Fix classes/modules of case-similar names (#5109).

Changes

@@ -22,6 +22,7 @@ Verilator 5.027 devel
 * Add `--compiler-include` for additional C++ includes (#5139) (#5202). [Bartłomiej Chmiel, Antmicro Ltd.]
 * Add `--emit-accessors` (#5182) (#5227). [Ryan Ziegler]
 * Fix fusing macro arguments to not ignore whitespace (#5061). [Tudor Timi]
+* Fix classes/modules of case-similar names (#5109). [Arkadiusz Kozdra]
 * Fix mis-removing $value$plusargs calls (#5127) (#5137). [Seth Pellegrino]
 * Fix splitting if statements with impure conditions (#5219). [Bartłomiej Chmiel, Antmicro Ltd.]
 * Fix unknown conversion on queues (#5220). [Alex Solomatnikov]

src/V3EmitCBase.cpp

@@ -35,6 +35,42 @@ EmitCParentModule::EmitCParentModule() {
     setAll(v3Global.rootp()->constPoolp()->modp());
 }
 
+//######################################################################
+// EmitCBase implementation
+
+string EmitCBase::prefixNameProtect(const AstNode* nodep) VL_MT_STABLE {
+    const string prefix = v3Global.opt.modPrefix() + "_" + VIdProtect::protect(nodep->name());
+    // If all-uppercase prefix conflicts with a previous usage of the
+    // prefix with different capitalization, rename to avoid conflict.
+    // This is to support OSes where filename compares are non-case significant.
+    // STATIC:
+    static V3Mutex s_mutex;
+    const V3LockGuard lock{s_mutex};  // Otherwise map access is unsafe
+    static std::map<std::string, std::string> s_memoized;
+    static std::map<std::string, std::string> s_ucToPrefix;
+    // Memoize results
+    const auto mit = s_memoized.find(prefix);
+    if (mit != s_memoized.end()) return mit->second;
+    //
+    // Check capitalization
+    const string prefixUpper = VString::upcase(prefix);
+    string result;
+    {
+        const auto it = s_ucToPrefix.find(prefixUpper);
+        if (it == s_ucToPrefix.end()) {
+            s_ucToPrefix.emplace(prefixUpper, prefix);
+            result = prefix;
+        } else if (it->second == prefix) {
+            result = prefix;  // Same capitialization as last time
+        } else {
+            VHashSha256 hash{prefix};
+            result = prefix + "__Vphsh" + hash.digestSymbol();
+        }
+    }
+    s_memoized.emplace(prefix, result);
+    return result;
+}
+
 //######################################################################
 // EmitCBaseVisitor implementation
 

src/V3EmitCBase.h

@@ -66,9 +66,8 @@ public:
     static string topClassName() VL_MT_SAFE {  // Return name of top wrapper module
         return v3Global.opt.prefix();
     }
-    static string prefixNameProtect(const AstNode* nodep) VL_MT_STABLE {  // C++ name with prefix
-        return v3Global.opt.modPrefix() + "_" + VIdProtect::protect(nodep->name());
-    }
+    // Return C++ class name for a module/class object
+    static string prefixNameProtect(const AstNode* nodep) VL_MT_STABLE;
     static bool isAnonOk(const AstVar* varp) {
         AstNodeDType* const dtp = varp->dtypep()->skipRefp();
         return v3Global.opt.compLimitMembers() != 0  // Enabled

test_regress/t/t_class_capitalization.pl

@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2024 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;

test_regress/t/t_class_capitalization.v

@@ -0,0 +1,64 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2024 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+// Test different uppercase/lowercase capitalization cases
+class ClsMixed;
+   int m;
+   int M;
+endclass
+
+class Clsmixed;
+   int m;
+   int M;
+endclass
+
+module ModMixed;
+   // verilator no_inline_module
+   int m;
+   int M;
+endmodule
+
+module Modmixed;
+   // verilator no_inline_module
+   int m;
+   int M;
+endmodule
+
+module t(/*AUTOARG*/);
+   // verilator no_inline_module
+
+   ModMixed modMixed();
+   Modmixed modmixed();
+
+   initial begin
+      ClsMixed clsMixed;
+      Clsmixed clsmixed;
+
+      clsMixed = new;
+      clsMixed.m = 1;
+      clsMixed.M = 2;
+      clsmixed = new;
+      clsmixed.m = 3;
+      clsmixed.M = 4;
+      if (clsMixed.m != 1) $stop;
+      if (clsMixed.M != 2) $stop;
+      if (clsmixed.m != 3) $stop;
+      if (clsmixed.M != 4) $stop;
+
+      modMixed.m = 1;
+      modMixed.M = 2;
+      modmixed.m = 3;
+      modmixed.M = 4;
+      if (modMixed.m != 1) $stop;
+      if (modMixed.M != 2) $stop;
+      if (modmixed.m != 3) $stop;
+      if (modmixed.M != 4) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule