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gcc/libjava/verify.cc
Tom Tromey 6d8b12448d resolve.cc (_Jv_PrepareClass): Verify method here... 
* resolve.cc (_Jv_PrepareClass): Verify method here...
	* defineclass.cc (handleMethodsEnd): ... not here.
	* verify.cc (_Jv_BytecodeVerifier::initialize_stack): New method.
	(_Jv_BytecodeVerifier::verify_instructions_0) [op_return]: Ensure
	there are no uninitialized objects.
	(_Jv_BytecodeVerifier::state::this_type): New field.
	(_Jv_BytecodeVerifier::state::state): Initialize this_type.
	(_Jv_BytecodeVerifier::state::copy): Copy this_type.
	(_Jv_BytecodeVerifier::state::merge): Merge this_type.
	(_Jv_BytecodeVerifier::state::check_no_uninitialized_objects):
	Handle this_type.
	(_Jv_BytecodeVerifier::state::check_this_initialized): New
	method.
	(_Jv_BytecodeVerifier::state::set_initialized): Handle this_type.
	(_Jv_BytecodeVerifier::state::set_this_type): New method.
	(_Jv_BytecodeVerifier::verify_instructions_0) [op_putfield]: Allow
	assignment to fields of `this' before another initializer is run.

From-SVN: r47826
2001-12-10 01:18:30 +00:00

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// defineclass.cc - defining a class from .class format.
/* Copyright (C) 2001 Free Software Foundation
This file is part of libgcj.
This software is copyrighted work licensed under the terms of the
Libgcj License. Please consult the file "LIBGCJ_LICENSE" for
details. */
// Written by Tom Tromey <tromey@redhat.com>
// Define VERIFY_DEBUG to enable debugging output.
#include <config.h>
#include <jvm.h>
#include <gcj/cni.h>
#include <java-insns.h>
#include <java-interp.h>
#ifdef INTERPRETER
#include <java/lang/Class.h>
#include <java/lang/VerifyError.h>
#include <java/lang/Throwable.h>
#include <java/lang/reflect/Modifier.h>
#include <java/lang/StringBuffer.h>
#ifdef VERIFY_DEBUG
#include <stdio.h>
#endif /* VERIFY_DEBUG */
// TO DO
// * read more about when classes must be loaded
// * class loader madness
// * Lots and lots of debugging and testing
// * type representation is still ugly. look for the big switches
// * at least one GC problem :-(
// This is global because __attribute__ doesn't seem to work on static
// methods.
static void verify_fail (char *msg, jint pc = -1)
__attribute__ ((__noreturn__));
static void debug_print (const char *fmt, ...)
__attribute__ ((format (printf, 1, 2)));
static inline void
debug_print (const char *fmt, ...)
{
#ifdef VERIFY_DEBUG
va_list ap;
va_start (ap, fmt);
vfprintf (stderr, fmt, ap);
va_end (ap);
#endif /* VERIFY_DEBUG */
}
class _Jv_BytecodeVerifier
{
private:
static const int FLAG_INSN_START = 1;
static const int FLAG_BRANCH_TARGET = 2;
struct state;
struct type;
struct subr_info;
struct linked_utf8;
// The current PC.
int PC;
// The PC corresponding to the start of the current instruction.
int start_PC;
// The current state of the stack, locals, etc.
state *current_state;
// We store the state at branch targets, for merging. This holds
// such states.
state **states;
// We keep a linked list of all the PCs which we must reverify.
// The link is done using the PC values. This is the head of the
// list.
int next_verify_pc;
// We keep some flags for each instruction. The values are the
// FLAG_* constants defined above.
char *flags;
// We need to keep track of which instructions can call a given
// subroutine. FIXME: this is inefficient. We keep a linked list
// of all calling `jsr's at at each jsr target.
subr_info **jsr_ptrs;
// The current top of the stack, in terms of slots.
int stacktop;
// The current depth of the stack. This will be larger than
// STACKTOP when wide types are on the stack.
int stackdepth;
// The bytecode itself.
unsigned char *bytecode;
// The exceptions.
_Jv_InterpException *exception;
// Defining class.
jclass current_class;
// This method.
_Jv_InterpMethod *current_method;
// A linked list of utf8 objects we allocate. This is really ugly,
// but without this our utf8 objects would be collected.
linked_utf8 *utf8_list;
struct linked_utf8
{
_Jv_Utf8Const *val;
linked_utf8 *next;
};
_Jv_Utf8Const *make_utf8_const (char *s, int len)
{
_Jv_Utf8Const *val = _Jv_makeUtf8Const (s, len);
_Jv_Utf8Const *r = (_Jv_Utf8Const *) _Jv_Malloc (sizeof (_Jv_Utf8Const)
+ val->length
+ 1);
r->length = val->length;
r->hash = val->hash;
memcpy (r->data, val->data, val->length + 1);
linked_utf8 *lu = (linked_utf8 *) _Jv_Malloc (sizeof (linked_utf8));
lu->val = r;
lu->next = utf8_list;
utf8_list = lu;
return r;
}
// This enum holds a list of tags for all the different types we
// need to handle. Reference types are treated specially by the
// type class.
enum type_val
{
void_type,
// The values for primitive types are chosen to correspond to values
// specified to newarray.
boolean_type = 4,
char_type = 5,
float_type = 6,
double_type = 7,
byte_type = 8,
short_type = 9,
int_type = 10,
long_type = 11,
// Used when overwriting second word of a double or long in the
// local variables. Also used after merging local variable states
// to indicate an unusable value.
unsuitable_type,
return_address_type,
continuation_type,
// There is an obscure special case which requires us to note when
// a local variable has not been used by a subroutine. See
// push_jump_merge for more information.
unused_by_subroutine_type,
// Everything after `reference_type' must be a reference type.
reference_type,
null_type,
unresolved_reference_type,
uninitialized_reference_type,
uninitialized_unresolved_reference_type
};
// Return the type_val corresponding to a primitive signature
// character. For instance `I' returns `int.class'.
static type_val get_type_val_for_signature (jchar sig)
{
type_val rt;
switch (sig)
{
case 'Z':
rt = boolean_type;
break;
case 'B':
rt = byte_type;
break;
case 'C':
rt = char_type;
break;
case 'S':
rt = short_type;
break;
case 'I':
rt = int_type;
break;
case 'J':
rt = long_type;
break;
case 'F':
rt = float_type;
break;
case 'D':
rt = double_type;
break;
case 'V':
rt = void_type;
break;
default:
verify_fail ("invalid signature");
}
return rt;
}
// Return the type_val corresponding to a primitive class.
static type_val get_type_val_for_signature (jclass k)
{
return get_type_val_for_signature ((jchar) k->method_count);
}
// This is like _Jv_IsAssignableFrom, but it works even if SOURCE or
// TARGET haven't been prepared.
static bool is_assignable_from_slow (jclass target, jclass source)
{
// This will terminate when SOURCE==Object.
while (true)
{
if (source == target)
return true;
if (target->isPrimitive () || source->isPrimitive ())
return false;
// Check array case first because we can have an array whose
// component type is not prepared; _Jv_IsAssignableFrom
// doesn't handle this correctly.
if (target->isArray ())
{
if (! source->isArray ())
return false;
target = target->getComponentType ();
source = source->getComponentType ();
}
// _Jv_IsAssignableFrom can handle a target which is an
// interface even if it hasn't been prepared.
else if ((target->state > JV_STATE_LINKED || target->isInterface ())
&& source->state > JV_STATE_LINKED)
return _Jv_IsAssignableFrom (target, source);
else if (target->isInterface ())
{
for (int i = 0; i < source->interface_count; ++i)
{
// We use a recursive call because we also need to
// check superinterfaces.
if (is_assignable_from_slow (target, source->interfaces[i]))
return true;
}
return false;
}
else if (target == &java::lang::Object::class$)
return true;
else if (source->isInterface ()
|| source == &java::lang::Object::class$)
return false;
else
source = source->getSuperclass ();
}
}
// This is used to keep track of which `jsr's correspond to a given
// jsr target.
struct subr_info
{
// PC of the instruction just after the jsr.
int pc;
// Link.
subr_info *next;
};
// The `type' class is used to represent a single type in the
// verifier.
struct type
{
// The type.
type_val key;
// Some associated data.
union
{
// For a resolved reference type, this is a pointer to the class.
jclass klass;
// For other reference types, this it the name of the class.
