From 6ee0d135e6abfd21c6fd3ba8c5da1133b10a69d3 Mon Sep 17 00:00:00 2001
From: Johannes Sixt <j6t@kdbg.org>
Date: Sat, 17 Sep 2016 19:22:56 +0200
Subject: [PATCH] Handle pointer-to-member function values that are virtual
 functions.

A pointer-to-member function can hold a pointer to a virtual member
function. Parse such a value.
---
 kdbg/gdbdriver.cpp            | 65 +++++++++++++++++++++++++++++++++++++++----
 kdbg/testprogs/multibrkpt.cpp |  9 ++++++
 kdbg/testprogs/testfile.cpp   |  5 +++-
 3 files changed, 72 insertions(+), 7 deletions(-)

diff --git a/kdbg/gdbdriver.cpp b/kdbg/gdbdriver.cpp
index e4234c6..cdd5009 100644
--- a/kdbg/gdbdriver.cpp
+++ b/kdbg/gdbdriver.cpp
@@ -1171,13 +1171,53 @@ static void skipNestedWithString(const char*& s, char opening, char closing)
     s = p;
 }
 
-inline void skipName(const char*& p)
+static void skipName(const char*& p)
 {
     // allow : (for enumeration values) and $ and . (for _vtbl.)
     while (isalnum(*p) || *p == '_' || *p == ':' || *p == '$' || *p == '.')
 	p++;
 }
 
+static void skipFunctionName(const char*& p)
+{
+    while (*p)
+    {
+	if (*p == '<') {
+	    // skip template parameter list
+	    skipNestedAngles(p);
+	} else if (*p == '(') {
+	    // this skips "(anonymous namespace)" as well as the formal
+	    // parameter list of the containing function if this is a member
+	    // of a nested class
+	    skipNestedWithString(p, '(', ')');
+	} else if (isalnum(*p) || *p == '_' || *p == ':') {
+	    const char* start = p;
+	    skipName(p);
+	    // check for operator
+	    if (p-start >= 8 &&
+		strncmp(p-8, "operator", 8) == 0 &&
+		// do  not mistake this as the tail of some identifier
+		(p-start == 8 || !(isalnum(p[-9]) || p[-9] == '_')))
+	    {
+		// skip forward until we find the opening parenthesis
+		// this catches both operator()(...) as well as
+		// type conversion operators, e.g.
+		//  operator char const*() const
+		//  operator void(*)()
+		while (*p && *p != '(')
+		    p++;
+	    }
+	} else if (strncmp(p, " const", 6) == 0 &&
+		    // must not mistake "const" as the beginning of
+		    // a subequent identifier
+		    !isalnum(p[6]) &&  p[6] != '_') {
+	    p += 6;
+	} else {
+	    break;
+	}
+    }
+}
+
 static bool parseName(const char*& s, QString& name, VarTree::NameKind& kind)
 {
     kind = VarTree::NKplain;
@@ -1283,6 +1323,8 @@ repeat:
 	//  (E *) 0xbffff450
 	//  red
 	//  &parseP (HTMLClueV *, char *)
+	//  &virtual table offset 0, this adjustment 140737488346016
+	//  &virtual Dl::operator char const*() const
 	//  Variable "x" is not available.
 	//  The value of variable 'x' is distributed...
 	//  -nan(0xfffff081defa0)
@@ -1373,12 +1415,23 @@ repeat:
 	    checkMultiPart = p[1] == '\'';
 	    skipString(p);
 	} else if (*p == '&') {
-	    // function pointer
 	    p++;
-	    skipName(p);
-	    skipSpace(p);
-	    if (*p == '(') {
-		skipNested(p, '(', ')');
+	    if (strncmp(p, "virtual ", 8) == 0) {
+		p += 8;
+		if (strncmp(p, "table offset ", 13) == 0) {
+		    p += 13;
+		    skipDecimal(p);
+		    checkMultiPart = true;
+		} else {
+		    skipFunctionName(p);
+		}
+	    } else {
+		// function pointer
+		skipName(p);
+		skipSpace(p);
+		if (*p == '(') {
+		    skipNested(p, '(', ')');
+		}
 	    }
 	} else if (strncmp(p, "Variable \"", 10) == 0) {
 	    // Variable "x" is not available.
diff --git a/kdbg/testprogs/multibrkpt.cpp b/kdbg/testprogs/multibrkpt.cpp
index d2d15ba..7a71885 100644
--- a/kdbg/testprogs/multibrkpt.cpp
+++ b/kdbg/testprogs/multibrkpt.cpp
@@ -14,6 +14,9 @@ struct Templated
 	void PrintV() {
 		cout << __func__ << " val=" << val << endl;
 	}
+	virtual void PrintName(int,int) const {
+		cout << __func__ << endl;
+	}
 };
 
 struct MostDerived : Templated<int>, Templated<double>
@@ -28,6 +31,9 @@ struct MostDerived : Templated<int>, Templated<double>
 		Templated<int>::PrintV();
 		Templated<double>::PrintV();
 	}
+	virtual void PrintName(int,int) const {
+		cout << __func__ << endl;
+	}
 };
 
 int main()
@@ -38,10 +44,13 @@ int main()
 	void (Templated<int>::*pmf1)();
 	void (Templated<double>::*pmf2)();
 	void (MostDerived::*pmf3)();
+	void (MostDerived::*pmf4)(int,int) const;
 	pmf1 = static_cast<void (Templated<int>::*)()>(&MostDerived::PrintV);
 	// the following has a non-trivial "this adjustment"
 	pmf2 = static_cast<void (Templated<double>::*)()>(&MostDerived::PrintV);
 	pmf3 = &Templated<double>::PrintV;
+	pmf4 = &Templated<double>::PrintName;
 
 	bothobj.PrintV();
+	(bothobj.*pmf4)(2, -5);
 }
diff --git a/kdbg/testprogs/testfile.cpp b/kdbg/testprogs/testfile.cpp
index 18b9ab5..e747c37 100644
--- a/kdbg/testprogs/testfile.cpp
+++ b/kdbg/testprogs/testfile.cpp
@@ -38,9 +38,10 @@ public:
 	Dl(int r);
 	virtual int f(int x);
 	int operator()(const QString& x, int& y) const;
-	operator const char*() { return 0; }
+	virtual operator const char*() const { return 0; }
 	operator PtrFunc*();
 	void takeACStr(const char* cstr);
+	double m;
 };
 
 namespace A {
@@ -185,6 +186,8 @@ int main(int argc, char* argv[])
 	int n = 83;
 	d1(strref, n);
 	PtrFunc* ppf = d1;
+	const char* (Dl::*pmf)() const = &Dl::operator const char*;
+	double (Dl::*pmv) = &Dl::m;
 	d1.takeACStr(globarstr);
 }
 
-- 
2.11.4.GIT