[import] Use linker version script to avoid UNIQUE symbols

pymtl · Oct 25, 2023 · 3b57776 · 3b57776
1 parent 85b579d
commit 3b57776
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Showing 5 changed files with 44 additions and 7 deletions.
diff --git a/pymtl3/passes/backends/verilog/import_/VerilogVerilatorImportConfigs.py b/pymtl3/passes/backends/verilog/import_/VerilogVerilatorImportConfigs.py
@@ -333,6 +333,12 @@ def create_cc_cmd( s ):
     coverage = "-DVM_COVERAGE" if s.vl_coverage or \
                                   s.vl_line_coverage or \
                                   s.vl_toggle_coverage else ""
+
+    # PP: try not to introduce GNU unique symbols to the shared library.
+    linker_version_script_filename = "verilator_import_linker_version_script.lds"
+    dir_to_version_script = os.path.abspath(os.path.dirname(__file__))
+    ld_flags += f" -Wl,--version-script={os.path.join(dir_to_version_script, linker_version_script_filename)}"
+
     return f"g++ {c_flags} {c_include_path} {ld_flags}"\
            f" -o {out_file} {c_src_files} {ld_libs} {coverage}"
 

diff --git a/pymtl3/passes/backends/verilog/import_/test/VRegTrace.v b/pymtl3/passes/backends/verilog/import_/test/VRegTrace.v
@@ -14,6 +14,8 @@ module test_VRegTrace(
   logic [512*8-1:0] q_str;
   `VC_TRACE_BEGIN
   begin
+    // PP: we should not use $ system tasks because
+    // they seem to be generating segfaults at end of pytest??
     /* $display("q = %d\n", q); */
     $sformat(q_str, "%d", q);
     vc_trace.append_str( trace_str, "q = " );

diff --git a/pymtl3/passes/backends/verilog/import_/verilator_import_linker_version_script.lds b/pymtl3/passes/backends/verilog/import_/verilator_import_linker_version_script.lds
@@ -0,0 +1,11 @@
+VERS_0.1 {
+  global:
+    create_model;
+    destroy_model;
+    comb_eval;
+    seq_eval;
+    assert_en;
+    trace;
+  local:
+    *;
+};
diff --git a/pymtl3/passes/backends/verilog/import_/verilator_wrapper_c_template.py b/pymtl3/passes/backends/verilog/import_/verilator_wrapper_c_template.py
@@ -108,7 +108,8 @@
   m     = (V{component_name}_t *) malloc( sizeof(V{component_name}_t) );
   model = new V{vl_component_name}(context_ptr);
 
-  m->model = (void *) model;
+  m->model       = (void *) model;
+  m->context_ptr = context_ptr;
 
   // Enable tracing. We have added a feature where if the vcd_filename is
   // "" then we don't do any VCD dumping even if DUMP_VCD is true.
@@ -161,6 +162,7 @@
   #endif
 
   delete model;
+  delete m->context_ptr;
 
   free(m);
 
@@ -226,7 +228,6 @@
     // PP: now that we have generated the VCD we need to set CLK back to 0.
     // We need to dump VCD again to register this clock toggle.
     m->trace_time += {half_cycle_time};
-    g_main_time   += {half_cycle_time};
 
     #if HAS_CLK
     model->clk = 0;
@@ -253,7 +254,6 @@
 
     // update simulation time only on clock toggle
     m->trace_time += {half_cycle_time};
-    g_main_time   += {half_cycle_time};
 
   }}
   #endif
@@ -323,7 +323,7 @@
   assert( dut_scope );
   svSetScope( dut_scope );
 
-  model->line_trace( words );
+  V{vl_component_name}::line_trace( words );
 
   // Note that the way the line tracing works, the line tracing function
   // will store how the last character used in the line trace in the

diff --git a/pymtl3/passes/backends/verilog/import_/verilator_wrapper_py_template.py b/pymtl3/passes/backends/verilog/import_/verilator_wrapper_py_template.py
@@ -9,7 +9,10 @@
 normal PyMTL model. This template is based on PyMTL v2.
 """
 
+import copy
 import os
+import gc
+import weakref
 
 from cffi import FFI
 
@@ -77,32 +80,43 @@ def finalize( s ):
     you might need to call `imported_object.finalize()` at the end of each test
     to ensure correct behaviors.
     """
+    # print(f"In finalize() method of an instance of {{str(s.__class__)}}")
     assert s._finalization_count == 0,\
       'Imported component can only be finalized once!'
     s._finalization_count += 1
 
     # Clean up python side FFI references
-    del s._line_trace_str
+    s.ffi.release(s._line_trace_str)
+
+    s._convert_string = None
 
     s._ffi_inst.destroy_model( s._ffi_m )
     s.ffi.dlclose( s._ffi_inst )
 
     del s._ffi_inst
     del s.ffi
 
+    gc.collect()
+    # print("End of finalize()")
+
   def __del__( s ):
+    # print(f"In __del__() method of an instance of {{str(s.__class__)}}")
     if s._finalization_count == 0:
       s._finalization_count += 1
 
       # Clean up python side FFI references
-      del s._line_trace_str
+      s.ffi.release(s._line_trace_str)
+      s._convert_string = None
 
       s._ffi_inst.destroy_model( s._ffi_m )
       s.ffi.dlclose( s._ffi_inst )
 
       del s._ffi_inst
       del s.ffi
 
+      gc.collect()
+    # print("End of __del__")
+
   def construct( s, *args, **kwargs ):
     # Set up the VCD file name
     verilator_vcd_file = ""
@@ -123,9 +137,13 @@ def construct( s, *args, **kwargs ):
     s._ffi_m = s._ffi_inst.create_model( ffi_vl_vcd_file )
 
     # Buffer for line tracing
-    s._line_trace_str = s.ffi.new('char[512]')
+    line_trace_str = s.ffi.new('char[512]')
+    s._line_trace_str = line_trace_str
     s._convert_string = s.ffi.string
 
+    global_weakref_dict = weakref.WeakKeyDictionary()
+    global_weakref_dict[s] = (line_trace_str)
+
     # Use non-attribute varialbe to reduce CPython bytecode count
     _ffi_m = s._ffi_m
     _ffi_inst_comb_eval = s._ffi_inst.comb_eval