_Jv_Utf8Const *name;
} data;
// This is used when constructing a new object. It is the PC of the
// `new' instruction which created the object. We use the special
// value -2 to mean that this is uninitialized, and the special
// value -1 for the case where the current method is itself the
// <init> method.
int pc;
static const int UNINIT = -2;
static const int SELF = -1;
// Basic constructor.
type ()
{
key = unsuitable_type;
data.klass = NULL;
pc = UNINIT;
}
// Make a new instance given the type tag. We assume a generic
// `reference_type' means Object.
type (type_val k)
{
key = k;
data.klass = NULL;
if (key == reference_type)
data.klass = &java::lang::Object::class$;
pc = UNINIT;
}
// Make a new instance given a class.
type (jclass klass)
{
key = reference_type;
data.klass = klass;
pc = UNINIT;
}
// Make a new instance given the name of a class.
type (_Jv_Utf8Const *n)
{
key = unresolved_reference_type;
data.name = n;
pc = UNINIT;
}
// Copy constructor.
type (const type &t)
{
key = t.key;
data = t.data;
pc = t.pc;
}
// These operators are required because libgcj can't link in
// -lstdc++.
void *operator new[] (size_t bytes)
{
return _Jv_Malloc (bytes);
}
void operator delete[] (void *mem)
{
_Jv_Free (mem);
}
type& operator= (type_val k)
{
key = k;
data.klass = NULL;
pc = UNINIT;
return *this;
}
type& operator= (const type& t)
{
key = t.key;
data = t.data;
pc = t.pc;
return *this;
}
// Promote a numeric type.
type &promote ()
{
if (key == boolean_type || key == char_type
|| key == byte_type || key == short_type)
key = int_type;
return *this;
}
// If *THIS is an unresolved reference type, resolve it.
void resolve ()
{
if (key != unresolved_reference_type
&& key != uninitialized_unresolved_reference_type)
return;
// FIXME: class loader
using namespace java::lang;
// We might see either kind of name. Sigh.
if (data.name->data[0] == 'L'
&& data.name->data[data.name->length - 1] == ';')
data.klass = _Jv_FindClassFromSignature (data.name->data, NULL);
else
data.klass = Class::forName (_Jv_NewStringUtf8Const (data.name),
false, NULL);
key = (key == unresolved_reference_type
? reference_type
: uninitialized_reference_type);
}
// Mark this type as the uninitialized result of `new'.
void set_uninitialized (int npc)
{
if (key == reference_type)
key = uninitialized_reference_type;
else if (key == unresolved_reference_type)
key = uninitialized_unresolved_reference_type;
else
verify_fail ("internal error in type::uninitialized");
pc = npc;
}
// Mark this type as now initialized.
void set_initialized (int npc)
{
if (npc != UNINIT && pc == npc
&& (key == uninitialized_reference_type
|| key == uninitialized_unresolved_reference_type))
{
key = (key == uninitialized_reference_type
? reference_type
: unresolved_reference_type);
pc = UNINIT;
}
}
// Return true if an object of type K can be assigned to a variable
// of type *THIS. Handle various special cases too. Might modify
// *THIS or K. Note however that this does not perform numeric
// promotion.
bool compatible (type &k)
{
// Any type is compatible with the unsuitable type.
if (key == unsuitable_type)
return true;
if (key < reference_type || k.key < reference_type)
return key == k.key;
// The `null' type is convertible to any reference type.
// FIXME: is this correct for THIS?
if (key == null_type || k.key == null_type)
return true;
// Any reference type is convertible to Object. This is a special
// case so we don't need to unnecessarily resolve a class.
if (key == reference_type
&& data.klass == &java::lang::Object::class$)
return true;
// An initialized type and an uninitialized type are not
// compatible.
if (isinitialized () != k.isinitialized ())
return false;
// Two uninitialized objects are compatible if either:
// * The PCs are identical, or
// * One PC is UNINIT.
if (! isinitialized ())
{
if (pc != k.pc && pc != UNINIT && k.pc != UNINIT)
return false;
}
// Two unresolved types are equal if their names are the same.
if (! isresolved ()
&& ! k.isresolved ()
&& _Jv_equalUtf8Consts (data.name, k.data.name))
return true;
// We must resolve both types and check assignability.
resolve ();
k.resolve ();
return is_assignable_from_slow (data.klass, k.data.klass);
}
bool isvoid () const
{
return key == void_type;
}
bool iswide () const
{
return key == long_type || key == double_type;
}
// Return number of stack or local variable slots taken by this
// type.
int depth () const
{
return iswide () ? 2 : 1;
}
bool isarray () const
{
// We treat null_type as not an array. This is ok based on the
// current uses of this method.
if (key == reference_type)
return data.klass->isArray ();
else if (key == unresolved_reference_type)
return data.name->data[0] == '[';
return false;
}
bool isinterface ()
{
resolve ();
if (key != reference_type)
return false;
return data.klass->isInterface ();
}
bool isabstract ()
{
resolve ();
if (key != reference_type)
return false;
using namespace java::lang::reflect;
return Modifier::isAbstract (data.klass->getModifiers ());
}
// Return the element type of an array.
type element_type ()
{
// FIXME: maybe should do string manipulation here.
resolve ();
if (key != reference_type)
verify_fail ("programmer error in type::element_type()");
jclass k = data.klass->getComponentType ();
if (k->isPrimitive ())
return type (get_type_val_for_signature (k));
return type (k);
}
// Return the array type corresponding to an initialized
// reference. We could expand this to work for other kinds of
// types, but currently we don't need to.
type to_array ()
{
// Resolving isn't ideal, because it might force us to load
// another class, but it's easy. FIXME?
if (key == unresolved_reference_type)
resolve ();
if (key == reference_type)
return type (_Jv_GetArrayClass (data.klass,
data.klass->getClassLoader ()));
else
verify_fail ("internal error in type::to_array()");
}
bool isreference () const
{
return key >= reference_type;
}
int get_pc () const
{
return pc;
}
bool isinitialized () const
{
return (key == reference_type
|| key == null_type
|| key == unresolved_reference_type);
}
bool isresolved () const
{
return (key == reference_type
|| key == null_type
|| key == uninitialized_reference_type);
}
void verify_dimensions (int ndims)
{
// The way this is written, we don't need to check isarray().
if (key == reference_type)
{
jclass k = data.klass;
while (k->isArray () && ndims > 0)
{
k = k->getComponentType ();
--ndims;
}
}
else
{
// We know KEY == unresolved_reference_type.
char *p = data.name->data;
while (*p++ == '[' && ndims-- > 0)
;
}
if (ndims > 0)
verify_fail ("array type has fewer dimensions than required");
}
// Merge OLD_TYPE into this. On error throw exception.
bool merge (type& old_type, bool local_semantics = false)
{
bool changed = false;
bool refo = old_type.isreference ();
bool refn = isreference ();
if (refo && refn)
{
if (old_type.key == null_type)
;
else if (key == null_type)
{
*this = old_type;
changed = true;
}
else if (isinitialized () != old_type.isinitialized ())
verify_fail ("merging initialized and uninitialized types");
else
{
if (! isinitialized ())
{
if (pc == UNINIT)
pc = old_type.pc;
else if (old_type.pc == UNINIT)
;
else if (pc != old_type.pc)
verify_fail ("merging different uninitialized types");
}
if (! isresolved ()
&& ! old_type.isresolved ()
&& _Jv_equalUtf8Consts (data.name, old_type.data.name))
{
// Types are identical.
}
else
{
resolve ();
old_type.resolve ();
jclass k = data.klass;
jclass oldk = old_type.data.klass;
int arraycount = 0;
while (k->isArray () && oldk->isArray ())
{
++arraycount;
k = k->getComponentType ();
oldk = oldk->getComponentType ();
}
// This loop will end when we hit Object.
while (true)
{
if (is_assignable_from_slow (k, oldk))
break;
k = k->getSuperclass ();
changed = true;
}
if (changed)
{
while (arraycount > 0)
{
// FIXME: Class loader.
k = _Jv_GetArrayClass (k, NULL);
--arraycount;
}
data.klass = k;
}
}
}
}
else if (refo || refn || key != old_type.key)
{
if (local_semantics)
{
// If we're merging into an "unused" slot, then we
// simply accept whatever we're merging from.
if (key == unused_by_subroutine_type)
{
*this = old_type;
changed = true;
}
else if (old_type.key == unused_by_subroutine_type)
{
// Do nothing.
