ecp5: Proof-of-concept using IdStringList for bel names

This uses the new IdStringList API to store bel names for the ECP5. Note
that other arches and the GUI do not yet build with this
proof-of-concept patch.

getBelByName still uses the old implementation and could be more
efficiently implemented with further development.

Signed-off-by: D. Shah <dave@ds0.me>

1 files changed, 22 insertions, 4 deletions

diff --git a/common/nextpnr.h b/common/nextpnr.h
index 66f31867..9523e418 100644
--- a/common/nextpnr.h
+++ b/common/nextpnr.h
@@ -148,14 +148,13 @@ NEXTPNR_NAMESPACE_BEGIN
 // An small size optimised array that is statically allocated when the size is N or less; heap allocated otherwise
 template <typename T, size_t N> class SSOArray
 {
+  private:
     union
     {
         T data_static[N];
         T *data_heap;
     };
     size_t m_size;
-
-  private:
     inline bool is_heap() const { return (m_size > N); }
     void alloc()
     {
@@ -224,8 +223,8 @@ struct IdStringList
     SSOArray<IdString, 4> ids;
 
     IdStringList(){};
-    explicit IdStringList(size_t n) : ids(n, IdString()){};
-    explicit IdStringList(IdString id) : ids(1, id){};
+    IdStringList(size_t n) : ids(n, IdString()){};
+    IdStringList(IdString id) : ids(1, id){};
     template <typename Tlist> IdStringList(const Tlist &list) : ids(list){};
 
     static IdStringList parse(Context *ctx, const std::string &str);
@@ -238,6 +237,19 @@ struct IdStringList
     const IdString &operator[](size_t idx) const { return ids[idx]; }
 };
 
+// A ring buffer of strings, so we can return a simple const char * pointer for %s formatting - inspired by how logging
+// in Yosys works Let's just hope noone tries to log more than 100 things in one call....
+class StrRingBuffer
+{
+  private:
+    static const size_t N = 100;
+    std::array<std::string, N> buffer;
+    size_t index = 0;
+
+  public:
+    std::string &next();
+};
+
 struct GraphicElement
 {
     enum type_t
@@ -760,6 +772,9 @@ struct BaseCtx
     mutable std::unordered_map<std::string, int> *idstring_str_to_idx;
     mutable std::vector<const std::string *> *idstring_idx_to_str;
 
+    // Temporary string backing store for logging
+    mutable StrRingBuffer log_strs;
+
     // Project settings and config switches
     std::unordered_map<IdString, Property> settings;
 
@@ -875,6 +890,9 @@ struct BaseCtx
     const char *nameOfPip(PipId pip) const;
     const char *nameOfGroup(GroupId group) const;
 
+    // Overrides of arch functions that take a string and handle IdStringList parsing
+    BelId getBelByNameStr(const std::string &str);
+
     // --------------------------------------------------------------
 
     bool allUiReload = true;