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Index struct/union members within corresponding wire chunks

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This guards against access to bits outside of struct/union
members via dynamic indexing.
This commit is contained in:
Dag Lem 2023-02-28 18:45:55 +01:00
parent 79043cb849
commit 0d3423ddea
5 changed files with 68 additions and 32 deletions
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44
frontends/ast/simplify.cc
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@ -445,7 +445,7 @@ static AstNode *struct_index_lsb_offset(AstNode *lsb_offset, AstNode *rnode, Ast
stride /= get_struct_range_width(member_node, dimension);
auto right = normalize_struct_index(rnode->children.back(), member_node, dimension);
auto offset = stride > 1 ? multiply_by_const(right, stride) : right;
return new AstNode(AST_ADD, lsb_offset, offset);
return lsb_offset ? new AstNode(AST_ADD, lsb_offset, offset) : offset;
}
static AstNode *struct_index_msb_offset(AstNode *lsb_offset, AstNode *rnode, AstNode *member_node, int dimension, int stride)
@ -484,7 +484,7 @@ AstNode *AST::make_struct_member_range(AstNode *node, AstNode *member_node)
int range_right = member_node->range_right;
if (node->children.empty()) {
// no range operations apply, return the whole width
return make_range(range_left, range_right);
return make_range(range_left - range_right, 0);
}
if (node->children.size() != 1) {
@ -493,7 +493,7 @@ AstNode *AST::make_struct_member_range(AstNode *node, AstNode *member_node)
// Range operations
auto rnode = node->children[0];
auto lsb_offset = node_int(member_node->range_right);
AstNode *lsb_offset = NULL;
int stride = range_left - range_right + 1;
size_t i = 0;
@ -520,6 +520,17 @@ AstNode *AST::make_struct_member_range(AstNode *node, AstNode *member_node)
return new AstNode(AST_RANGE, msb_offset, lsb_offset);
}
AstNode *AST::get_struct_member(const AstNode *node)
{
AST::AstNode *member_node;
if (node->attributes.count(ID::wiretype) && (member_node = node->attributes.at(ID::wiretype)) &&
(member_node->type == AST_STRUCT_ITEM || member_node->type == AST_STRUCT || member_node->type == AST_UNION))
{
return member_node;
}
return NULL;
}
static void add_members_to_scope(AstNode *snode, std::string name)
{
// add all the members in a struct or union to local scope
@ -2696,7 +2707,14 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
goto skip_dynamic_range_lvalue_expansion;
int source_width = children[0]->id2ast->range_left - children[0]->id2ast->range_right + 1;
int source_offset = children[0]->id2ast->range_right;
int result_width = 1;
AST::AstNode *member_node = get_struct_member(children[0]);
if (member_node) {
// Clamp chunk to range of member within struct/union.
log_assert(!source_offset && !children[0]->id2ast->range_swapped);
source_width = member_node->range_left - member_node->range_right + 1;
}
AstNode *shift_expr = NULL;
AstNode *range = children[0]->children[0];
@ -2737,11 +2755,13 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
did_something = true;
newNode = new AstNode(AST_CASE, shift_expr);
for (int i = 0; i < source_width; i++) {
int start_bit = children[0]->id2ast->range_right + i;
int start_bit = source_offset + i;
int end_bit = std::min(start_bit+result_width,source_width) - 1;
AstNode *cond = new AstNode(AST_COND, mkconst_int(start_bit, true));
AstNode *lvalue = children[0]->clone();
lvalue->delete_children();
if (member_node)
lvalue->attributes[ID::wiretype] = member_node->clone();
lvalue->children.push_back(new AstNode(AST_RANGE,
mkconst_int(end_bit, true), mkconst_int(start_bit, true)));
cond->children.push_back(new AstNode(AST_BLOCK, new AstNode(type, lvalue, children[1]->clone())));
@ -2783,6 +2803,8 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
AstNode *lvalue = children[0]->clone();
lvalue->delete_children();
if (member_node)
lvalue->attributes[ID::wiretype] = member_node->clone();
AstNode *ref_mask = new AstNode(AST_IDENTIFIER);
ref_mask->str = wire_mask->str;
@ -2813,7 +2835,7 @@ bool AstNode::simplify(bool const_fold, bool at_zero, bool in_lvalue, int stage,
shamt = new AstNode(AST_TO_SIGNED, shamt);
// offset the shift amount by the lower bound of the dimension
int start_bit = children[0]->id2ast->range_right;
int start_bit = source_offset;
shamt = new AstNode(AST_SUB, shamt, mkconst_int(start_bit, true));
// reflect the shift amount if the dimension is swapped
@ -3403,11 +3425,8 @@ skip_dynamic_range_lvalue_expansion:;
log_file_error(filename, location.first_line, "Failed to resolve identifier %s for width detection!\n", buf->str.c_str());
// Check for item in packed struct / union
AST::AstNode *item_node;
if (id_ast->type == AST_WIRE &&
buf->attributes.count(ID::wiretype) && (item_node = buf->attributes[ID::wiretype]) &&
(item_node->type == AST_STRUCT_ITEM || item_node->type == AST_STRUCT || item_node->type == AST_UNION))
{
AST::AstNode *item_node = get_struct_member(buf);
if (id_ast->type == AST_WIRE && item_node) {
// The dimension of the original array expression is saved in the 'integer' field
dim += buf->integer;
if (item_node->multirange_dimensions.empty()) {
@ -4082,10 +4101,13 @@ replace_fcall_later:;
tmp_range_left = (param_width + 2*param_offset) - children[0]->range_right - 1;
tmp_range_right = (param_width + 2*param_offset) - children[0]->range_left - 1;
}
AST::AstNode *member_node = get_struct_member(this);
int chunk_offset = member_node ? member_node->range_right : 0;
log_assert(!(chunk_offset && param_upto));
for (int i = tmp_range_right; i <= tmp_range_left; i++) {
int index = i - param_offset;
if (0 <= index && index < param_width)
data.push_back(current_scope[str]->children[0]->bits[index]);
data.push_back(current_scope[str]->children[0]->bits[chunk_offset + index]);
else
data.push_back(RTLIL::State::Sx);
}