}
// If we already have an `unsuitable' type, then we
// don't need to change again.
else if (key != unsuitable_type)
{
key = unsuitable_type;
changed = true;
}
}
else
verify_fail ("unmergeable type");
}
return changed;
}
#ifdef VERIFY_DEBUG
void print (void) const
{
char c = '?';
switch (key)
{
case boolean_type: c = 'Z'; break;
case byte_type: c = 'B'; break;
case char_type: c = 'C'; break;
case short_type: c = 'S'; break;
case int_type: c = 'I'; break;
case long_type: c = 'J'; break;
case float_type: c = 'F'; break;
case double_type: c = 'D'; break;
case void_type: c = 'V'; break;
case unsuitable_type: c = '-'; break;
case return_address_type: c = 'r'; break;
case continuation_type: c = '+'; break;
case unused_by_subroutine_type: c = '_'; break;
case reference_type: c = 'L'; break;
case null_type: c = '@'; break;
case unresolved_reference_type: c = 'l'; break;
case uninitialized_reference_type: c = 'U'; break;
case uninitialized_unresolved_reference_type: c = 'u'; break;
}
debug_print ("%c", c);
}
#endif /* VERIFY_DEBUG */
};
// This class holds all the state information we need for a given
// location.
struct state
{
// Current top of stack.
int stacktop;
// Current stack depth. This is like the top of stack but it
// includes wide variable information.
int stackdepth;
// The stack.
type *stack;
// The local variables.
type *locals;
// This is used in subroutines to keep track of which local
// variables have been accessed.
bool *local_changed;
// If not 0, then we are in a subroutine. The value is the PC of
// the subroutine's entry point. We can use 0 as an exceptional
// value because PC=0 can never be a subroutine.
int subroutine;
// This is used to keep a linked list of all the states which
// require re-verification. We use the PC to keep track.
int next;
// We keep track of the type of `this' specially. This is used to
// ensure that an instance initializer invokes another initializer
// on `this' before returning. We must keep track of this
// specially because otherwise we might be confused by code which
// assigns to locals[0] (overwriting `this') and then returns
// without really initializing.
type this_type;
// INVALID marks a state which is not on the linked list of states
// requiring reverification.
static const int INVALID = -1;
// NO_NEXT marks the state at the end of the reverification list.
static const int NO_NEXT = -2;
state ()
: this_type ()
{
stack = NULL;
locals = NULL;
local_changed = NULL;
}
state (int max_stack, int max_locals)
: this_type ()
{
stacktop = 0;
stackdepth = 0;
stack = new type[max_stack];
for (int i = 0; i < max_stack; ++i)
stack[i] = unsuitable_type;
locals = new type[max_locals];
local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
for (int i = 0; i < max_locals; ++i)
{
locals[i] = unsuitable_type;
local_changed[i] = false;
}
next = INVALID;
subroutine = 0;
}
state (const state *orig, int max_stack, int max_locals,
bool ret_semantics = false)
{
stack = new type[max_stack];
locals = new type[max_locals];
local_changed = (bool *) _Jv_Malloc (sizeof (bool) * max_locals);
copy (orig, max_stack, max_locals, ret_semantics);
next = INVALID;
}
~state ()
{
if (stack)
delete[] stack;
if (locals)
delete[] locals;
if (local_changed)
_Jv_Free (local_changed);
}
void *operator new[] (size_t bytes)
{
return _Jv_Malloc (bytes);
}
void operator delete[] (void *mem)
{
_Jv_Free (mem);
}
void *operator new (size_t bytes)
{
return _Jv_Malloc (bytes);
}
void operator delete (void *mem)
{
_Jv_Free (mem);
}
void copy (const state *copy, int max_stack, int max_locals,
bool ret_semantics = false)
{
stacktop = copy->stacktop;
stackdepth = copy->stackdepth;
subroutine = copy->subroutine;
for (int i = 0; i < max_stack; ++i)
stack[i] = copy->stack[i];
for (int i = 0; i < max_locals; ++i)
{
// See push_jump_merge to understand this case.
if (ret_semantics)
locals[i] = type (copy->local_changed[i]
? unsuitable_type
: unused_by_subroutine_type);
else
locals[i] = copy->locals[i];
local_changed[i] = copy->local_changed[i];
}
this_type = copy->this_type;
// Don't modify `next'.
}
// Modify this state to reflect entry to an exception handler.
void set_exception (type t, int max_stack)
{
stackdepth = 1;
stacktop = 1;
stack[0] = t;
for (int i = stacktop; i < max_stack; ++i)
stack[i] = unsuitable_type;
// FIXME: subroutine handling?
}
// Merge STATE_OLD into this state. Destructively modifies this
// state. Returns true if the new state was in fact changed.
// Will throw an exception if the states are not mergeable.
bool merge (state *state_old, bool ret_semantics,
int max_locals)
{
bool changed = false;
// Special handling for `this'. If one or the other is
// uninitialized, then the merge is uninitialized.
if (this_type.isinitialized ())
this_type = state_old->this_type;
// Merge subroutine states. *THIS and *STATE_OLD must be in the
// same subroutine. Also, recursive subroutine calls must be
// avoided.
if (subroutine == state_old->subroutine)
{
// Nothing.
}
else if (subroutine == 0)
{
subroutine = state_old->subroutine;
changed = true;
}
else
verify_fail ("subroutines merged");
// Merge stacks.
if (state_old->stacktop != stacktop)
verify_fail ("stack sizes differ");
for (int i = 0; i < state_old->stacktop; ++i)
{
if (stack[i].merge (state_old->stack[i]))
changed = true;
}
// Merge local variables.
for (int i = 0; i < max_locals; ++i)
{
if (! ret_semantics || local_changed[i])
{
if (locals[i].merge (state_old->locals[i], true))
{
changed = true;
note_variable (i);
}
}
// If we're in a subroutine, we must compute the union of
// all the changed local variables.
if (state_old->local_changed[i])
note_variable (i);
}
return changed;
}
// Throw an exception if there is an uninitialized object on the
// stack or in a local variable. EXCEPTION_SEMANTICS controls
// whether we're using backwards-branch or exception-handing
// semantics.
void check_no_uninitialized_objects (int max_locals,
bool exception_semantics = false)
{
if (! exception_semantics)
{
for (int i = 0; i < stacktop; ++i)
if (stack[i].isreference () && ! stack[i].isinitialized ())
verify_fail ("uninitialized object on stack");
}
for (int i = 0; i < max_locals; ++i)
if (locals[i].isreference () && ! locals[i].isinitialized ())
verify_fail ("uninitialized object in local variable");
check_this_initialized ();
}
// Ensure that `this' has been initialized.
void check_this_initialized ()
{
if (this_type.isreference () && ! this_type.isinitialized ())
verify_fail ("`this' is uninitialized");
}
// Set type of `this'.
void set_this_type (const type &k)
{
this_type = k;
}
// Note that a local variable was modified.
void note_variable (int index)
{
if (subroutine > 0)
local_changed[index] = true;
}
// Mark each `new'd object we know of that was allocated at PC as
// initialized.
void set_initialized (int pc, int max_locals)
{
for (int i = 0; i < stacktop; ++i)
stack[i].set_initialized (pc);
for (int i = 0; i < max_locals; ++i)
locals[i].set_initialized (pc);
this_type.set_initialized (pc);
}
// Return true if this state is the unmerged result of a `ret'.
bool is_unmerged_ret_state (int max_locals) const
{
for (int i = 0; i < max_locals; ++i)
{
if (locals[i].key == unused_by_subroutine_type)
return true;
}
return false;
}
#ifdef VERIFY_DEBUG
void print (const char *leader, int pc,
int max_stack, int max_locals) const
{
debug_print ("%s [%4d]: [stack] ", leader, pc);
int i;
for (i = 0; i < stacktop; ++i)
stack[i].print ();
for (; i < max_stack; ++i)
debug_print (".");
debug_print (" [local] ");
for (i = 0; i < max_locals; ++i)
locals[i].print ();
debug_print (" | %p\n", this);
}
#else
inline void print (const char *, int, int, int) const
{
}
#endif /* VERIFY_DEBUG */
};
type pop_raw ()
{
if (current_state->stacktop <= 0)
verify_fail ("stack empty", start_PC);
type r = current_state->stack[--current_state->stacktop];
current_state->stackdepth -= r.depth ();
if (current_state->stackdepth < 0)
verify_fail ("stack empty", start_PC);
return r;
}
type pop32 ()
{
type r = pop_raw ();
if (r.iswide ())
verify_fail ("narrow pop of wide type", start_PC);
return r;
}
type pop64 ()
{
type r = pop_raw ();
if (! r.iswide ())
verify_fail ("wide pop of narrow type", start_PC);
return r;
}
type pop_type (type match)
{
match.promote ();
type t = pop_raw ();
if (! match.compatible (t))
verify_fail ("incompatible type on stack", start_PC);
return t;
}
// Pop a reference type or a return address.
type pop_ref_or_return ()
{
type t = pop_raw ();
if (! t.isreference () && t.key != return_address_type)
verify_fail ("expected reference or return address on stack", start_PC);
return t;
}
void push_type (type t)
{
// If T is a numeric type like short, promote it to int.
t.promote ();
int depth = t.depth ();
if (current_state->stackdepth + depth > current_method->max_stack)
verify_fail ("stack overflow");
current_state->stack[current_state->stacktop++] = t;
current_state->stackdepth += depth;
}
void set_variable (int index, type t)
{
// If T is a numeric type like short, promote it to int.
t.promote ();
int depth = t.depth ();
if (index > current_method->max_locals - depth)
verify_fail ("invalid local variable");
current_state->locals[index] = t;
current_state->note_variable (index);
if (depth == 2)
{
current_state->locals[index + 1] = continuation_type;
current_state->note_variable (index + 1);
}
if (index > 0 && current_state->locals[index - 1].iswide ())
{
current_state->locals[index - 1] = unsuitable_type;
// There's no need to call note_variable here.
