Index: vm_x86.c
===================================================================
--- vm_x86.c (revision 1972)
+++ vm_x86.c (working copy)
@@ -107,6 +107,10 @@
static ELastCommand LastCommand;
+static void ErrJump( void ) { Com_Error( ERR_DROP, "program tried to execute code outside VM\n" ); }
+
+static void (*const errJumpPtr)(void) = ErrJump;
+
/*
=================
AsmCall
@@ -124,13 +128,21 @@
sub edi, 4
test eax,eax
jl systemCall
+ cmp eax, [callMask]
+ jae badAddr
// calling another vm function
shl eax,2
add eax, dword ptr [instructionPointers]
call dword ptr [eax]
mov eax, dword ptr [edi]
- and eax, [callMask]
ret
+badAddr:
+ call ErrJump
+ // leave something on the opstack
+ //add edi, 4
+ //mov dword ptr [edi], 0
+ //ret
+
systemCall:
// convert negative num to system call number
@@ -212,12 +224,18 @@
"subl $4, %edi\n\t"
"testl %eax, %eax\n\t"
"jl 0f\n\t"
+ "cmpl " CMANGVAR(callMask) ", %eax\n\t"
+ "jae 1f\n\t"
"shll $2, %eax\n\t"
"addl " CMANGVAR(instructionPointers) ", %eax\n\t"
"call *(%eax)\n\t"
"movl (%edi), %eax\n\t"
- "andl " CMANGVAR(callMask) ", %eax\n\t"
"ret\n"
+ "1:\n\t" // bad address, leave something on the opstack
+ "call " CMANGFUNC(ErrJump) "\n\t"
+ //"addl $4, %edi\n\t"
+ //"movl $0, (%edi)\n\t"
+ //"ret\n\t"
"0:\n\t" // system call
"notl %eax\n\t"
"pushl %ebp\n\t"
@@ -249,6 +267,11 @@
return v;
}
+static int NextConstant4( void ) {
+ return (code[pc] | (code[pc+1]<<8) | (code[pc+2]<<16) | (code[pc+3]<<24));
+}
+
+
static int Constant1( void ) {
int v;
@@ -424,6 +447,7 @@
*/
void VM_Compile( vm_t *vm, vmHeader_t *header ) {
int op;
+ int op1;
int maxLength;
int v;
int i;
@@ -434,9 +458,17 @@
maxLength = header->codeLength * 8;
buf = Z_Malloc(maxLength);
jused = Z_Malloc(jusedSize);
+ code = Z_Malloc(header->codeLength+32);
Com_Memset(jused, 0, jusedSize);
+ Com_Memset(buf, 0, maxLength);
+ // copy code in larger buffer and put some zeros at the end
+ // so we can safely look ahead for a few instructions in it
+ // without a chance go get false-positive because of some garbage bytes
+ Com_Memset(code, 0, header->codeLength+32);
+ Com_Memcpy(code, (byte *)header + header->codeOffset, header->codeLength );
+
// ensure that the optimisation pass knows about all the jump
// table targets
for( i = 0; i < vm->numJumpTableTargets; i++ ) {
@@ -452,7 +484,7 @@
// translate all instructions
pc = 0;
instruction = 0;
- code = (byte *)header + header->codeOffset;
+ //code = (byte *)header + header->codeOffset;
compiledOfs = 0;
LastCommand = LAST_COMMAND_NONE;
@@ -487,7 +519,14 @@
Emit4( Constant4() );
break;
case OP_CONST:
- if (code[pc+4] == OP_LOAD4) {
+ // we can safely perform optimizations only in case if
+ // we are 100% sure that next instruction is not a jump label
+ if ( !jused[instruction] && vm->jumpTableTargets )
