in the stack...
((sp2 - p) > 6) && // ... pointing upwards and not into my frame...
is_valid_codepointer((codeptr_t)(*(sp2 + 2)))) // ... followed by a code pointer after two slots...
{
return true;
}
return false;
}
// Try to relocate a stack back chain in a given stack.
// Used in callstack dumping, when the backchain is broken by an overwriter
static stackptr_t try_find_backchain (stackptr_t last_known_good_frame,
stackptr_t stack_base, size_t stack_size)
{
if (!is_valid_stackpointer(last_known_good_frame, stack_base, stack_size)) {
return NULL;
}
stackptr_t sp = last_known_good_frame;
sp += 6; // Omit next fixed frame slots.
while (sp < stack_base) {
if (is_valid_frame(sp, stack_base, stack_size)) {
return sp;
}
sp ++;
}
return NULL;
}
static void decode_instructions_at_pc(const char* header,
codeptr_t pc, int num_before,
int num_after, outputStream* st) {
// TODO: PPC port Disassembler::decode(pc, 16, 16, st);
}
void AixNativeCallstack::print_callstack_for_context(outputStream* st, const ucontext_t* context,
bool demangle, char* buf, size_t buf_size) {
#define MAX_CALLSTACK_DEPTH 50
unsigned long* sp;
unsigned long* sp_last;
int frame;
// To print the first frame, use the current value of iar:
// current entry indicated by iar (the current pc)
codeptr_t cur_iar = 0;
stackptr_t cur_sp = 0;
codeptr_t cur_rtoc = 0;
codeptr_t cur_lr = 0;
const ucontext_t* uc = (const ucontext_t*) context;
// fallback: use the current context
ucontext_t local_context;
if (!uc) {
st->print_cr("No context given, using current context.");
if (getcontext(&local_context) == 0) {
uc = &local_context;
} else {
st->print_cr("No context given and getcontext failed. ");
return;
}
}
cur_iar = (codeptr_t)uc->uc_mcontext.jmp_context.iar;
cur_sp = (stackptr_t)uc->uc_mcontext.jmp_context.gpr[1];
cur_rtoc = (codeptr_t)uc->uc_mcontext.jmp_context.gpr[2];
cur_lr = (codeptr_t)uc->uc_mcontext.jmp_context.lr;
// syntax used here:
// n -------------- <-- stack_base, stack_to
// n-1 | |
// ... | older |
// ... | frames | |
// | | | stack grows downward
// ... | younger | |
// ... | frames | V
// | |
// |------------| <-- cur_sp, current stack ptr
// | |
// | unsused |
// | stack |
// | |
// . .
// . .
// . .
// . .
// | |
// 0 -------------- <-- stack_from
//
// Retrieve current stack base, size from the current thread. If there is none,
// retrieve it from the OS.
stackptr_t stack_base = NULL;
size_t stack_size = NULL;
{
AixMisc::stackbounds_t stackbounds;
if (!AixMisc::query_stack_bounds_for_current_thread(&stackbounds)) {
st->print_cr("Cannot retrieve stack bounds.");
return;
}
stack_base = (stackptr_t)stackbounds.base;
stack_size = stackbounds.size;
}
st->print_cr("------ current frame:");
st->print("iar: " PTR64_FORMAT " ", p2i(cur_iar));
print_info_for_pc(st, cur_iar, buf, buf_size, demangle);
st->cr();
if (cur_iar && os::is_readable_pointer(cur_iar)) {
decode_instructions_at_pc(
"Decoded instructions at iar:",
cur_iar, 32, 16, st);
}
// Print out lr too, which may be interesting if we did jump to some bogus location;
// in those cases the new frame is not built up yet and the caller location is only
// preserved via lr register.
st->print("lr: " PTR64_FORMAT " ", p2i(cur_lr));
print_info_for_pc(st, cur_lr, buf, buf_size, demangle);
st->cr();
if (cur_lr && os::is_readable_pointer(cur_lr)) {
decode_instructions_at_pc(
"Decoded instructions at lr:",
cur_lr, 32, 16, st);
}
// Check and print sp.
st->print("sp: " PTR64_FORMAT " ", p2i(cur_sp));
if (!is_valid_stackpointer(cur_sp, stack_base, stack_size)) {
st->print("(invalid) ");
goto cleanup;
} else {
st->print("(base - 0x%X) ", PTRDIFF_BYTES(stack_base, cur_sp));
}
st->cr();
// Check and print rtoc.
st->print("rtoc: " PTR64_FORMAT " ", p2i(cur_rtoc));
if (cur_rtoc == NULL || cur_rtoc == (codeptr_t)-1 ||
!os::is_readable_pointer(cur_rtoc)) {
st->print("(invalid)");
} else if (((uintptr_t)cur_rtoc) & 0x7) {
st->print("(unaligned)");
}
st->cr();
st->print_cr("|---stackaddr----| |----lrsave------|: <function name>");
///
// Walk callstack.
//
// (if no context was given, use the current stack)
sp = (unsigned long*)(*(unsigned long*)cur_sp); // Stack pointer
sp_last = cur_sp;
frame = 0;
while (frame < MAX_CALLSTACK_DEPTH) {
// Check sp.
bool retry = false;
if (sp == NULL) {
// The backchain pointer was NULL. This normally means the end of the chain. But the
// stack might be corrupted, and it may be worth looking for the stack chain.
if (is_valid_stackpointer(sp_last, stack_base, stack_size) && (stack_base - 0x10) > sp_last) {
// If we are not within <guess> 0x10 stackslots of the stack base, we assume that this
// is indeed not the end of the chain but that the stack was corrupted. So lets try to
// find the end of the chain.
st->print_cr("*** back chain pointer is NULL - end of stack or broken backchain ? ***");
retry = true;
} else {
st->print_cr("*** end of backchain ***");
goto end_walk_callstack;
}
} else if (!is_valid_stackpointer(sp, stack_base, stack_size)) {
st->print_cr("*** stack pointer invalid - backchain corrupted (" PTR_FORMAT ") ***", p2i(sp));
retry = true;
} else if (sp < sp_last) {
st->print_cr("invalid stack pointer: " PTR_FORMAT " (not monotone raising)", p2i(sp));
retry = true;
}
// If backchain is broken, try to recover, by manually scanning the stack for a pattern
// which looks like a valid stack.
if (retry) {
st->print_cr("trying to recover and find backchain...");
sp = try_find_backchain(sp_last, stack_base, stack_size);
if (sp) {
st->print_cr("found something which looks like a backchain at " PTR64_FORMAT ", after 0x%x bytes... ",
p2i(sp), PTRDIFF_BYTES(sp, sp_last));
} else {
st->print_cr("did not find a backchain, giving up.");
goto end_walk_callstack;
}
}
// Print stackframe.
print_stackframe(st, sp, buf, buf_size, demangle);
st->cr();
frame ++;
// Next stack frame and link area.
sp_last = sp;
sp = (unsigned long*)(*sp);
}
// Prevent endless loops in case of invalid callstacks.
if (frame == MAX_CALLSTACK_DEPTH) {
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java