}
}
type get_variable (int index, type t)
{
int depth = t.depth ();
if (index > current_method->max_locals - depth)
verify_fail ("invalid local variable", start_PC);
if (! t.compatible (current_state->locals[index]))
verify_fail ("incompatible type in local variable", start_PC);
if (depth == 2)
{
type t (continuation_type);
if (! current_state->locals[index + 1].compatible (t))
verify_fail ("invalid local variable", start_PC);
}
return current_state->locals[index];
}
// Make sure ARRAY is an array type and that its elements are
// compatible with type ELEMENT. Returns the actual element type.
type require_array_type (type array, type element)
{
if (! array.isarray ())
verify_fail ("array required");
type t = array.element_type ();
if (! element.compatible (t))
{
// Special case for byte arrays, which must also be boolean
// arrays.
bool ok = true;
if (element.key == byte_type)
{
type e2 (boolean_type);
ok = e2.compatible (t);
}
if (! ok)
verify_fail ("incompatible array element type");
}
// Return T and not ELEMENT, because T might be specialized.
return t;
}
jint get_byte ()
{
if (PC >= current_method->code_length)
verify_fail ("premature end of bytecode");
return (jint) bytecode[PC++] & 0xff;
}
jint get_ushort ()
{
jint b1 = get_byte ();
jint b2 = get_byte ();
return (jint) ((b1 << 8) | b2) & 0xffff;
}
jint get_short ()
{
jint b1 = get_byte ();
jint b2 = get_byte ();
jshort s = (b1 << 8) | b2;
return (jint) s;
}
jint get_int ()
{
jint b1 = get_byte ();
jint b2 = get_byte ();
jint b3 = get_byte ();
jint b4 = get_byte ();
return (b1 << 24) | (b2 << 16) | (b3 << 8) | b4;
}
int compute_jump (int offset)
{
int npc = start_PC + offset;
if (npc < 0 || npc >= current_method->code_length)
verify_fail ("branch out of range", start_PC);
return npc;
}
// Merge the indicated state into the state at the branch target and
// schedule a new PC if there is a change. If RET_SEMANTICS is
// true, then we are merging from a `ret' instruction into the
// instruction after a `jsr'. This is a special case with its own
// modified semantics.
void push_jump_merge (int npc, state *nstate, bool ret_semantics = false)
{
bool changed = true;
if (states[npc] == NULL)
{
// There's a weird situation here. If are examining the
// branch that results from a `ret', and there is not yet a
// state available at the branch target (the instruction just
// after the `jsr'), then we have to construct a special kind
// of state at that point for future merging. This special
// state has the type `unused_by_subroutine_type' in each slot
// which was not modified by the subroutine.
states[npc] = new state (nstate, current_method->max_stack,
current_method->max_locals, ret_semantics);
debug_print ("== New state in push_jump_merge\n");
states[npc]->print ("New", npc, current_method->max_stack,
current_method->max_locals);
}
else
{
debug_print ("== Merge states in push_jump_merge\n");
nstate->print ("Frm", start_PC, current_method->max_stack,
current_method->max_locals);
states[npc]->print (" To", npc, current_method->max_stack,
current_method->max_locals);
changed = states[npc]->merge (nstate, ret_semantics,
current_method->max_locals);
states[npc]->print ("New", npc, current_method->max_stack,
current_method->max_locals);
}
if (changed && states[npc]->next == state::INVALID)
{
// The merge changed the state, and the new PC isn't yet on our
// list of PCs to re-verify.
states[npc]->next = next_verify_pc;
next_verify_pc = npc;
}
}
void push_jump (int offset)
{
int npc = compute_jump (offset);
if (npc < PC)
current_state->check_no_uninitialized_objects (current_method->max_locals);
push_jump_merge (npc, current_state);
}
void push_exception_jump (type t, int pc)
{
current_state->check_no_uninitialized_objects (current_method->max_locals,
true);
state s (current_state, current_method->max_stack,
current_method->max_locals);
s.set_exception (t, current_method->max_stack);
push_jump_merge (pc, &s);
}
int pop_jump ()
{
int *prev_loc = &next_verify_pc;
int npc = next_verify_pc;
bool skipped = false;
while (npc != state::NO_NEXT)
{
// If the next available PC is an unmerged `ret' state, then
// we aren't yet ready to handle it. That's because we would
// need all kind of special cases to do so. So instead we
// defer this jump until after we've processed it via a
// fall-through. This has to happen because the instruction
// before this one must be a `jsr'.
if (! states[npc]->is_unmerged_ret_state (current_method->max_locals))
{
*prev_loc = states[npc]->next;
states[npc]->next = state::INVALID;
return npc;
}
skipped = true;
prev_loc = &states[npc]->next;
npc = states[npc]->next;
}
// If we've skipped states and there is nothing else, that's a
// bug.
if (skipped)
verify_fail ("pop_jump: can't happen");
return state::NO_NEXT;
}
void invalidate_pc ()
{
PC = state::NO_NEXT;
}
void note_branch_target (int pc, bool is_jsr_target = false)
{
// Don't check `pc <= PC', because we've advanced PC after
// fetching the target and we haven't yet checked the next
// instruction.
if (pc < PC && ! (flags[pc] & FLAG_INSN_START))
verify_fail ("branch not to instruction start", start_PC);
flags[pc] |= FLAG_BRANCH_TARGET;
if (is_jsr_target)
{
// Record the jsr which called this instruction.
subr_info *info = (subr_info *) _Jv_Malloc (sizeof (subr_info));
info->pc = PC;
info->next = jsr_ptrs[pc];
jsr_ptrs[pc] = info;
}
}
void skip_padding ()
{
while ((PC % 4) > 0)
if (get_byte () != 0)
verify_fail ("found nonzero padding byte");
}
// Return the subroutine to which the instruction at PC belongs.
int get_subroutine (int pc)
{
if (states[pc] == NULL)
return 0;
return states[pc]->subroutine;
}
// Do the work for a `ret' instruction. INDEX is the index into the
// local variables.
void handle_ret_insn (int index)
{
get_variable (index, return_address_type);
int csub = current_state->subroutine;
if (csub == 0)
verify_fail ("no subroutine");
for (subr_info *subr = jsr_ptrs[csub]; subr != NULL; subr = subr->next)
{
// Temporarily modify the current state so it looks like we're
// in the enclosing context.
current_state->subroutine = get_subroutine (subr->pc);
if (subr->pc < PC)
current_state->check_no_uninitialized_objects (current_method->max_locals);
push_jump_merge (subr->pc, current_state, true);
}
current_state->subroutine = csub;
invalidate_pc ();
}
// We're in the subroutine SUB, calling a subroutine at DEST. Make
// sure this subroutine isn't already on the stack.
void check_nonrecursive_call (int sub, int dest)
{
if (sub == 0)
return;
if (sub == dest)
verify_fail ("recursive subroutine call");
for (subr_info *info = jsr_ptrs[sub]; info != NULL; info = info->next)
check_nonrecursive_call (get_subroutine (info->pc), dest);
}
void handle_jsr_insn (int offset)
{
int npc = compute_jump (offset);
if (npc < PC)
current_state->check_no_uninitialized_objects (current_method->max_locals);
check_nonrecursive_call (current_state->subroutine, npc);
// Temporarily modify the current state so that it looks like we are
// in the subroutine.
push_type (return_address_type);
int save = current_state->subroutine;
current_state->subroutine = npc;
// Merge into the subroutine.
push_jump_merge (npc, current_state);
// Undo our modifications.
current_state->subroutine = save;
pop_type (return_address_type);
}
jclass construct_primitive_array_type (type_val prim)
{
jclass k = NULL;
switch (prim)
{
case boolean_type:
k = JvPrimClass (boolean);
break;
case char_type:
k = JvPrimClass (char);
break;
case float_type:
k = JvPrimClass (float);
break;
case double_type:
k = JvPrimClass (double);
break;
case byte_type:
k = JvPrimClass (byte);
break;
case short_type:
k = JvPrimClass (short);
break;
case int_type:
k = JvPrimClass (int);
break;
case long_type:
k = JvPrimClass (long);
break;
default:
verify_fail ("unknown type in construct_primitive_array_type");
}
k = _Jv_GetArrayClass (k, NULL);
return k;
}
// This pass computes the location of branch targets and also
// instruction starts.