+ op1 = code[pc+4];
+ else
+ op1 = OP_UNDEF;
+
+ if ( op1 == OP_LOAD4 ) {
EmitAddEDI4(vm);
EmitString( "BB" ); // mov ebx, 0x12345678
Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
@@ -497,7 +536,7 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_LOAD2) {
+ if ( op1 == OP_LOAD2 ) {
EmitAddEDI4(vm);
EmitString( "BB" ); // mov ebx, 0x12345678
Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
@@ -507,7 +546,7 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_LOAD1) {
+ if ( op1 == OP_LOAD1 ) {
EmitAddEDI4(vm);
EmitString( "BB" ); // mov ebx, 0x12345678
Emit4( (Constant4()&vm->dataMask) + (int)vm->dataBase);
@@ -517,7 +556,7 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_STORE4) {
+ if ( op1 == OP_STORE4 ) {
opt = EmitMovEBXEDI(vm, (vm->dataMask & ~3));
EmitString( "B8" ); // mov eax, 0x12345678
Emit4( Constant4() );
@@ -532,7 +571,7 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_STORE2) {
+ if ( op1 == OP_STORE2 ) {
opt = EmitMovEBXEDI(vm, (vm->dataMask & ~1));
EmitString( "B8" ); // mov eax, 0x12345678
Emit4( Constant4() );
@@ -547,7 +586,7 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_STORE1) {
+ if ( op1 == OP_STORE1 ) {
opt = EmitMovEBXEDI(vm, vm->dataMask);
EmitString( "B8" ); // mov eax, 0x12345678
Emit4( Constant4() );
@@ -562,20 +601,117 @@
instruction += 1;
break;
}
- if (code[pc+4] == OP_ADD) {
+ if ( op1 == OP_ADD ) {
+ v = NextConstant4();
+ if ( v == 1 ) {
+ EmitString( "FF 07" ); // inc dword ptr [edi]
+ pc += 5; // OP_CONST + OP_ADD
+ instruction += 1;
+ break;
+ }
EmitString( "81 07" ); // add dword ptr [edi], 0x1234567
Emit4( Constant4() );
pc++; // OP_ADD
instruction += 1;
break;
}
- if (code[pc+4] == OP_SUB) {
+ if ( op1 == OP_SUB ) {
+ v = NextConstant4();
+ if ( v == 1 ) {
+ EmitString( "FF 0F" ); // dec dword ptr [edi]
+ pc += 5; // OP_CONST + OP_SUB
+ instruction += 1;
+ break;
+ }
EmitString( "81 2F" ); // sub dword ptr [edi], 0x1234567
Emit4( Constant4() );
pc++; // OP_ADD
instruction += 1;
break;
}
+ if ( op1 == OP_LSH ) {
+ v = NextConstant4();
+ if ( v >=1 && v <= 31 ) {
+ EmitString( "C1 27" ); // shl dword ptr [edi], 0x12
+ Emit1( v );
+ pc += 5; // OP_CONST + OP_LSH
+ instruction += 1;
+ break;
+ }
+ }
+ if ( op1 == OP_RSHI ) {
+ v = NextConstant4();
+ if ( v >=1 && v <= 31 ) {
+ EmitString( "C1 3F" ); // sar dword ptr [edi], 0x12
+ Emit1( v );
+ pc += 5; // OP_CONST + OP_RSHI
+ instruction += 1;
+ break;
+ }
+ }
+ if ( op1 == OP_RSHU ) {
+ v = NextConstant4();
+ if ( v >=1 && v <= 31 ) {
+ EmitString( "C1 2F" ); // shr dword ptr [edi], 0x12
+ Emit1( v );
+ pc += 5; // OP_CONST + OP_RSHU
+ instruction += 1;
+ break;
+ }
+ }
+ if ( op1 == OP_BAND ) {
+ v = NextConstant4();
+ // try to generate shorter version
+ if ( v >= 0 && v <= 127 ) {
+ EmitString( "83 27" ); // and dword ptr[edi], 0x7F
