stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8284433: Cleanup Disassembler::find_prev_instr() on all platforms

Browse Source 
Reviewed-by: lucy, kvn
This commit is contained in:
Xiaolin Zheng 2022-04-08 03:23:04 +00:00 committed by Fei Yang
parent e572a525f5
commit 8c18705218
9 changed files with 0 additions and 196 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/hotspot/cpu/aarch64/disassembler_aarch64.hpp
View File

@ -34,14 +34,6 @@
return "";
}
// Returns address of n-th instruction preceding addr,
// NULL if no preceding instruction can be found.
// On ARM(aarch64), we assume a constant instruction length.
// It might be beneficial to check "is_readable" as we do on ppc and s390.
static address find_prev_instr(address addr, int n_instr) {
return addr - Assembler::instruction_size*n_instr;
}
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

8
src/hotspot/cpu/arm/disassembler_arm.hpp
View File

@ -33,14 +33,6 @@
return "";
}
// Returns address of n-th instruction preceding addr,
// NULL if no preceding instruction can be found.
// On ARM, we assume a constant instruction length.
// It might be beneficial to check "is_readable" as we do on ppc and s390.
static address find_prev_instr(address addr, int n_instr) {
return addr - Assembler::InstructionSize*n_instr;
}
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

16
src/hotspot/cpu/ppc/disassembler_ppc.cpp
View File

@ -87,22 +87,6 @@
} \
}
address Disassembler::find_prev_instr(address here, int n_instr) {
if (!os::is_readable_pointer(here)) return NULL; // obviously a bad location to decode
// Find most distant possible starting point.
// Narrow down because we don't want to SEGV while printing.
address start = here - n_instr*Assembler::instr_maxlen(); // starting point can't be further away.
while ((start < here) && !os::is_readable_range(start, here)) {
start = align_down(start, os::min_page_size()) + os::min_page_size();
}
if (start >= here) {
// Strange. Can only happen with here on page boundary.
return NULL;
}
return start;
}
address Disassembler::decode_instruction0(address here, outputStream * st, address virtual_begin ) {
if (is_abstract()) {
// The disassembler library was not loaded (yet),

9
src/hotspot/cpu/ppc/disassembler_ppc.hpp
View File

@ -34,15 +34,6 @@
return "ppc64";
}
// Find preceding instruction.
//
// Starting at the passed location, the n-th preceding (towards lower addresses)
// location is searched, the contents of which - if interpreted as
// instructions - has the passed location as n-th successor.
// - If no such location exists, NULL is returned. The caller should then
// terminate its search and react properly.
static address find_prev_instr(address here, int n_instr);
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

8
src/hotspot/cpu/riscv/disassembler_riscv.hpp
View File

@ -35,14 +35,6 @@ static const char* pd_cpu_opts() {
return "";
}
// Returns address of n-th instruction preceding addr,
// NULL if no preceding instruction can be found.
// On riscv, we assume a constant instruction length.
// It might be beneficial to check "is_readable" as we do on ppc and s390.
static address find_prev_instr(address addr, int n_instr) {
return addr - Assembler::instruction_size * n_instr;
}
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

