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Implement two new switch idioms closes #14

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This commit is contained in:
nemerle 2016-04-23 20:05:11 +02:00
parent 5c85c92d1a
commit 12ee08f87e
3 changed files with 2018 additions and 1837 deletions
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3
include/Procedure.h
View File

@ -233,6 +233,9 @@ protected:
void genLiveKtes();
bool findDerivedSeq(derSeq &derivedGi);
bool nextOrderGraph(derSeq &derivedGi);
private:
bool decodeIndirectJMP(ICODE &pIcode, STATE *pstate, CALL_GRAPH *pcallGraph);
bool decodeIndirectJMP2(ICODE &pIcode, STATE *pstate, CALL_GRAPH *pcallGraph);
};
namespace llvm {
template<> struct ilist_traits<typename ::Function>

2
src/DccFrontend.cpp
View File

@ -371,7 +371,7 @@ void DccFrontend::parse(Project &proj)
/* Check for special settings of initial state, based on idioms of the
startup code */
state.checkStartup();
Function *start_proc;
ilFunction start_proc;
/* Make a struct for the initial procedure */
if (prog.offMain != -1)
{

190
src/parser.cpp
View File

@ -9,6 +9,9 @@
#include <sstream>
#include <stdio.h>
#include <algorithm>
#include <deque>
#include <QMap>
#include <QtCore/QDebug>
#include "dcc.h"
#include "project.h"
@ -193,11 +196,9 @@ void Function::FollowCtrl(CALL_GRAPH * pcallGraph, STATE *pstate)
pstate->JCond.immed++;
if (ll->getOpcode() == iJAE || ll->getOpcode() == iJA)
pstate->JCond.regi = prev.ll()->m_dst.regi;
fBranch = (bool)
(ll->getOpcode() == iJB || ll->getOpcode() == iJBE);
fBranch = (bool) (ll->getOpcode() == iJB || ll->getOpcode() == iJBE);
}
StCopy = *pstate;
//memcpy(&StCopy, pstate, sizeof(STATE));
/* Straight line code */
this->FollowCtrl (pcallGraph, &StCopy); // recurrent ?
@ -367,6 +368,178 @@ bool Function::followAllTableEntries(JumpTable &table, uint32_t cs, ICODE& pIcod
}
return true;
}
bool Function::decodeIndirectJMP(ICODE & pIcode, STATE *pstate, CALL_GRAPH * pcallGraph)
{
PROG &prog(Project::get()->prog);
// mov cx,NUM_CASES
// mov bx,JUMP_TABLE
// LAB1:
// mov ax, [bx]
// cmp ax,VAL
// jz LAB2
// add bx,2
// loop LAB1
// jmp DEFAULT_CASE
// LAB2
// jmp word ptr [bx+2*NUM_CASES]
static const llIcode match_seq[] = {iMOV,iMOV,iMOV,iCMP,iJE,iADD,iLOOP,iJMP,iJMP};
if(Icode.size()<8)
return false;
if(&Icode.back()!=&pIcode) // not the last insn in the list skip it
return false;
if(pIcode.ll()->src().regi != INDEX_BX) {
return false;
}
// find address-wise predecessors of the icode
std::deque<ICODE *> matched;
QMap<uint32_t,ICODE *> addrmap;
for(ICODE & ic : Icode) {
addrmap[ic.ll()->GetLlLabel()] = &ic;
}
auto iter = addrmap.find(pIcode.ll()->GetLlLabel());
while(matched.size()<9) {
matched.push_front(*iter);
--iter;
if(iter==addrmap.end())
return false;
}
// pattern starts at the last jmp
ICODE *load_num_cases = matched[0];
ICODE *load_jump_table_addr = matched[1];
ICODE *read_case_entry_insn = matched[2];
ICODE *cmp_case_val_insn = matched[3];
ICODE *exit_loop_insn = matched[4];
ICODE *add_bx_insn = matched[5];
ICODE *loop_insn = matched[6];
ICODE *default_jmp = matched[7];
ICODE *last_jmp = matched[8];
for(int i=0; i<8; ++i) {
if(matched[i+1]->ll()->GetLlLabel()!=matched[i]->ll()->GetLlLabel()+matched[i]->ll()->numBytes) {
qDebug() << "Matching jump pattern impossible - undecoded instructions in pattern area ";
return false;
}
}
for(int i=0; i<9; ++i) {
if(matched[i]->ll()->getOpcode()!=match_seq[i]) {
return false;
}
}
// verify that bx+offset == 2* case count
uint32_t num_cases = load_num_cases->ll()->src().getImm2();
if(last_jmp->ll()->src().off != 2*num_cases)
return false;
const LLOperand &op = last_jmp->ll()->src();
if(op.regi != INDEX_BX)
return false;
if(!load_jump_table_addr->ll()->src().isImmediate())
return false;
uint32_t cs = (uint32_t)(uint16_t)pstate->r[rCS] << 4;
uint32_t table_addr = cs + load_jump_table_addr->ll()->src().getImm2();
uint32_t default_label = cs + default_jmp->ll()->src().getImm2();
setBits(BM_DATA, table_addr, num_cases*2 + num_cases*2); // num_cases of short values + num cases short ptrs
pIcode.ll()->setFlags(SWITCH);
for(int i=0; i<num_cases; ++i) {
STATE StCopy = *pstate;