void branch_prepass ()
{
flags = (char *) _Jv_Malloc (current_method->code_length);
jsr_ptrs = (subr_info **) _Jv_Malloc (sizeof (subr_info *)
* current_method->code_length);
for (int i = 0; i < current_method->code_length; ++i)
{
flags[i] = 0;
jsr_ptrs[i] = NULL;
}
bool last_was_jsr = false;
PC = 0;
while (PC < current_method->code_length)
{
// Set `start_PC' early so that error checking can have the
// correct value.
start_PC = PC;
flags[PC] |= FLAG_INSN_START;
// If the previous instruction was a jsr, then the next
// instruction is a branch target -- the branch being the
// corresponding `ret'.
if (last_was_jsr)
note_branch_target (PC);
last_was_jsr = false;
java_opcode opcode = (java_opcode) bytecode[PC++];
switch (opcode)
{
case op_nop:
case op_aconst_null:
case op_iconst_m1:
case op_iconst_0:
case op_iconst_1:
case op_iconst_2:
case op_iconst_3:
case op_iconst_4:
case op_iconst_5:
case op_lconst_0:
case op_lconst_1:
case op_fconst_0:
case op_fconst_1:
case op_fconst_2:
case op_dconst_0:
case op_dconst_1:
case op_iload_0:
case op_iload_1:
case op_iload_2:
case op_iload_3:
case op_lload_0:
case op_lload_1:
case op_lload_2:
case op_lload_3:
case op_fload_0:
case op_fload_1:
case op_fload_2:
case op_fload_3:
case op_dload_0:
case op_dload_1:
case op_dload_2:
case op_dload_3:
case op_aload_0:
case op_aload_1:
case op_aload_2:
case op_aload_3:
case op_iaload:
case op_laload:
case op_faload:
case op_daload:
case op_aaload:
case op_baload:
case op_caload:
case op_saload:
case op_istore_0:
case op_istore_1:
case op_istore_2:
case op_istore_3:
case op_lstore_0:
case op_lstore_1:
case op_lstore_2:
case op_lstore_3:
case op_fstore_0:
case op_fstore_1:
case op_fstore_2:
case op_fstore_3:
case op_dstore_0:
case op_dstore_1:
case op_dstore_2:
case op_dstore_3:
case op_astore_0:
case op_astore_1:
case op_astore_2:
case op_astore_3:
case op_iastore:
case op_lastore:
case op_fastore:
case op_dastore:
case op_aastore:
case op_bastore:
case op_castore:
case op_sastore:
case op_pop:
case op_pop2:
case op_dup:
case op_dup_x1:
case op_dup_x2:
case op_dup2:
case op_dup2_x1:
case op_dup2_x2:
case op_swap:
case op_iadd:
case op_isub:
case op_imul:
case op_idiv:
case op_irem:
case op_ishl:
case op_ishr:
case op_iushr:
case op_iand:
case op_ior:
case op_ixor:
case op_ladd:
case op_lsub:
case op_lmul:
case op_ldiv:
case op_lrem:
case op_lshl:
case op_lshr:
case op_lushr:
case op_land:
case op_lor:
case op_lxor:
case op_fadd:
case op_fsub:
case op_fmul:
case op_fdiv:
case op_frem:
case op_dadd:
case op_dsub:
case op_dmul:
case op_ddiv:
case op_drem:
case op_ineg:
case op_i2b:
case op_i2c:
case op_i2s:
case op_lneg:
case op_fneg:
case op_dneg:
case op_i2l:
case op_i2f:
case op_i2d:
case op_l2i:
case op_l2f:
case op_l2d:
case op_f2i:
case op_f2l:
case op_f2d:
case op_d2i:
case op_d2l:
case op_d2f:
case op_lcmp:
case op_fcmpl:
case op_fcmpg:
case op_dcmpl:
case op_dcmpg:
case op_monitorenter:
case op_monitorexit:
case op_ireturn:
case op_lreturn:
case op_freturn:
case op_dreturn:
case op_areturn:
case op_return:
case op_athrow:
case op_arraylength:
break;
case op_bipush:
case op_ldc:
case op_iload:
case op_lload:
case op_fload:
case op_dload:
case op_aload:
case op_istore:
case op_lstore:
case op_fstore:
case op_dstore:
case op_astore:
case op_ret:
case op_newarray:
get_byte ();
break;
case op_iinc:
case op_sipush:
case op_ldc_w:
case op_ldc2_w:
case op_getstatic:
case op_getfield:
case op_putfield:
case op_putstatic:
case op_new:
case op_anewarray:
case op_instanceof:
case op_checkcast:
case op_invokespecial:
case op_invokestatic:
case op_invokevirtual:
get_short ();
break;
case op_multianewarray:
get_short ();
get_byte ();
break;
case op_jsr:
last_was_jsr = true;
// Fall through.
case op_ifeq:
case op_ifne:
case op_iflt:
case op_ifge:
case op_ifgt:
case op_ifle:
case op_if_icmpeq:
case op_if_icmpne:
case op_if_icmplt:
case op_if_icmpge:
case op_if_icmpgt:
case op_if_icmple:
case op_if_acmpeq:
case op_if_acmpne:
case op_ifnull:
case op_ifnonnull:
case op_goto:
note_branch_target (compute_jump (get_short ()), last_was_jsr);
break;
case op_tableswitch:
{
skip_padding ();
note_branch_target (compute_jump (get_int ()));
jint low = get_int ();
jint hi = get_int ();
if (low > hi)
verify_fail ("invalid tableswitch", start_PC);
for (int i = low; i <= hi; ++i)
note_branch_target (compute_jump (get_int ()));
}
break;
case op_lookupswitch:
{
skip_padding ();
note_branch_target (compute_jump (get_int ()));
int npairs = get_int ();
if (npairs < 0)
verify_fail ("too few pairs in lookupswitch", start_PC);
while (npairs-- > 0)
{
get_int ();
note_branch_target (compute_jump (get_int ()));
}
}
break;
case op_invokeinterface:
get_short ();
get_byte ();
get_byte ();
break;
case op_wide:
{
opcode = (java_opcode) get_byte ();
get_short ();
if (opcode == op_iinc)
get_short ();
}
break;
case op_jsr_w:
last_was_jsr = true;
// Fall through.
case op_goto_w:
note_branch_target (compute_jump (get_int ()), last_was_jsr);
break;
default:
verify_fail ("unrecognized instruction in branch_prepass",
start_PC);
}
// See if any previous branch tried to branch to the middle of
// this instruction.
for (int pc = start_PC + 1; pc < PC; ++pc)
{
if ((flags[pc] & FLAG_BRANCH_TARGET))
verify_fail ("branch to middle of instruction", pc);
}
}
// Verify exception handlers.
for (int i = 0; i < current_method->exc_count; ++i)
{
if (! (flags[exception[i].handler_pc] & FLAG_INSN_START))
verify_fail ("exception handler not at instruction start",
exception[i].handler_pc);
if (! (flags[exception[i].start_pc] & FLAG_INSN_START))
verify_fail ("exception start not at instruction start",
exception[i].start_pc);
if (exception[i].end_pc != current_method->code_length
&& ! (flags[exception[i].end_pc] & FLAG_INSN_START))
verify_fail ("exception end not at instruction start",
exception[i].end_pc);
flags[exception[i].handler_pc] |= FLAG_BRANCH_TARGET;
}
}
void check_pool_index (int index)
{
if (index < 0 || index >= current_class->constants.size)
verify_fail ("constant pool index out of range", start_PC);
}
type check_class_constant (int index)
{
check_pool_index (index);
_Jv_Constants *pool = &current_class->constants;
if (pool->tags[index] == JV_CONSTANT_ResolvedClass)
return type (pool->data[index].clazz);
else if (pool->tags[index] == JV_CONSTANT_Class)
return type (pool->data[index].utf8);
verify_fail ("expected class constant", start_PC);
}
type check_constant (int index)
{
check_pool_index (index);
_Jv_Constants *pool = &current_class->constants;
if (pool->tags[index] == JV_CONSTANT_ResolvedString
|| pool->tags[index] == JV_CONSTANT_String)
return type (&java::lang::String::class$);
else if (pool->tags[index] == JV_CONSTANT_Integer)
return type (int_type);
else if (pool->tags[index] == JV_CONSTANT_Float)
return type (float_type);
verify_fail ("String, int, or float constant expected", start_PC);
}
type check_wide_constant (int index)
{
check_pool_index (index);
_Jv_Constants *pool = &current_class->constants;
if (pool->tags[index] == JV_CONSTANT_Long)
return type (long_type);
else if (pool->tags[index] == JV_CONSTANT_Double)
return type (double_type);
verify_fail ("long or double constant expected", start_PC);
}
// Helper for both field and method. These are laid out the same in
// the constant pool.
type handle_field_or_method (int index, int expected,
_Jv_Utf8Const **name,
_Jv_Utf8Const **fmtype)
{
check_pool_index (index);
_Jv_Constants *pool = &current_class->constants;
if (pool->tags[index] != expected)
verify_fail ("didn't see expected constant", start_PC);
// Once we know we have a Fieldref or Methodref we assume that it
// is correctly laid out in the constant pool. I think the code
// in defineclass.cc guarantees this.
