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Fix possible overflow in calculation of canonical indices.

This commit is contained in:
Stephen Williams 2014-01-15 14:26:53 -08:00
parent ae1f8be277
commit 1fc4093191
5 changed files with 86 additions and 10 deletions
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2
elab_expr.cc
View File

@ -3964,7 +3964,7 @@ NetExpr* PEIdent::elaborate_expr_net_word_(Design*des, NetScope*scope,
indices_flags idx_flags;
indices_to_expressions(des, scope, this,
name_tail.index, net->unpacked_dimensions(),
need_const,
need_const, net->unpacked_count(),
idx_flags,
unpacked_indices,
unpacked_indices_const);

26
elab_lval.cc
View File

@ -201,6 +201,11 @@ NetAssign_* PEIdent::elaborate_lval(Design*des,
NetEvent* eve = 0;
perm_string method_name;
if (debug_elaborate) {
cerr << get_fileline() << ": PEIdent::elaborate_lval: "
<< "Elaborate l-value ident expression: " << *this << endl;
}
/* Try to detect the special case that we are in a method and
the identifier is a member of the class. */
if (NetAssign_*tmp = elaborate_lval_method_class_member_(des, scope))
@ -259,6 +264,13 @@ NetAssign_* PEIdent::elaborate_lval(Design*des,
}
ivl_assert(*this, reg);
if (debug_elaborate) {
cerr << get_fileline() << ": PEIdent::elaborate_lval: "
<< "Found l-value as reg."
<< " unpacked_dimensions()=" << reg->unpacked_dimensions() << endl;
}
// We are processing the tail of a string of names. For
// example, the verilog may be "a.b.c", so we are processing
// "c" at this point. (Note that if method_name is not nil,
@ -440,6 +452,11 @@ NetAssign_* PEIdent::elaborate_lval_net_word_(Design*des,
const name_component_t&name_tail = path_.back();
ivl_assert(*this, !name_tail.index.empty());
if (debug_elaborate) {
cerr << get_fileline() << ": PEIdent::elaborate_lval_net_word_: "
<< "Handle as n-dimensional array." << endl;
}
if (name_tail.index.size() < reg->unpacked_dimensions()) {
cerr << get_fileline() << ": error: Array " << reg->name()
<< " needs " << reg->unpacked_dimensions() << " indices,"
@ -448,6 +465,8 @@ NetAssign_* PEIdent::elaborate_lval_net_word_(Design*des,
return 0;
}
unsigned array_need_words = reg->unpacked_count();
// Make sure there are enough indices to address an array element.
const index_component_t&index_head = name_tail.index.front();
if (index_head.sel == index_component_t::SEL_PART) {
@ -465,7 +484,7 @@ NetAssign_* PEIdent::elaborate_lval_net_word_(Design*des,
indices_flags flags;
indices_to_expressions(des, scope, this,
name_tail.index, reg->unpacked_dimensions(),
false,
false, array_need_words,
flags,
unpacked_indices,
unpacked_indices_const);
@ -507,6 +526,11 @@ NetAssign_* PEIdent::elaborate_lval_net_word_(Design*des,
canon_index = new NetEConst(verinum(verinum::Vx));
canon_index->set_line(*this);
if (debug_elaborate) {
cerr << get_fileline() << ": PEIdent::elaborate_lval_net_word_: "
<< "canon_index=" << *canon_index << endl;
}
NetAssign_*lv = new NetAssign_(reg);
lv->set_word(canon_index);

2
elab_net.cc
View File

@ -607,7 +607,7 @@ NetNet* PEIdent::elaborate_lnet_common_(Design*des, NetScope*scope,
indices_flags flags;
indices_to_expressions(des, scope, this,
path_tail.index, sig->unpacked_dimensions(),
true,
true, sig->unpacked_count(),
flags,
unpacked_indices,
unpacked_indices_const);

