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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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6
frontends/ast/ast.cc
View file

@ -524,7 +524,13 @@ void AstNode::dumpVlog(FILE *f, std::string indent) const
break;
case AST_IDENTIFIER:
{
AST::AstNode *member_node = AST::get_struct_member(this);
if (member_node)
fprintf(f, "%s[%d:%d]", id2vl(str).c_str(), member_node->range_left, member_node->range_right);
else
fprintf(f, "%s", id2vl(str).c_str());
}
for (auto child : children)
child->dumpVlog(f, "");
break;

1
frontends/ast/ast.h
View file

@ -380,6 +380,7 @@ namespace AST
// struct helper exposed from simplify for genrtlil
AstNode *make_struct_member_range(AstNode *node, AstNode *member_node);
AstNode *get_struct_member(const AstNode *node);
// generate standard $paramod... derived module name; parameters should be
// in the order they are declared in the instantiated module

44
frontends/ast/genrtlil.cc
View file

@ -1375,6 +1375,7 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
RTLIL::SigChunk chunk;
bool is_interface = false;
AST::AstNode *member_node = NULL;
int add_undef_bits_msb = 0;
int add_undef_bits_lsb = 0;
@ -1438,23 +1439,26 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
chunk.width = wire->width;
chunk.offset = 0;
if ((member_node = get_struct_member(this))) {
// Clamp wire chunk to range of member within struct/union.
chunk.width = member_node->range_left - member_node->range_right + 1;
chunk.offset = member_node->range_right;
}
use_const_chunk:
if (children.size() != 0) {
if (children[0]->type != AST_RANGE)
log_file_error(filename, location.first_line, "Single range expected.\n");
int source_width = id2ast->range_left - id2ast->range_right + 1;
int source_offset = id2ast->range_right;
int item_left = source_width - 1;
int item_right = 0;
int chunk_left = source_width - 1;
int chunk_right = 0;
// Check for item in struct/union.
AST::AstNode *item_node;
if (attributes.count(ID::wiretype) && (item_node = attributes[ID::wiretype]) &&
(item_node->type == AST_STRUCT_ITEM || item_node->type == AST_STRUCT || item_node->type == AST_UNION))
{
// Clamp chunk to range of item within struct/union.
item_left = item_node->range_left;
item_right = item_node->range_right;
if (member_node) {
// Clamp wire chunk to range of member within struct/union.
log_assert(!source_offset && !id2ast->range_swapped);
chunk_left = chunk.offset + chunk.width - 1;
chunk_right = chunk.offset;
}
if (!children[0]->range_valid) {
@ -1468,14 +1472,16 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
AstNode *fake_ast = new AstNode(AST_NONE, clone(), children[0]->children.size() >= 2 ?
children[0]->children[1]->clone() : children[0]->children[0]->clone());
fake_ast->children[0]->delete_children();
if (member_node)
fake_ast->children[0]->attributes[ID::wiretype] = member_node->clone();
int fake_ast_width = 0;
bool fake_ast_sign = true;
fake_ast->children[1]->detectSignWidth(fake_ast_width, fake_ast_sign);
RTLIL::SigSpec shift_val = fake_ast->children[1]->genRTLIL(fake_ast_width, fake_ast_sign);
if (id2ast->range_right != 0) {
shift_val = current_module->Sub(NEW_ID, shift_val, id2ast->range_right, fake_ast_sign);
if (source_offset != 0) {
shift_val = current_module->Sub(NEW_ID, shift_val, source_offset, fake_ast_sign);
fake_ast->children[1]->is_signed = true;
}
if (id2ast->range_swapped) {
@ -1491,10 +1497,10 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
return sig;
} else {
chunk.width = children[0]->range_left - children[0]->range_right + 1;
chunk.offset = children[0]->range_right - source_offset;
chunk.offset += children[0]->range_right - source_offset;
if (id2ast->range_swapped)
chunk.offset = (id2ast->range_left - id2ast->range_right + 1) - (chunk.offset + chunk.width);
if (chunk.offset > item_left || chunk.offset + chunk.width < item_right) {
chunk.offset = source_width - (chunk.offset + chunk.width);
if (chunk.offset > chunk_left || chunk.offset + chunk.width < chunk_right) {
if (chunk.width == 1)
log_file_warning(filename, location.first_line, "Range select out of bounds on signal `%s': Setting result bit to undef.\n",
str.c_str());
@ -1503,12 +1509,12 @@ RTLIL::SigSpec AstNode::genRTLIL(int width_hint, bool sign_hint)
children[0]->range_left, children[0]->range_right, str.c_str(), chunk.width);
chunk = RTLIL::SigChunk(RTLIL::State::Sx, chunk.width);
} else {
if (chunk.offset + chunk.width - 1 > item_left) {
add_undef_bits_msb = (chunk.offset + chunk.width - 1) - item_left;
if (chunk.offset + chunk.width - 1 > chunk_left) {
add_undef_bits_msb = (chunk.offset + chunk.width - 1) - chunk_left;
chunk.width -= add_undef_bits_msb;
}
if (chunk.offset < item_right) {
add_undef_bits_lsb = item_right - chunk.offset;
if (chunk.offset < chunk_right) {
add_undef_bits_lsb = chunk_right - chunk.offset;
chunk.width -= add_undef_bits_lsb;
chunk.offset += add_undef_bits_lsb;
}

44
frontends/ast/simplify.cc
View file

@ -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);
}

3
tests/svtypes/struct_array.sv
View file

@ -12,15 +12,16 @@ module top;
s.a[2:1] = 16'h1234;
s.a[5] = 8'h42;
s.a[-1] = '0;
s.b = '1;
s.b[1:0] = '0;
end
always_comb assert(s==64'h4200_0012_3400_FFFC);
always_comb assert(s.a[0][3:-4]===8'h0x);
always_comb assert(s.b[23:16]===8'hxx);
always_comb assert(s.b[19:12]===8'hxf);
always_comb assert(s.a[0][3:-4]===8'h0x);
struct packed {
bit [7:0] [7:0] a; // 8 element packed array of bytes