_Jv_ushort class_index, name_and_type_index;
_Jv_loadIndexes (&pool->data[index],
class_index,
name_and_type_index);
_Jv_ushort name_index, desc_index;
_Jv_loadIndexes (&pool->data[name_and_type_index],
name_index, desc_index);
*name = pool->data[name_index].utf8;
*fmtype = pool->data[desc_index].utf8;
return check_class_constant (class_index);
}
// Return field's type, compute class' type if requested.
type check_field_constant (int index, type *class_type = NULL)
{
_Jv_Utf8Const *name, *field_type;
type ct = handle_field_or_method (index,
JV_CONSTANT_Fieldref,
&name, &field_type);
if (class_type)
*class_type = ct;
if (field_type->data[0] == '[' || field_type->data[0] == 'L')
return type (field_type);
return get_type_val_for_signature (field_type->data[0]);
}
type check_method_constant (int index, bool is_interface,
_Jv_Utf8Const **method_name,
_Jv_Utf8Const **method_signature)
{
return handle_field_or_method (index,
(is_interface
? JV_CONSTANT_InterfaceMethodref
: JV_CONSTANT_Methodref),
method_name, method_signature);
}
type get_one_type (char *&p)
{
char *start = p;
int arraycount = 0;
while (*p == '[')
{
++arraycount;
++p;
}
char v = *p++;
if (v == 'L')
{
while (*p != ';')
++p;
++p;
_Jv_Utf8Const *name = make_utf8_const (start, p - start);
return type (name);
}
// Casting to jchar here is ok since we are looking at an ASCII
// character.
type_val rt = get_type_val_for_signature (jchar (v));
if (arraycount == 0)
{
// Callers of this function eventually push their arguments on
// the stack. So, promote them here.
return type (rt).promote ();
}
jclass k = construct_primitive_array_type (rt);
while (--arraycount > 0)
k = _Jv_GetArrayClass (k, NULL);
return type (k);
}
void compute_argument_types (_Jv_Utf8Const *signature,
type *types)
{
char *p = signature->data;
// Skip `('.
++p;
int i = 0;
while (*p != ')')
types[i++] = get_one_type (p);
}
type compute_return_type (_Jv_Utf8Const *signature)
{
char *p = signature->data;
while (*p != ')')
++p;
++p;
return get_one_type (p);
}
void check_return_type (type onstack)
{
type rt = compute_return_type (current_method->self->signature);
if (! rt.compatible (onstack))
verify_fail ("incompatible return type", start_PC);
}
// Initialize the stack for the new method. Returns true if this
// method is an instance initializer.
bool initialize_stack ()
{
int var = 0;
bool is_init = false;
using namespace java::lang::reflect;
if (! Modifier::isStatic (current_method->self->accflags))
{
type kurr (current_class);
if (_Jv_equalUtf8Consts (current_method->self->name, gcj::init_name))
{
kurr.set_uninitialized (type::SELF);
is_init = true;
}
set_variable (0, kurr);
current_state->set_this_type (kurr);
++var;
}
// We have to handle wide arguments specially here.
int arg_count = _Jv_count_arguments (current_method->self->signature);
type arg_types[arg_count];
compute_argument_types (current_method->self->signature, arg_types);
for (int i = 0; i < arg_count; ++i)
{
set_variable (var, arg_types[i]);
++var;
if (arg_types[i].iswide ())
++var;
}
return is_init;
}
void verify_instructions_0 ()
{
current_state = new state (current_method->max_stack,
current_method->max_locals);
PC = 0;
start_PC = 0;
// True if we are verifying an instance initializer.
bool this_is_init = initialize_stack ();
states = (state **) _Jv_Malloc (sizeof (state *)
* current_method->code_length);
for (int i = 0; i < current_method->code_length; ++i)
states[i] = NULL;
next_verify_pc = state::NO_NEXT;
while (true)
{
// If the PC was invalidated, get a new one from the work list.
if (PC == state::NO_NEXT)
{
PC = pop_jump ();
if (PC == state::INVALID)
verify_fail ("can't happen: saw state::INVALID");
if (PC == state::NO_NEXT)
break;
// Set up the current state.
current_state->copy (states[PC], current_method->max_stack,
current_method->max_locals);
}
else
{
// Control can't fall off the end of the bytecode. We
// only need to check this in the fall-through case,
// because branch bounds are checked when they are
// pushed.
if (PC >= current_method->code_length)
verify_fail ("fell off end");
// We only have to do this checking in the situation where
// control flow falls through from the previous
// instruction. Otherwise merging is done at the time we
// push the branch.
if (states[PC] != NULL)
{
// We've already visited this instruction. So merge
// the states together. If this yields no change then
// we don't have to re-verify. However, if the new
// state is an the result of an unmerged `ret', we
// must continue through it.
debug_print ("== Fall through merge\n");
states[PC]->print ("Old", PC, current_method->max_stack,
current_method->max_locals);
current_state->print ("Cur", PC, current_method->max_stack,
current_method->max_locals);
if (! current_state->merge (states[PC], false,
current_method->max_locals)
&& ! states[PC]->is_unmerged_ret_state (current_method->max_locals))
{
debug_print ("== Fall through optimization\n");
invalidate_pc ();
continue;
}
// Save a copy of it for later.
states[PC]->copy (current_state, current_method->max_stack,
current_method->max_locals);
current_state->print ("New", PC, current_method->max_stack,
current_method->max_locals);
}
}
// We only have to keep saved state at branch targets. If
// we're at a branch target and the state here hasn't been set
// yet, we set it now.
if (states[PC] == NULL && (flags[PC] & FLAG_BRANCH_TARGET))
{
states[PC] = new state (current_state, current_method->max_stack,
current_method->max_locals);
}
// Set this before handling exceptions so that debug output is
// sane.
start_PC = PC;
// Update states for all active exception handlers. Ordinarily
// there are not many exception handlers. So we simply run
// through them all.
