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Handle range offsets in packed arrays within packed structs

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This brings the metadata for packed arrays in packed structs
in line with the metadata for unpacked arrays, and correctly
handles the case when both lsb and msb in an address range are
non-zero.
This commit is contained in:
Dag Lem 2023-02-05 11:01:37 +01:00
parent 26db5a11d3
commit 777c589e85
2 changed files with 51 additions and 22 deletions
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53
frontends/ast/simplify.cc
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@ -278,17 +278,21 @@ static int range_width(AstNode *node, AstNode *rnode)
log_file_error(node->filename, node->location.first_line, "Unpacked array in packed struct/union member %s\n", node->str.c_str());
}
static void save_struct_array_width(AstNode *node, int width)
static void save_struct_range_dimensions(AstNode *node, AstNode *rnode)
{
// stash the stride for the array
node->multirange_dimensions.push_back(width);
node->multirange_dimensions.push_back(rnode->range_right);
node->multirange_dimensions.push_back(range_width(node, rnode));
node->multirange_swapped.push_back(rnode->range_swapped);
}
static void save_struct_range_swapped(AstNode *node, bool range_swapped)
static int get_struct_range_offset(AstNode *node, int dimension)
{
node->multirange_swapped.push_back(range_swapped);
return node->multirange_dimensions[2*dimension];
}
static int get_struct_range_width(AstNode *node, int dimension)
{
return node->multirange_dimensions[2*dimension + 1];
}
static int size_packed_struct(AstNode *snode, int base_offset)
@ -322,14 +326,17 @@ static int size_packed_struct(AstNode *snode, int base_offset)
if (node->children[1]->type == AST_RANGE) {
// Unpacked array, e.g. bit [63:0] a [0:3]
auto rnode = node->children[1];
// C-style array size, e.g. bit [63:0] a [4]
bool c_type = rnode->children.size() == 1;
int array_count = c_type ? rnode->range_left : range_width(node, rnode);
save_struct_array_width(node, array_count);
save_struct_range_swapped(node, rnode->range_swapped || c_type);
save_struct_array_width(node, width);
save_struct_range_swapped(node, node->children[0]->range_swapped);
width *= array_count;
if (rnode->children.size() == 1) {
// C-style array size, e.g. bit [63:0] a [4]
node->multirange_dimensions.push_back(0);
node->multirange_dimensions.push_back(rnode->range_left);
node->multirange_swapped.push_back(true);
width *= rnode->range_left;
} else {
save_struct_range_dimensions(node, rnode);
width *= range_width(node, rnode);
}
save_struct_range_dimensions(node, node->children[0]);
}
else {
// The Yosys extension for unpacked arrays in packed structs / unions
@ -338,8 +345,7 @@ static int size_packed_struct(AstNode *snode, int base_offset)
}
} else {
// Vector
save_struct_array_width(node, width);
save_struct_range_swapped(node, node->children[0]->range_swapped);
save_struct_range_dimensions(node, node->children[0]);
}
// range nodes are now redundant
for (AstNode *child : node->children)
@ -355,10 +361,8 @@ static int size_packed_struct(AstNode *snode, int base_offset)
}
width = 1;
for (auto rnode : node->children[0]->children) {
int rwidth = range_width(node, rnode);
save_struct_array_width(node, rwidth);
save_struct_range_swapped(node, rnode->range_swapped);
width *= rwidth;
save_struct_range_dimensions(node, rnode);
width *= range_width(node, rnode);
}
// range nodes are now redundant
for (AstNode *child : node->children)
@ -422,9 +426,14 @@ static AstNode *normalize_struct_index(AstNode *expr, AstNode *member_node, int
{
expr = expr->clone();
int offset = get_struct_range_offset(member_node, dimension);
if (offset) {
expr = new AstNode(AST_SUB, expr, node_int(offset));
}
if (member_node->multirange_swapped[dimension]) {
// The dimension has swapped range; swap index into the struct accordingly.
int msb = member_node->multirange_dimensions[dimension] - 1;
int msb = get_struct_range_width(member_node, dimension) - 1;
expr = new AstNode(AST_SUB, node_int(msb), expr);
}
@ -433,7 +442,7 @@ static AstNode *normalize_struct_index(AstNode *expr, AstNode *member_node, int
static AstNode *struct_index_lsb_offset(AstNode *lsb_offset, AstNode *rnode, AstNode *member_node, int dimension, int &stride)
{
stride /= member_node->multirange_dimensions[dimension];
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);