115
src/hotspot/cpu/s390/disassembler_s390.cpp
View File

@ -36,53 +36,6 @@
#include "runtime/stubRoutines.hpp"
#include "utilities/align.hpp"
// List of all major opcodes, as of
// Principles of Operation, Eleventh Edition, March 2015
bool Disassembler::valid_opcodes[] =
{ true, true, false, false, true, true, true, true, // 0x00..07
false, false, true, true, true, true, true, true, // 0x08..0f
true, true, true, true, true, true, true, true, // 0x10..17
true, true, true, true, true, true, true, true, // 0x18..1f
true, true, true, true, true, true, true, true, // 0x20..27
true, true, true, true, true, true, true, true, // 0x28..2f
true, true, true, true, true, true, true, true, // 0x30..37
true, true, true, true, true, true, true, true, // 0x38..3f
true, true, true, true, true, true, true, true, // 0x40..47
true, true, true, true, true, true, true, true, // 0x48..4f
true, true, false, false, true, true, true, true, // 0x50..57
true, true, true, true, true, true, true, true, // 0x58..5f
true, false, false, false, false, false, false, true, // 0x60..67
true, true, true, true, true, true, true, true, // 0x68..6f
true, true, false, false, false, false, false, false, // 0x70..77
true, true, true, true, true, true, true, true, // 0x78..7f
true, false, true, true, true, true, true, true, // 0x80..87
true, true, true, true, true, true, true, true, // 0x88..8f
true, true, true, true, true, true, true, true, // 0x90..97
true, true, true, true, false, false, false, false, // 0x98..9f
false, false, false, false, false, true, false, true, // 0xa0..a7
true, true, false, false, true, true, true, true, // 0xa8..af
false, true, true, true, false, false, true, true, // 0xb0..b7
false, true, true, true, false, true, true, true, // 0xb8..bf
true, false, true, false, true, false, true, false, // 0xc0..c7
true, false, false, false, true, false, false, false, // 0xc8..cf
true, true, true, true, true, true, true, true, // 0xd0..d7
false, true, true, true, true, true, true, true, // 0xd8..df
false, true, true, true, false, true, false, true, // 0xe0..e7
true, true, true, true, true, true, true, true, // 0xe8..ef
true, true, true, true, false, false, false, false, // 0xf0..f7
true, true, true, true, true, true, false, false, // 0xf8..ff
};
// Check for valid opcodes.
//
// The major opcode (one byte) at the passed location is inspected.
// If the opcode found is assigned, the function returns true, false otherwise.
// The true indication is not reliable. It may well be that the major opcode is
// assigned, but there exists a minor opcode field in the instruction which
// which has unassigned values.
bool Disassembler::is_valid_opcode_at(address here) {
return valid_opcodes[*here];
}
// This method does plain instruction decoding, no frills.
// It may be called before the binutils disassembler kicks in
// to handle special cases the binutils disassembler does not.
@ -169,74 +122,6 @@ address Disassembler::decode_instruction0(address here, outputStream * st, addre
return next;
}
// Count the instructions contained in the range [begin..end).
// The range must exactly contain the instructions, i.e.
// - the first instruction starts @begin
// - the last instruction ends @(end-1)
// The caller has to make sure that the given range is readable.
// This function performs no safety checks!
// Return value:
// - The number of instructions, if there was exact containment.
// - If there is no exact containment, a negative value is returned.
// Its absolute value is the number of instructions from begin to end,
// where the last instruction counted runs over the range end.
// - 0 (zero) is returned if there was a parameter error
// (inverted range, bad starting point).
int Disassembler::count_instr(address begin, address end) {
if (end < begin+2) return 0; // no instructions in range
if (!Disassembler::is_valid_opcode_at(begin)) return 0; // bad starting point
address p = begin;
int n = 0;
while(p < end) {
p += Assembler::instr_len(p);
n++;
}
return (p == end) ? n : -n;
}
// Find preceding instruction.
//
// Starting at the passed location, the n-th preceding (towards lower addresses)
// instruction is searched. With variable length instructions, there may be
// more than one solution, or no solution at all (if the passed location
// does not point to the start of an instruction or if the storage area
// does not contain instructions at all).
// instructions - has the passed location as n-th successor.
// - If multiple such locations exist between (here-n*instr_maxlen()) and here,
// the most distant location is selected.
// - If no such location exists, NULL is returned. The caller should then
// terminate its search and react properly.
// Must be placed here in disassembler_s390.cpp. It does not compile
// in the header. There the class 'Assembler' is not available.
address Disassembler::find_prev_instr(address here, int n_instr) {
if (!os::is_readable_pointer(here)) return NULL; // obviously a bad location to decode
// Find most distant possible starting point.
// Narrow down because we don't want to SEGV while printing.
address start = here - n_instr*Assembler::instr_maxlen(); // starting point can't be further away.
while ((start < here) && !os::is_readable_range(start, here)) {
start = align_down(start, os::min_page_size()) + os::min_page_size();
}
if (start >= here) {
// Strange. Can only happen with here on page boundary.
return NULL;
}
//---< Find a starting point >---
int i_count = 0;
while ((start < here) && ((i_count = count_instr(start, here)) <= 0)) start += 2;
if (i_count == 0) return NULL; // There is something seriously wrong
//---< Narrow down distance (estimate was too large) >---
while(i_count-- > n_instr) {
start += Assembler::instr_len(start);
}
assert(n_instr >= count_instr(start, here), "just checking");
return start;
}
// Print annotations (value of loaded constant)
void Disassembler::annotate(address here, outputStream* st) {
// Currently, annotation doesn't work when decoding error files.

15
src/hotspot/cpu/s390/disassembler_s390.hpp
View File

@ -34,21 +34,6 @@
return "s390";
}
static bool valid_opcodes[256];
static bool is_valid_opcode_at(address here);
// Find preceding instruction.
//
// Starting at the passed location, the n-th preceding (towards lower addresses)
// location is searched, the contents of which - if interpreted as
// instructions - has the passed location as n-th successor.
// - If multiple such locations exist between (here-n*instr_maxlen()) and here,
// the most distant location is selected.
// - If no such location exists, NULL is returned. The caller should then
// terminate its search and react properly.
static address find_prev_instr(address here, int n_instr);
static int count_instr(address begin, address end);
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

9
src/hotspot/cpu/x86/disassembler_x86.hpp
View File

@ -33,15 +33,6 @@
return "";
}
// Returns address of n-th instruction preceding addr,
// NULL if no preceding instruction can be found.
// On CISC architectures, it is difficult to impossible to step
// backwards in the instruction stream. Therefore just return NULL.
// It might be beneficial to check "is_readable" as we do on ppc and s390.
static address find_prev_instr(address addr, int n_instr) {
return NULL;
}
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in

8
src/hotspot/cpu/zero/disassembler_zero.hpp
View File

@ -34,14 +34,6 @@
return "";
}
// Returns address of n-th instruction preceding addr,
// NULL if no preceding instruction can be found.
// On ZERO, we assume a constant instruction length of 1 byte.
// It might be beneficial to check "is_readable" as we do on ppc and s390.
static address find_prev_instr(address addr, int n_instr) {
return addr - 1*n_instr;
}
// special-case instruction decoding.
// There may be cases where the binutils disassembler doesn't do
// the perfect job. In those cases, decode_instruction0 may kick in