for (int i = 0; i < current_method->exc_count; ++i)
{
if (PC >= exception[i].start_pc && PC < exception[i].end_pc)
{
type handler (&java::lang::Throwable::class$);
if (exception[i].handler_type != 0)
handler = check_class_constant (exception[i].handler_type);
push_exception_jump (handler, exception[i].handler_pc);
}
}
current_state->print (" ", PC, current_method->max_stack,
current_method->max_locals);
java_opcode opcode = (java_opcode) bytecode[PC++];
switch (opcode)
{
case op_nop:
break;
case op_aconst_null:
push_type (null_type);
break;
case op_iconst_m1:
case op_iconst_0:
case op_iconst_1:
case op_iconst_2:
case op_iconst_3:
case op_iconst_4:
case op_iconst_5:
push_type (int_type);
break;
case op_lconst_0:
case op_lconst_1:
push_type (long_type);
break;
case op_fconst_0:
case op_fconst_1:
case op_fconst_2:
push_type (float_type);
break;
case op_dconst_0:
case op_dconst_1:
push_type (double_type);
break;
case op_bipush:
get_byte ();
push_type (int_type);
break;
case op_sipush:
get_short ();
push_type (int_type);
break;
case op_ldc:
push_type (check_constant (get_byte ()));
break;
case op_ldc_w:
push_type (check_constant (get_ushort ()));
break;
case op_ldc2_w:
push_type (check_wide_constant (get_ushort ()));
break;
case op_iload:
push_type (get_variable (get_byte (), int_type));
break;
case op_lload:
push_type (get_variable (get_byte (), long_type));
break;
case op_fload:
push_type (get_variable (get_byte (), float_type));
break;
case op_dload:
push_type (get_variable (get_byte (), double_type));
break;
case op_aload:
push_type (get_variable (get_byte (), reference_type));
break;
case op_iload_0:
case op_iload_1:
case op_iload_2:
case op_iload_3:
push_type (get_variable (opcode - op_iload_0, int_type));
break;
case op_lload_0:
case op_lload_1:
case op_lload_2:
case op_lload_3:
push_type (get_variable (opcode - op_lload_0, long_type));
break;
case op_fload_0:
case op_fload_1:
case op_fload_2:
case op_fload_3:
push_type (get_variable (opcode - op_fload_0, float_type));
break;
case op_dload_0:
case op_dload_1:
case op_dload_2:
case op_dload_3:
push_type (get_variable (opcode - op_dload_0, double_type));
break;
case op_aload_0:
case op_aload_1:
case op_aload_2:
case op_aload_3:
push_type (get_variable (opcode - op_aload_0, reference_type));
break;
case op_iaload:
pop_type (int_type);
push_type (require_array_type (pop_type (reference_type),
int_type));
break;
case op_laload:
pop_type (int_type);
push_type (require_array_type (pop_type (reference_type),
long_type));
break;
case op_faload:
pop_type (int_type);
push_type (require_array_type (pop_type (reference_type),
float_type));
break;
case op_daload:
pop_type (int_type);
push_type (require_array_type (pop_type (reference_type),
double_type));
break;
case op_aaload:
pop_type (int_type);
push_type (require_array_type (pop_type (reference_type),
reference_type));
break;
case op_baload:
pop_type (int_type);
require_array_type (pop_type (reference_type), byte_type);
push_type (int_type);
break;
case op_caload:
pop_type (int_type);
require_array_type (pop_type (reference_type), char_type);
push_type (int_type);
break;
case op_saload:
pop_type (int_type);
require_array_type (pop_type (reference_type), short_type);
push_type (int_type);
break;
case op_istore:
set_variable (get_byte (), pop_type (int_type));
break;
case op_lstore:
set_variable (get_byte (), pop_type (long_type));
break;
case op_fstore:
set_variable (get_byte (), pop_type (float_type));
break;
case op_dstore:
set_variable (get_byte (), pop_type (double_type));
break;
case op_astore:
set_variable (get_byte (), pop_ref_or_return ());
break;
case op_istore_0:
case op_istore_1:
case op_istore_2:
case op_istore_3:
set_variable (opcode - op_istore_0, pop_type (int_type));
break;
case op_lstore_0:
case op_lstore_1:
case op_lstore_2:
case op_lstore_3:
set_variable (opcode - op_lstore_0, pop_type (long_type));
break;
case op_fstore_0:
case op_fstore_1:
case op_fstore_2:
case op_fstore_3:
set_variable (opcode - op_fstore_0, pop_type (float_type));
break;
case op_dstore_0:
case op_dstore_1:
case op_dstore_2:
case op_dstore_3:
set_variable (opcode - op_dstore_0, pop_type (double_type));
break;
case op_astore_0:
case op_astore_1:
case op_astore_2:
case op_astore_3:
set_variable (opcode - op_astore_0, pop_ref_or_return ());
break;
case op_iastore:
pop_type (int_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), int_type);
break;
case op_lastore:
pop_type (long_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), long_type);
break;
case op_fastore:
pop_type (float_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), float_type);
break;
case op_dastore:
pop_type (double_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), double_type);
break;
case op_aastore:
pop_type (reference_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), reference_type);
break;
case op_bastore:
pop_type (int_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), byte_type);
break;
case op_castore:
pop_type (int_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), char_type);
break;
case op_sastore:
pop_type (int_type);
pop_type (int_type);
require_array_type (pop_type (reference_type), short_type);
break;
case op_pop:
pop32 ();
break;
case op_pop2:
pop64 ();
break;
case op_dup:
{
type t = pop32 ();
push_type (t);
push_type (t);
}
break;
case op_dup_x1:
{
type t1 = pop32 ();
type t2 = pop32 ();
push_type (t1);
push_type (t2);
push_type (t1);
}
break;
case op_dup_x2:
{
type t1 = pop32 ();
type t2 = pop_raw ();
if (! t2.iswide ())
{
type t3 = pop32 ();
push_type (t1);
push_type (t3);
}
else
push_type (t1);
push_type (t2);
push_type (t1);
}
break;
case op_dup2:
{
type t = pop_raw ();
if (! t.iswide ())
{
type t2 = pop32 ();
push_type (t2);
push_type (t);
push_type (t2);
}
push_type (t);
}
break;
case op_dup2_x1:
{
type t1 = pop_raw ();
type t2 = pop32 ();
if (! t1.iswide ())
{
type t3 = pop32 ();
push_type (t2);
push_type (t1);
push_type (t3);
}
else
push_type (t1);
push_type (t2);
push_type (t1);
}
break;
case op_dup2_x2:
{
// FIXME
type t1 = pop_raw ();
if (t1.iswide ())
{
type t2 = pop_raw ();
if (t2.iswide ())
{
push_type (t1);
push_type (t2);
}
else
{
type t3 = pop32 ();
push_type (t1);
push_type (t3);
push_type (t2);
}
push_type (t1);
}
else
{
type t2 = pop32 ();
type t3 = pop_raw ();
if (t3.iswide ())
{
push_type (t2);
push_type (t1);
}
else
{
type t4 = pop32 ();
push_type (t2);
push_type (t1);
push_type (t4);
}
push_type (t3);
push_type (t2);
push_type (t1);
}
}
break;
case op_swap:
{
type t1 = pop32 ();
type t2 = pop32 ();
push_type (t1);
push_type (t2);
}
break;
case op_iadd:
case op_isub:
case op_imul:
case op_idiv:
case op_irem:
case op_ishl:
case op_ishr:
case op_iushr:
case op_iand:
case op_ior:
case op_ixor:
pop_type (int_type);
push_type (pop_type (int_type));
break;
case op_ladd:
case op_lsub:
case op_lmul:
case op_ldiv:
case op_lrem:
case op_land:
case op_lor:
case op_lxor:
pop_type (long_type);
push_type (pop_type (long_type));
break;
case op_lshl:
case op_lshr:
case op_lushr:
pop_type (int_type);
push_type (pop_type (long_type));
break;
case op_fadd:
case op_fsub:
case op_fmul:
case op_fdiv:
case op_frem:
pop_type (float_type);
push_type (pop_type (float_type));
break;
case op_dadd:
case op_dsub:
case op_dmul:
case op_ddiv:
case op_drem:
pop_type (double_type);
push_type (pop_type (double_type));
break;
case op_ineg:
case op_i2b:
case op_i2c:
case op_i2s:
push_type (pop_type (int_type));
break;
case op_lneg:
push_type (pop_type (long_type));
break;
case op_fneg:
push_type (pop_type (float_type));
break;
case op_dneg:
push_type (pop_type (double_type));
break;
case op_iinc:
get_variable (get_byte (), int_type);
get_byte ();
break;
case op_i2l:
pop_type (int_type);
push_type (long_type);
break;
case op_i2f:
pop_type (int_type);
push_type (float_type);
break;
case op_i2d:
pop_type (int_type);
push_type (double_type);
break;
case op_l2i:
pop_type (long_type);
push_type (int_type);
break;
case op_l2f:
pop_type (long_type);
push_type (float_type);
break;
case op_l2d:
pop_type (long_type);
push_type (double_type);
break;
case op_f2i:
pop_type (float_type);
push_type (int_type);
break;
case op_f2l:
pop_type (float_type);
push_type (long_type);
break;
case op_f2d:
pop_type (float_type);
push_type (double_type);
break;
case op_d2i:
pop_type (double_type);
push_type (int_type);
break;
case op_d2l:
pop_type (double_type);
push_type (long_type);
break;
case op_d2f:
pop_type (double_type);
push_type (float_type);
break;
case op_lcmp:
pop_type (long_type);
pop_type (long_type);
push_type (int_type);
break;
case op_fcmpl:
case op_fcmpg:
pop_type (float_type);
pop_type (float_type);
push_type (int_type);
break;
case op_dcmpl:
case op_dcmpg:
pop_type (double_type);
pop_type (double_type);
push_type (int_type);
break;
case op_ifeq:
case op_ifne:
case op_iflt:
case op_ifge:
case op_ifgt:
case op_ifle:
pop_type (int_type);
push_jump (get_short ());
break;
case op_if_icmpeq:
case op_if_icmpne:
case op_if_icmplt:
case op_if_icmpge:
case op_if_icmpgt:
case op_if_icmple:
pop_type (int_type);
pop_type (int_type);
push_jump (get_short ());
break;
case op_if_acmpeq:
case op_if_acmpne:
pop_type (reference_type);
pop_type (reference_type);
push_jump (get_short ());
break;
case op_goto:
push_jump (get_short ());
invalidate_pc ();
break;
case op_jsr:
handle_jsr_insn (get_short ());
break;
case op_ret:
handle_ret_insn (get_byte ());
break;
case op_tableswitch:
{
pop_type (int_type);
skip_padding ();
push_jump (get_int ());
jint low = get_int ();
jint high = get_int ();
// Already checked LOW -vs- HIGH.
