From dc306cf371bd5ece54d3965ca7a9938f957ca6ad Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 24 Nov 2020 18:35:12 -0500
Subject: [PATCH] Internal debug: avoid segflt with gdb "pnt"

---
 src/.gdbinit  |  6 +++---
 src/V3Ast.cpp | 48 ++++++++++++++++++++++++++++++------------------
 src/V3Ast.h   |  6 +++---
 3 files changed, 36 insertions(+), 24 deletions(-)

diff --git a/src/.gdbinit b/src/.gdbinit
index 17532d0d2..8e973680f 100644
--- a/src/.gdbinit
+++ b/src/.gdbinit
@@ -7,21 +7,21 @@
 # SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 
 define pn
-  call $arg0->dumpGdb()
+  call AstNode::dumpGdb($arg0)
 end
 document pn
   Verilator: Print single AstNode NODEP
 end
 
 define pnt
-  call $arg0->dumpTreeGdb()
+  call AstNode::dumpTreeGdb($arg0)
 end
 document pnt
   Verilator: Print AstNode NODEP's tree
 end
 
 define dtf
-  call AstNode::dumpTreeFileGdb(0)
+  call AstNode::dumpTreeFileGdb($arg0, 0)
 end
 document dtf
   Verilator: Dump AstNode tree to file
diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 234dd49d9..9e2b9843b 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -1029,28 +1029,40 @@ void AstNode::checkTree() {
 }
 
 // cppcheck-suppress unusedFunction  // Debug only
-void AstNode::dumpGdb() {  // For GDB only  // LCOV_EXCL_LINE
-    dumpGdbHeader();  // LCOV_EXCL_LINE
+void AstNode::dumpGdb(const AstNode* nodep) {  // For GDB only  // LCOV_EXCL_LINE
+    if (!nodep) {
+        cout << "<nullptr>" << endl;
+        return;
+    }
+    nodep->dumpGdbHeader();
     cout << "  ";
-    dump(cout);
-    cout << endl;  // LCOV_EXCL_LINE
-}
+    nodep->dump(cout);
+    cout << endl;
+}  // LCOV_EXCL_STOP
 // cppcheck-suppress unusedFunction  // Debug only
-void AstNode::dumpGdbHeader() const {  // For GDB only  // LCOV_EXCL_LINE
-    dumpPtrs(cout);  // LCOV_EXCL_LINE
-    cout << "  Fileline = " << fileline() << endl;  // LCOV_EXCL_LINE
-}
+void AstNode::dumpGdbHeader() const {  // For GDB only  // LCOV_EXCL_START
+    dumpPtrs(cout);
+    cout << "  Fileline = " << fileline() << endl;
+}  // LCOV_EXCL_STOP
 // cppcheck-suppress unusedFunction  // Debug only
-void AstNode::dumpTreeGdb() {  // For GDB only  // LCOV_EXCL_LINE
-    dumpGdbHeader();  // LCOV_EXCL_LINE
-    dumpTree(cout);  // LCOV_EXCL_LINE
-}
+void AstNode::dumpTreeGdb(const AstNode* nodep) {  // For GDB only  // LCOV_EXCL_START
+    if (!nodep) {
+        cout << "<nullptr>" << endl;
+        return;
+    }
+    nodep->dumpGdbHeader();
+    nodep->dumpTree(cout);
+}  // LCOV_EXCL_STOP
 // cppcheck-suppress unusedFunction  // Debug only
-void AstNode::dumpTreeFileGdb(const char* filenamep) {  // For GDB only  // LCOV_EXCL_LINE
-    string filename
-        = filenamep ? filenamep : v3Global.debugFilename("debug.tree", 98);  // LCOV_EXCL_LINE
-    v3Global.rootp()->dumpTreeFile(filename);  // LCOV_EXCL_LINE
-}
+void AstNode::dumpTreeFileGdb(const AstNode* nodep,  // LCOV_EXCL_START
+                              const char* filenamep) {  // For GDB only
+    if (!nodep) {
+        cout << "<nullptr>" << endl;
+        return;
+    }
+    string filename = filenamep ? filenamep : v3Global.debugFilename("debug.tree", 98);
+    v3Global.rootp()->dumpTreeFile(filename);
+}  // LCOV_EXCL_STOP
 
 // cppcheck-suppress unusedFunction  // Debug only
 void AstNode::checkIter() const {
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 5326f1515..01ff69a85 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -1761,7 +1761,7 @@ public:
     string warnOther() const { return fileline()->warnOther(); }
 
     virtual void dump(std::ostream& str = std::cout) const;
-    void dumpGdb();  // For GDB only
+    static void dumpGdb(const AstNode* nodep);  // For GDB only
     void dumpGdbHeader() const;
 
     // METHODS - Tree modifications
@@ -1811,12 +1811,12 @@ public:
     void dumpTree(const string& indent, int maxDepth = 0) const {
         dumpTree(cout, indent, maxDepth);
     }
-    void dumpTreeGdb();  // For GDB only
+    static void dumpTreeGdb(const AstNode* nodep);  // For GDB only
     void dumpTreeAndNext(std::ostream& os = std::cout, const string& indent = "    ",
                          int maxDepth = 0) const;
     void dumpTreeFile(const string& filename, bool append = false, bool doDump = true,
                       bool doCheck = true);
-    static void dumpTreeFileGdb(const char* filenamep = nullptr);
+    static void dumpTreeFileGdb(const AstNode* nodep, const char* filenamep = nullptr);
 
     // METHODS - queries
     // Changes control flow, disable some optimizations