qzdoom-gpl/src/scripting/vm/vmexec.cpp
Christoph Oelckers b3783a3850 redid the exception mechanism for script-side access violations to be of more use for diagnosing problems.
The original implementation just printed a mostly information-free message and then went on as if nothing has happened, making it ridiculously easy to write broken code and release it. Changed it to:

* Any VMAbortException will now terminate the game session and go back to the console.
* It will also print a VM stack trace with all open functions, including source file and line numbers pointing to the problem spots. For this the relevant information had to be added to the VMScriptFunction class.

An interesting effect here was that just throwing the exception object increased the VM's Exec function's stack size from 900 bytes to 70kb, because the compiler allocates a separate local buffer for every single instance of the exception object.
The obvious solution was to put this part into a subfunction so that it won't pollute the Exec function's own stack frame. Interesting side effect of this: Exec's stack requirement went down from 900 bytes to 600 bytes. This is still on the high side but already a lot better.
2016-12-03 12:23:13 +01:00

235 lines
6.5 KiB
C++

/*
** vmexec.cpp
**
**---------------------------------------------------------------------------
** Copyright -2016 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in the
** documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
** derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/
#include <math.h>
#include <v_video.h>
#include <s_sound.h>
#include "dobject.h"
#include "xs_Float.h"
#include "r_state.h"
#include "textures/textures.h"
#include "math/cmath.h"
// This must be a separate function because the VC compiler would otherwise allocate memory on the stack for every separate instance of the exception object that may get thrown.
void ThrowAbortException(EVMAbortException reason, const char *moreinfo, ...);
// intentionally implemented in a different source file tp prevent inlining.
void ThrowVMException(VMException *x);
#define IMPLEMENT_VMEXEC
#if !defined(COMPGOTO) && defined(__GNUC__)
#define COMPGOTO 1
#endif
#if COMPGOTO
#define OP(x) x
#define NEXTOP do { pc++; unsigned op = pc->op; a = pc->a; goto *ops[op]; } while(0)
#else
#define OP(x) case OP_##x
#define NEXTOP pc++; break
#endif
#define luai_nummod(a,b) ((a) - floor((a)/(b))*(b))
#define A (pc[0].a)
#define B (pc[0].b)
#define C (pc[0].c)
#define Cs (pc[0].cs)
#define BC (pc[0].i16u)
#define BCs (pc[0].i16)
#define ABCs (pc[0].i24)
#define JMPOFS(x) ((x)->i24)
#define KC (konstd[C])
#define RC (reg.d[C])
#define PA (reg.a[A])
#define PB (reg.a[B])
#define ASSERTD(x) assert((unsigned)(x) < f->NumRegD)
#define ASSERTF(x) assert((unsigned)(x) < f->NumRegF)
#define ASSERTA(x) assert((unsigned)(x) < f->NumRegA)
#define ASSERTS(x) assert((unsigned)(x) < f->NumRegS)
#define ASSERTO(x) assert((unsigned)(x) < f->NumRegA && reg.atag[x] == ATAG_OBJECT)
#define ASSERTKD(x) assert(sfunc != NULL && (unsigned)(x) < sfunc->NumKonstD)
#define ASSERTKF(x) assert(sfunc != NULL && (unsigned)(x) < sfunc->NumKonstF)
#define ASSERTKA(x) assert(sfunc != NULL && (unsigned)(x) < sfunc->NumKonstA)
#define ASSERTKS(x) assert(sfunc != NULL && (unsigned)(x) < sfunc->NumKonstS)
#define CMPJMP(test) \
if ((test) == (a & CMP_CHECK)) { \
assert(pc[1].op == OP_JMP); \
pc += 1 + JMPOFS(pc+1); \
} else { \
pc += 1; \
}
#define GETADDR(a,o,x) \
if (a == NULL) { ThrowAbortException(x, nullptr); } \
ptr = (VM_SBYTE *)a + o
static const VM_UWORD ZapTable[16] =
{
0x00000000, 0x000000FF, 0x0000FF00, 0x0000FFFF,
0x00FF0000, 0x00FF00FF, 0x00FFFF00, 0x00FFFFFF,
0xFF000000, 0xFF0000FF, 0xFF00FF00, 0xFF00FFFF,
0xFFFF0000, 0xFFFF00FF, 0xFFFFFF00, 0xFFFFFFFF
};
#ifdef NDEBUG
#define WAS_NDEBUG 1
#else
#define WAS_NDEBUG 0
#endif
#if WAS_NDEBUG
#undef NDEBUG
#endif
#undef assert
#include <assert.h>
struct VMExec_Checked
{
#include "vmexec.h"
};
#if WAS_NDEBUG
#define NDEBUG
#endif
#if !WAS_NDEBUG
#define NDEBUG
#endif
#undef assert
#include <assert.h>
struct VMExec_Unchecked
{
#include "vmexec.h"
};
#if !WAS_NDEBUG
#undef NDEBUG
#endif
#undef assert
#include <assert.h>
int (*VMExec)(VMFrameStack *stack, const VMOP *pc, VMReturn *ret, int numret) =
#ifdef NDEBUG
VMExec_Unchecked::Exec
#else
VMExec_Checked::Exec
#endif
;
// Note: If the VM is being used in multiple threads, this should be declared as thread_local.
// ZDoom doesn't need this at the moment so this is disabled.
thread_local VMFrameStack GlobalVMStack;
//===========================================================================
//
// VMSelectEngine
//
// Selects the VM engine, either checked or unchecked. Default will decide
// based on the NDEBUG preprocessor definition.
//
//===========================================================================
void VMSelectEngine(EVMEngine engine)
{
switch (engine)
{
case VMEngine_Default:
#ifdef NDEBUG
VMExec = VMExec_Unchecked::Exec;
#else
#endif
VMExec = VMExec_Checked::Exec;
break;
case VMEngine_Unchecked:
VMExec = VMExec_Unchecked::Exec;
break;
case VMEngine_Checked:
VMExec = VMExec_Checked::Exec;
break;
}
}
//===========================================================================
//
// VMFillParams
//
// Takes parameters from the parameter stack and stores them in the callee's
// registers.
//
//===========================================================================
void VMFillParams(VMValue *params, VMFrame *callee, int numparam)
{
unsigned int regd, regf, regs, rega;
VMScriptFunction *calleefunc = static_cast<VMScriptFunction *>(callee->Func);
const VMRegisters calleereg(callee);
assert(calleefunc != NULL && !calleefunc->Native);
assert(numparam == calleefunc->NumArgs || ((int)calleefunc->DefaultArgs.Size() == calleefunc->NumArgs));
assert(REGT_INT == 0 && REGT_FLOAT == 1 && REGT_STRING == 2 && REGT_POINTER == 3);
regd = regf = regs = rega = 0;
for (int i = 0; i < calleefunc->NumArgs; ++i)
{
// get all actual parameters and fill the rest from the defaults.
VMValue &p = i < numparam? params[i] : calleefunc->DefaultArgs[i];
if (p.Type < REGT_STRING)
{
if (p.Type == REGT_INT)
{
calleereg.d[regd++] = p.i;
}
else // p.Type == REGT_FLOAT
{
calleereg.f[regf++] = p.f;
}
}
else if (p.Type == REGT_STRING)
{
calleereg.s[regs++] = p.s();
}
else
{
assert(p.Type == REGT_POINTER);
calleereg.a[rega] = p.a;
calleereg.atag[rega++] = p.atag;
}
}
}