uint32_t jump_target_location = table_addr + num_cases*2 + i*2;
StCopy.IP = cs + *(uint16_t *)(prog.image()+jump_target_location);
iICODE last_current_insn = (++Icode.rbegin()).base();
FollowCtrl (pcallGraph, &StCopy);
++last_current_insn;
last_current_insn->ll()->caseEntry = i;
last_current_insn->ll()->setFlags(CASE);
pIcode.ll()->caseTbl2.push_back( last_current_insn->ll()->GetLlLabel() );
}
return true;
}
bool Function::decodeIndirectJMP2(ICODE & pIcode, STATE *pstate, CALL_GRAPH * pcallGraph)
{
PROG &prog(Project::get()->prog);
// mov cx,NUM_CASES
// mov bx,JUMP_TABLE
// LAB1:
// mov ax, [bx]
// cmp ax, LOW_WORD_OF_VAL
// jnz LAB2
// mov ax, [bx + 2 * NUM_CASES]
// cmp ax, HIGH_WORD_OF_VAL
// jz LAB3
// LAB2
// add bx,2
// loop LAB1
// jmp DEFAULT_CASE
// LAB3
// jmp word ptr [bx+2*NUM_CASES]
static const llIcode match_seq[] = {iMOV,iMOV,iMOV,iCMP,iJNE,iMOV,iCMP,iJE,iADD,iLOOP,iJMP,iJMP};
if(Icode.size()<12)
return false;
if(&Icode.back()!=&pIcode) // not the last insn in the list skip it
return false;
if(pIcode.ll()->src().regi != INDEX_BX) {
return false;
}
// find address-wise predecessors of the icode
std::deque<ICODE *> matched;
QMap<uint32_t,ICODE *> addrmap;
for(ICODE & ic : Icode) {
addrmap[ic.ll()->GetLlLabel()] = &ic;
}
auto iter = addrmap.find(pIcode.ll()->GetLlLabel());
while(matched.size()<12) {
matched.push_front(*iter);
--iter;
if(iter==addrmap.end())
return false;
}
// pattern starts at the last jmp
ICODE *load_num_cases = matched[0];
ICODE *load_jump_table_addr = matched[1];
ICODE *default_jmp = matched[10];
ICODE *last_jmp = matched[11];
for(int i=0; i<11; ++i) {
if(matched[i+1]->ll()->GetLlLabel()!=matched[i]->ll()->GetLlLabel()+matched[i]->ll()->numBytes) {
qDebug() << "Matching jump pattern impossible - undecoded instructions in pattern area ";
return false;
}
}
for(int i=0; i<12; ++i) {
if(matched[i]->ll()->getOpcode()!=match_seq[i]) {
return false;
}
}
// verify that bx+offset == 2* case count
uint32_t num_cases = load_num_cases->ll()->src().getImm2();
if(last_jmp->ll()->src().off != 4*num_cases)
return false;
const LLOperand &op = last_jmp->ll()->src();
if(op.regi != INDEX_BX)
return false;
if(!load_jump_table_addr->ll()->src().isImmediate())
return false;
uint32_t cs = (uint32_t)(uint16_t)pstate->r[rCS] << 4;
uint32_t table_addr = cs + load_jump_table_addr->ll()->src().getImm2();
int default_label = cs + default_jmp->ll()->src().getImm2();
setBits(BM_DATA, table_addr, num_cases*4 + num_cases*2); // num_cases of long values + num cases short ptrs
pIcode.ll()->setFlags(SWITCH);
for(int i=0; i<num_cases; ++i) {
STATE StCopy = *pstate;
uint32_t jump_target_location = table_addr + num_cases*4 + i*2;
StCopy.IP = cs + *(uint16_t *)(prog.image()+jump_target_location);
iICODE last_current_insn = (++Icode.rbegin()).base();
FollowCtrl (pcallGraph, &StCopy);
++last_current_insn;
last_current_insn->ll()->caseEntry = i;
last_current_insn->ll()->setFlags(CASE);
pIcode.ll()->caseTbl2.push_back( last_current_insn->ll()->GetLlLabel() );
}
return true;
}
bool Function::process_JMP (ICODE & pIcode, STATE *pstate, CALL_GRAPH * pcallGraph)
{
@ -390,14 +563,13 @@ bool Function::process_JMP (ICODE & pIcode, STATE *pstate, CALL_GRAPH * pcallGra
/* Return true if jump target is already parsed */
return Icode.alreadyDecoded(i);
}
/* We've got an indirect JMP - look for switch() stmt. idiom of the form
* JMP uint16_t ptr word_offset[rBX | rSI | rDI] */
seg = (pIcode.ll()->src().seg)? pIcode.ll()->src().seg: rDS;
/* Ensure we have a uint16_t offset & valid seg */
if (pIcode.ll()->match(iJMP) and (pIcode.ll()->testFlags(WORD_OFF)) &&
pstate->f[seg] &&
if (pIcode.ll()->match(iJMP) and (pIcode.ll()->testFlags(WORD_OFF)) and
pstate->f[seg] and
(pIcode.ll()->src().regi == INDEX_SI ||
pIcode.ll()->src().regi == INDEX_DI || /* Idx reg. BX, SI, DI */
pIcode.ll()->src().regi == INDEX_BX))
@ -475,6 +647,12 @@ bool Function::process_JMP (ICODE & pIcode, STATE *pstate, CALL_GRAPH * pcallGra
return true;
}
}
if(decodeIndirectJMP(pIcode,pstate,pcallGraph)) {
return true;
}
if(decodeIndirectJMP2(pIcode,pstate,pcallGraph)) {
return true;
}
/* Can't do anything with this jump */