for (int i = low; i <= high; ++i)
push_jump (get_int ());
invalidate_pc ();
}
break;
case op_lookupswitch:
{
pop_type (int_type);
skip_padding ();
push_jump (get_int ());
jint npairs = get_int ();
// Already checked NPAIRS >= 0.
jint lastkey = 0;
for (int i = 0; i < npairs; ++i)
{
jint key = get_int ();
if (i > 0 && key <= lastkey)
verify_fail ("lookupswitch pairs unsorted", start_PC);
lastkey = key;
push_jump (get_int ());
}
invalidate_pc ();
}
break;
case op_ireturn:
check_return_type (pop_type (int_type));
invalidate_pc ();
break;
case op_lreturn:
check_return_type (pop_type (long_type));
invalidate_pc ();
break;
case op_freturn:
check_return_type (pop_type (float_type));
invalidate_pc ();
break;
case op_dreturn:
check_return_type (pop_type (double_type));
invalidate_pc ();
break;
case op_areturn:
check_return_type (pop_type (reference_type));
invalidate_pc ();
break;
case op_return:
// We only need to check this when the return type is
// void, because all instance initializers return void.
if (this_is_init)
current_state->check_this_initialized ();
check_return_type (void_type);
invalidate_pc ();
break;
case op_getstatic:
push_type (check_field_constant (get_ushort ()));
break;
case op_putstatic:
pop_type (check_field_constant (get_ushort ()));
break;
case op_getfield:
{
type klass;
type field = check_field_constant (get_ushort (), &klass);
pop_type (klass);
push_type (field);
}
break;
case op_putfield:
{
type klass;
type field = check_field_constant (get_ushort (), &klass);
pop_type (field);
// We have an obscure special case here: we can use
// `putfield' on a field declared in this class, even if
// `this' has not yet been initialized.
if (! current_state->this_type.isinitialized ()
&& current_state->this_type.pc == type::SELF)
klass.set_uninitialized (type::SELF);
pop_type (klass);
}
break;
case op_invokevirtual:
case op_invokespecial:
case op_invokestatic:
case op_invokeinterface:
{
_Jv_Utf8Const *method_name, *method_signature;
type class_type
= check_method_constant (get_ushort (),
opcode == op_invokeinterface,
&method_name,
&method_signature);
int arg_count = _Jv_count_arguments (method_signature);
if (opcode == op_invokeinterface)
{
int nargs = get_byte ();
if (nargs == 0)
verify_fail ("too few arguments to invokeinterface",
start_PC);
if (get_byte () != 0)
verify_fail ("invokeinterface dummy byte is wrong",
start_PC);
if (nargs - 1 != arg_count)
verify_fail ("wrong argument count for invokeinterface",
start_PC);
}
bool is_init = false;
if (_Jv_equalUtf8Consts (method_name, gcj::init_name))
{
is_init = true;
if (opcode != op_invokespecial)
verify_fail ("can't invoke <init>", start_PC);
}
else if (method_name->data[0] == '<')
verify_fail ("can't invoke method starting with `<'",
start_PC);
// Pop arguments and check types.
type arg_types[arg_count];
compute_argument_types (method_signature, arg_types);
for (int i = arg_count - 1; i >= 0; --i)
pop_type (arg_types[i]);
if (opcode != op_invokestatic)
{
type t = class_type;
if (is_init)
{
// In this case the PC doesn't matter.
t.set_uninitialized (type::UNINIT);
}
t = pop_type (t);
if (is_init)
current_state->set_initialized (t.get_pc (),
current_method->max_locals);
}
type rt = compute_return_type (method_signature);
if (! rt.isvoid ())
push_type (rt);
}
break;
case op_new:
{
type t = check_class_constant (get_ushort ());
if (t.isarray () || t.isinterface () || t.isabstract ())
verify_fail ("type is array, interface, or abstract",
start_PC);
t.set_uninitialized (start_PC);
push_type (t);
}
break;
case op_newarray:
{
int atype = get_byte ();
// We intentionally have chosen constants to make this
// valid.
if (atype < boolean_type || atype > long_type)
verify_fail ("type not primitive", start_PC);
pop_type (int_type);
push_type (construct_primitive_array_type (type_val (atype)));
}
break;
case op_anewarray:
pop_type (int_type);
push_type (check_class_constant (get_ushort ()).to_array ());
break;
case op_arraylength:
{
type t = pop_type (reference_type);
if (! t.isarray ())
verify_fail ("array type expected", start_PC);
push_type (int_type);
}
break;
case op_athrow:
pop_type (type (&java::lang::Throwable::class$));
invalidate_pc ();
break;
case op_checkcast:
pop_type (reference_type);
push_type (check_class_constant (get_ushort ()));
break;
case op_instanceof:
pop_type (reference_type);
check_class_constant (get_ushort ());
push_type (int_type);
break;
case op_monitorenter:
pop_type (reference_type);
break;
case op_monitorexit:
pop_type (reference_type);
break;
case op_wide:
{
switch (get_byte ())
{
case op_iload:
push_type (get_variable (get_ushort (), int_type));
break;
case op_lload:
push_type (get_variable (get_ushort (), long_type));
break;
case op_fload:
push_type (get_variable (get_ushort (), float_type));
break;
case op_dload:
push_type (get_variable (get_ushort (), double_type));
break;
case op_aload:
push_type (get_variable (get_ushort (), reference_type));
break;
case op_istore:
set_variable (get_ushort (), pop_type (int_type));
break;
case op_lstore:
set_variable (get_ushort (), pop_type (long_type));
break;
case op_fstore:
set_variable (get_ushort (), pop_type (float_type));
break;
case op_dstore:
set_variable (get_ushort (), pop_type (double_type));
break;
case op_astore:
set_variable (get_ushort (), pop_type (reference_type));
break;
case op_ret:
handle_ret_insn (get_short ());
break;
case op_iinc:
get_variable (get_ushort (), int_type);
get_short ();
break;
default:
verify_fail ("unrecognized wide instruction", start_PC);
}
}
break;
case op_multianewarray:
{
type atype = check_class_constant (get_ushort ());
int dim = get_byte ();
if (dim < 1)
verify_fail ("too few dimensions to multianewarray", start_PC);
atype.verify_dimensions (dim);
for (int i = 0; i < dim; ++i)
pop_type (int_type);
push_type (atype);
}
break;
case op_ifnull:
case op_ifnonnull:
pop_type (reference_type);
push_jump (get_short ());
break;
case op_goto_w:
push_jump (get_int ());
invalidate_pc ();
break;
case op_jsr_w:
handle_jsr_insn (get_int ());
break;
default:
// Unrecognized opcode.
verify_fail ("unrecognized instruction in verify_instructions_0",
start_PC);
}
}
}
public:
void verify_instructions ()
{
branch_prepass ();
verify_instructions_0 ();
}
_Jv_BytecodeVerifier (_Jv_InterpMethod *m)
{
// We just print the text as utf-8. This is just for debugging
// anyway.
debug_print ("--------------------------------\n");
debug_print ("-- Verifying method `%s'\n", m->self->name->data);
current_method = m;
bytecode = m->bytecode ();
exception = m->exceptions ();
current_class = m->defining_class;
states = NULL;
flags = NULL;
jsr_ptrs = NULL;
utf8_list = NULL;
}
~_Jv_BytecodeVerifier ()
{
if (states)
_Jv_Free (states);
if (flags)
_Jv_Free (flags);
if (jsr_ptrs)
_Jv_Free (jsr_ptrs);
while (utf8_list != NULL)
{
linked_utf8 *n = utf8_list->next;
_Jv_Free (utf8_list->val);
_Jv_Free (utf8_list);
utf8_list = n;
}
}
};
void
_Jv_VerifyMethod (_Jv_InterpMethod *meth)
{
_Jv_BytecodeVerifier v (meth);
v.verify_instructions ();
}
// FIXME: add more info, like PC, when required.
static void
verify_fail (char *s, jint pc)
{
using namespace java::lang;
StringBuffer *buf = new StringBuffer ();
buf->append (JvNewStringLatin1 ("verification failed"));
if (pc != -1)
{
buf->append (JvNewStringLatin1 (" at PC "));
buf->append (pc);
}
buf->append (JvNewStringLatin1 (": "));
buf->append (JvNewStringLatin1 (s));
throw new java::lang::VerifyError (buf->toString ());
}
#endif /* INTERPRETER */
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