+ Emit1( v );
+ } else {
+ EmitString( "81 27" ); // and dword ptr[edi], 0x7FFFF
+ Emit4( v );
+ }
+ pc += 5; // OP_CONST + OP_BAND
+ instruction += 1;
+ break;
+ }
+ if ( op1 == OP_BOR ) {
+ v = NextConstant4();
+ // try to generate shorter version
+ if ( v >= 0 && v <= 127 ) {
+ EmitString( "83 0F" ); // or dword ptr[edi], 0x7F
+ Emit1( v );
+ } else {
+ EmitString( "81 0F" ); // or dword ptr[edi], 0x7FFFF
+ Emit4( v );
+ }
+ pc += 5; // OP_CONST + OP_BOR
+ instruction += 1;
+ break;
+ }
+ if ( op1 == OP_JUMP ) {
+ v = Constant4();
+ JUSED(v);
+ EmitString( "FF 25" ); // jmp dword ptr [instructionPointers + 0x12345678]
+ Emit4( (int)vm->instructionPointers + v*4 );
+ pc += 1; // OP_JUMP
+ instruction += 1;
+ break;
+ }
+
+ if ( op1 == OP_CALL && NextConstant4() >= 0 ) {
+ v = Constant4();
+ JUSED(v);
+ // FIXME: not needed?
+ //EmitString( "C7 86" ); // mov dword ptr [esi+database],0x12345678
+ //Emit4( (int)vm->dataBase );
+ //Emit4( pc );
+ EmitString( "FF 15" ); // call dword ptr [instructionPointers + 0x12345678]
+ Emit4( (int)vm->instructionPointers + v*4 );
+ EmitString( "8B 07" ); // mov eax, dword ptr [edi]
+ pc += 1; // OP_CALL
+ instruction += 1;
+ break;
+ }
+
EmitAddEDI4(vm);
EmitString( "C7 07" ); // mov dword ptr [edi], 0x12345678
lastConst = Constant4();
@@ -1076,11 +1212,15 @@
break;
case OP_JUMP:
- EmitCommand(LAST_COMMAND_SUB_DI_4); // sub edi, 4
- EmitString( "8B 47 04" ); // mov eax,dword ptr [edi+4]
- // FIXME: range check
- EmitString( "FF 24 85" ); // jmp dword ptr [instructionPointers + eax * 4]
+ EmitCommand(LAST_COMMAND_SUB_DI_4); // sub edi, 4
+ EmitString( "8B 47 04" ); // mov eax,dword ptr [edi+4]
+ EmitString( "3B 05" ); // cmp eax,[callMask]
+ Emit4( (int)&callMask );
+ EmitString( "73 07" ); // jae +7
+ EmitString( "FF 24 85" ); // jmp dword ptr [instructionPointers + eax * 4]
Emit4( (int)vm->instructionPointers );
+ EmitString( "FF 15" ); // call errJumpPtr
+ Emit4( (int)&errJumpPtr );
break;
default:
VMFREE_BUFFERS();
@@ -1123,6 +1263,7 @@
}
#endif
+ Z_Free( code );
Z_Free( buf );
Z_Free( jused );
Com_Printf( "VM file %s compiled to %i bytes of code\n", vm->name, compiledOfs );
@@ -1161,8 +1302,10 @@
byte *image;
void *opStack;
int *oldInstructionPointers;
+ int oldCallMask;
oldInstructionPointers = instructionPointers;
+ oldCallMask = callMask;
currentVM = vm;
instructionPointers = vm->instructionPointers;
@@ -1170,7 +1313,7 @@
// interpret the code
vm->currentlyInterpreting = qtrue;
- callMask = vm->dataMask;
+ callMask = vm->instructionCount;
// we might be called recursively, so this might not be the very top
programStack = vm->programStack;
@@ -1241,6 +1384,7 @@
// in case we were recursively called by another vm
instructionPointers = oldInstructionPointers;
+ callMask = oldCallMask;
return *(int *)opStack;
}