Add support for anon types in FQN generation

This fixes a bug in the fully qualified name generation we encounter a
segment that has no name, such as when a proc is really a C++ lambda
expression, which internally generates an anonymous class to house the
function. In this case, we generate a unique name based on the DIE's
offset to serve as the segment's name.

3 files changed, 21 insertions, 3 deletions

diff --git a/src/dwarf2pdb.cpp b/src/dwarf2pdb.cpp
index 763be85..afd062e 100644
--- a/src/dwarf2pdb.cpp
+++ b/src/dwarf2pdb.cpp
@@ -735,13 +735,29 @@ void CV2PDB::formatFullyQualifiedProcName(const DWARF_InfoData* proc, char* buf,
 

 	// Format the parents in reverse order with :: operator in between.

 	for (int i = segments.size() - 1; i >= 0; --i) {

-		const int nameLen = strlen(segments[i]->name);

+		const char* name = segments[i]->name;

+		char nameBuf[64] = {};

+		int nameLen = 0;

+		if (!segments[i]->name) {

+			// This segment has no name. This could be because it is part of

+			// an anonymous class, which often happens for lambda expressions.

+			// Generate a unique anonymous name for it.

+			nameLen = sprintf_s(nameBuf, "[anon_%x]", segments[i]->entryOff);

+			if (nameLen < 0) {

+				// Formatting failed. Try a default name.

+				assert(false);  // crash in debug builds.

+				name = "[anon]";

+			}

+			name = nameBuf;

+		} else {

+			nameLen = strlen(name);

+		}

 		if (remain < nameLen) {

 			fprintf(stderr, "unable to fit full proc name: %s\n", proc->name);

 			return;

 		}

 

-		memcpy(p, segments[i]->name, nameLen);

+		memcpy(p, name, nameLen);

 

 		p += nameLen;

 		remain -= nameLen;

diff --git a/src/readDwarf.cpp b/src/readDwarf.cpp
index 9218f41..8e4ca4d 100644
--- a/src/readDwarf.cpp
+++ b/src/readDwarf.cpp
@@ -766,7 +766,7 @@ DWARF_InfoData* DIECursor::readNext(DWARF_InfoData* entry, bool stopAtNull)
 			return nullptr; // root of the tree does not have a null terminator, but we know the length

 

 		id.entryPtr = ptr;

-		entryOff = img->debug_info.sectOff(ptr);

+		entryOff = id.entryOff = img->debug_info.sectOff(ptr);

 		id.code = LEB128(ptr);

 

 		// If the previously scanned node claimed to have a child, this must be a valid DIE.

diff --git a/src/readDwarf.h b/src/readDwarf.h
index 06779c8..04afa38 100644
--- a/src/readDwarf.h
+++ b/src/readDwarf.h
@@ -191,6 +191,8 @@ struct DWARF_InfoData
 	// Pointer into the memory-mapped image section where this DIE is located.

 	byte* entryPtr;

 

+	unsigned int entryOff = 0;  // the entry offset in the section it is in.

+

 	// Code to find the abbrev entry for this DIE, or 0 if it a sentinel marking

 	// the end of a sibling chain.

 	int code;