// DAC global pointer table initialization
void DacGlobals::Initialize()
{
TADDR baseAddress = PTR_TO_TADDR(PAL_GetSymbolModuleBase((void *)DacGlobals::Initialize));
g_dacTable.InitializeEntries(baseAddress);
#ifdef FEATURE_SVR_GC
g_dacTable.InitializeSVREntries(baseAddress);
#endif
}
// DAC global pointer table initialization
void DacGlobals::Initialize()
{
TADDR baseAddress = PTR_TO_TADDR(PAL_GetSymbolModuleBase((void *)DacGlobals::Initialize));
g_dacTable.InitializeEntries(baseAddress);
#ifdef FEATURE_SVR_GC
g_dacTable.InitializeSVREntries(baseAddress);
#endif
PAL_PublishDacTableAddress((PVOID)baseAddress, &g_dacTable, sizeof(g_dacTable));
}
static bool shouldEnterCall(PTR_BYTE ip) {
SUPPORTS_DAC;
int datasize; // helper variable for decoding of address modes
int mod; // helper variable for decoding of mod r/m
int rm; // helper variable for decoding of mod r/m
int pushes = 0;
// we should start unbalenced pops within 48 instrs. If not, it is not a special epilog function
// the only reason we need as many instructions as we have below is because coreclr
// gets instrumented for profiling, code coverage, BBT etc, and we want these things to
// just work.
for (int i = 0; i < 48; i++) {
switch(*ip) {
case 0x68: // push 0xXXXXXXXX
ip += 5;
// For office profiler. They morph tail calls into push TARGET; jmp helper
// so if you see
//
// push XXXX
// jmp xxxx
//
// and we notice that coreclr has been instrumented and
// xxxx starts with a JMP [] then do what you would do for jmp XXXX
if (*ip == 0xE9 && callsInstrumented()) { // jmp helper
PTR_BYTE tmpIp = ip + 5;
PTR_BYTE target = tmpIp + (__int32)*((PTR_TADDR)(PTR_TO_TADDR(tmpIp) - 4));
if (target[0] == 0xFF && target[1] == 0x25) { // jmp [xxxx] (to external dll)
ip = PTR_BYTE(*((PTR_TADDR)(PTR_TO_TADDR(ip) - 4)));
}
}
else {
pushes++;
}
break;
case 0x50: // push EAX
case 0x51: // push ECX
case 0x52: // push EDX
case 0x53: // push EBX
case 0x55: // push EBP
case 0x56: // push ESI
case 0x57: // push EDI
pushes++;
ip++;
break;
case 0xE8: // call <disp32>
ip += 5;
pushes = 0; // This assumes that all of the previous pushes are arguments to this call
break;
case 0xFF:
if (ip[1] != 0x15) // call [XXXX] is OK (prolog of epilog helper is intrumented)
return false; // but everything else is not OK.
ip += 6;
pushes = 0; // This assumes that all of the previous pushes are arguments to this call
break;
case 0x9C: // pushfd
case 0x9D: // popfd
// a pushfd can never be an argument, so we model a pair of
// these instruction as not changing the stack so that a call
// that occurs between them does not consume the value of pushfd
ip++;
break;
case 0x5D: // pop EBP
case 0x5E: // pop ESI
case 0x5F: // pop EDI
case 0x5B: // pop EBX
case 0x58: // pop EAX
case 0x59: // pop ECX
case 0x5A: // pop EDX
if (pushes <= 0) {
// We now have more pops than pushes. This is our indication
// that we are in an EH_epilog function so we return true.
// This is the only way to exit this method with a retval of true.
return true;
}
--pushes;
ip++;
break;
case 0xA1: // MOV EAX, [XXXX]
ip += 5;
break;
case 0xC6: // MOV r/m8, imm8
datasize = 1;
goto decodeRM;
case 0x89: // MOV r/m, reg
if (ip[1] == 0xE5) // MOV EBP, ESP
return false;
if (ip[1] == 0xEC) // MOV ESP, EBP
return false;
goto move;
case 0x8B: // MOV reg, r/m
if (ip[1] == 0xE5) // MOV ESP, EBP
return false;
if (ip[1] == 0xEC) // MOV EBP, ESP
return false;
goto move;
case 0x88: // MOV reg, r/m (BYTE)
case 0x8A: // MOV r/m, reg (BYTE)
case 0x31: // XOR
case 0x32: // XOR
case 0x33: // XOR
move:
datasize = 0;
decodeRM:
// Note that we don't want to read from ip[] after
// we do ANY incrementing of ip
mod = (ip[1] & 0xC0) >> 6;
if (mod != 3) {
rm = (ip[1] & 0x07);
if (mod == 0) { // (mod == 0)
if (rm == 5)
ip += 4; // disp32
else if (rm == 4)
ip += 1; // [reg*K+reg]
// otherwise [reg]
}
else if (mod == 1) { // (mod == 1)
ip += 1; // for disp8
if (rm == 4)
ip += 1; // [reg*K+reg+disp8]
// otherwise [reg+disp8]
}
else { // (mod == 2)
ip += 4; // for disp32
if (rm == 4)
ip += 1; // [reg*K+reg+disp32]
// otherwise [reg+disp32]
}
}
ip += 2;
ip += datasize;
break;
case 0x64: // FS: prefix
ip++;
break;
case 0xEB: // jmp <disp8>
ip += (signed __int8) ip[1] + 2;
break;
case 0xE9: // jmp <disp32>
ip += (__int32)*PTR_DWORD(PTR_TO_TADDR(ip) + 1) + 5;
break;
case 0xF7: // test r/m32, imm32
// Magellan code coverage build
if ( (ip[1] & 0x38) == 0x00)
{
datasize = 4;
goto decodeRM;
}
else
{
return false;
}
break;
case 0x75: // jnz <target>
// Magellan code coverage build
// We always follow forward jump to avoid possible looping.
{
PTR_BYTE tmpIp = ip + (TADDR)(signed __int8) ip[1] + 2;
if (tmpIp > ip) {
ip = tmpIp; // follow forwards jump
}
else {
return false; // backwards jump implies not EH_epilog function
}
}
break;
case 0xC2: // ret
case 0xC3: // ret n
default:
return false;
}
}
return false;
}