58
netmisc.cc
View File

@ -468,12 +468,21 @@ void indices_to_expressions(Design*des, NetScope*scope,
const list<index_component_t>&src, unsigned count,
// True if the expression MUST be constant.
bool need_const,
// Total words in target array
unsigned need_addr,
// These are the outputs.
indices_flags&flags,
list<NetExpr*>&indices, list<long>&indices_const)
{
ivl_assert(*loc, count <= src.size());
int need_wid = ceil(log2(need_addr)) + 1;
if (debug_elaborate) {
cerr << loc->get_fileline() << ": indices_to_expressions: "
<< "To address " << need_addr << " words, "
<< "we need " << need_wid << " bits." << endl;
}
flags.invalid = false;
flags.variable = false;
flags.undefined = false;
@ -488,7 +497,7 @@ void indices_to_expressions(Design*des, NetScope*scope,
}
ivl_assert(*loc, cur->msb);
NetExpr*word_index = elab_and_eval(des, scope, cur->msb, -1, need_const);
NetExpr*word_index = elab_and_eval_min_width(des, scope, cur->msb, need_wid, need_const);
if (word_index == 0)
flags.invalid = true;
@ -730,13 +739,16 @@ NetExpr* condition_reduce(NetExpr*expr)
return cmp;
}
NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
int context_width, bool need_const, bool annotatable,
ivl_variable_type_t cast_type)
static NetExpr* do_elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
int context_width, bool need_const, bool annotatable,
bool width_is_min,
ivl_variable_type_t cast_type)
{
PExpr::width_mode_t mode = PExpr::SIZED;
if ((context_width == -2) && !gn_strict_expr_width_flag)
mode = PExpr::EXPAND;
if (width_is_min)
mode = PExpr::EXPAND;
pe->test_width(des, scope, mode);
@ -755,8 +767,10 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
<< *pe << endl;
cerr << pe->get_fileline() << ": : "
<< "returns type=" << pe->expr_type()
<< ", width=" << expr_width
<< ", context_width=" << context_width
<< ", signed=" << pe->has_sign()
<< ", width_is_min=" << width_is_min
<< ", expr_width=" << expr_width
<< ", mode=" << PExpr::width_mode_name(mode) << endl;
cerr << pe->get_fileline() << ": : "
<< "cast_type=" << cast_type << endl;
@ -764,7 +778,8 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
// If we can get the same result using a smaller expression
// width, do so.
if ((context_width > 0) && (pe->expr_type() != IVL_VT_REAL)
if ((context_width > 0) && (!width_is_min)
&& (pe->expr_type() != IVL_VT_REAL)
&& (expr_width > (unsigned)context_width)) {
expr_width = max(pe->min_width(), (unsigned)context_width);
@ -780,6 +795,11 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
if (annotatable)
flags |= PExpr::ANNOTATABLE;
if (debug_elaborate) {
cerr << pe->get_fileline() << ": elab_and_eval: "
<< "Calculated width is " << expr_width << "." << endl;
}
NetExpr*tmp = pe->elaborate_expr(des, scope, expr_width, flags);
if (tmp == 0) return 0;
@ -799,6 +819,13 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
}
}
// If the context_width sent is is actually the minimim width,
// then raise the context_width to be big enough for the
// lossless expression.
if (width_is_min && context_width > 0) {
context_width = max(context_width, (int)expr_width);
}
eval_expr(tmp, context_width);
if (NetEConst*ce = dynamic_cast<NetEConst*>(tmp)) {
@ -809,6 +836,23 @@ NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
return tmp;
}
NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
int context_width, bool need_const, bool annotatable,
ivl_variable_type_t cast_type)
{
return do_elab_and_eval(des, scope, pe, context_width,
need_const, annotatable, false, cast_type);
}
NetExpr* elab_and_eval_min_width(Design*des, NetScope*scope, PExpr*pe,
int context_width, bool need_const, bool annotatable,
ivl_variable_type_t cast_type)
{
ivl_assert(*pe, context_width > 0);
return do_elab_and_eval(des, scope, pe, context_width,
need_const, annotatable, true, cast_type);
}
NetExpr* elab_and_eval(Design*des, NetScope*scope, PExpr*pe,
ivl_type_t lv_net_type, bool need_const)
{
@ -1262,7 +1306,7 @@ NetExpr*collapse_array_exprs(Design*des, NetScope*scope,
indices_flags flags;
indices_to_expressions(des, scope, loc, indices,
net->packed_dimensions(),
false, flags, exprs, exprs_const);
false, net->unpacked_count(), flags, exprs, exprs_const);
ivl_assert(*loc, exprs.size() == net->packed_dimensions());
// Special Case: there is only 1 packed dimension, so the

8
netmisc.h
View File

@ -179,6 +179,8 @@ extern void indices_to_expressions(Design*des, NetScope*scope,
const list<index_component_t>&src, unsigned count,
// True if the expression MUST be constant.
bool need_const,
// Total array size, for sizing expressions
unsigned need_addr,
// These are the outputs.
indices_flags&flags,
list<NetExpr*>&indices,list<long>&indices_const);
@ -244,6 +246,12 @@ extern NetExpr* elab_and_eval(Design*des, NetScope*scope,
bool annotatable =false,
ivl_variable_type_t cast_type =IVL_VT_NO_TYPE);
extern NetExpr* elab_and_eval_min_width(Design*des, NetScope*scope,
PExpr*pe, int context_width,
bool need_const =false,
bool annotatable =false,
ivl_variable_type_t cast_type =IVL_VT_NO_TYPE);
/*
* This form of elab_and_eval uses the ivl_type_t to carry type
* information instead of the piecemeal form. We should transition to