Exception-awareness for gnu_libstdcpp formatters ; Documentation update

git-svn-id: https://llvm.org/svn/llvm-project/llvdb/trunk@138236 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/examples/synthetic/gnu_libstdcpp.py b/examples/synthetic/gnu_libstdcpp.py
index b26503f..6b6eab6 100644
--- a/examples/synthetic/gnu_libstdcpp.py
+++ b/examples/synthetic/gnu_libstdcpp.py
@@ -1,11 +1,10 @@
 import re
 
 # C++ STL formatters for LLDB
-# These formatters are based upon the version of the STL that ships
-# with Mac OS X Snow Leopard 10.6.8 and OS X Lion 10.7.0
-# The STL implementation *might* change on other releases of Apple's
-# operating system and library infrastructure, and might be different on
-# other operating systems
+# These formatters are based upon the version of the GNU libstdc++
+# as it ships with Mac OS X 10.6.8 and 10.7.0
+# You are encouraged to look at the STL implementation for your platform
+# before relying on these formatters to do the right thing for your setup
 
 class StdListSynthProvider:
 
@@ -14,34 +13,45 @@
 		self.update()
 
 	def num_children(self):
-		next_val = self.next.GetValueAsUnsigned(0)
-		prev_val = self.prev.GetValueAsUnsigned(0)
-		# After a std::list has been initialized, both next and prev will be non-NULL
-		if next_val == 0 or prev_val == 0:
-			return 0
-		if next_val == self.node_address:
-			return 0
-		if next_val == prev_val:
-			return 1
-		size = 2
-		current = self.next
-		while current.GetChildMemberWithName('_M_next').GetValueAsUnsigned(0) != self.node_address:
-			size = size + 1
-			current = current.GetChildMemberWithName('_M_next')
-		return (size - 1)
+		try:
+			next_val = self.next.GetValueAsUnsigned(0)
+			prev_val = self.prev.GetValueAsUnsigned(0)
+			# After a std::list has been initialized, both next and prev will be non-NULL
+			if next_val == 0 or prev_val == 0:
+				return 0
+			if next_val == self.node_address:
+				return 0
+			if next_val == prev_val:
+				return 1
+			size = 2
+			current = self.next
+			while current.GetChildMemberWithName('_M_next').GetValueAsUnsigned(0) != self.node_address:
+				size = size + 1
+				current = current.GetChildMemberWithName('_M_next')
+			return (size - 1)
+		except:
+			return 0;
 
 	def get_child_index(self,name):
-		return int(name.lstrip('[').rstrip(']'))
+		try:
+			return int(name.lstrip('[').rstrip(']'))
+		except:
+			return -1
 
 	def get_child_at_index(self,index):
+		if index < 0:
+			return None;
 		if index >= self.num_children():
 			return None;
-		offset = index
-		current = self.next
-		while offset > 0:
-			current = current.GetChildMemberWithName('_M_next')
-			offset = offset - 1
-		return current.CreateChildAtOffset('['+str(index)+']',2*current.GetType().GetByteSize(),self.data_type)
+		try:
+			offset = index
+			current = self.next
+			while offset > 0:
+				current = current.GetChildMemberWithName('_M_next')
+				offset = offset - 1
+			return current.CreateChildAtOffset('['+str(index)+']',2*current.GetType().GetByteSize(),self.data_type)
+		except:
+			return None:
 
 	def extract_type_name(self,name):
 		self.type_name = name[16:]
@@ -59,17 +69,20 @@
 		self.type_name_nospaces = self.type_name.replace(", ", ",")
 
 	def update(self):
-		impl = self.valobj.GetChildMemberWithName('_M_impl')
-		node = impl.GetChildMemberWithName('_M_node')
-		self.extract_type_name(impl.GetType().GetName())
-		self.node_address = self.valobj.AddressOf().GetValueAsUnsigned(0)
-		self.next = node.GetChildMemberWithName('_M_next')
-		self.prev = node.GetChildMemberWithName('_M_prev')
-		self.data_type = node.GetTarget().FindFirstType(self.type_name)
-		# tries to fight against a difference in formatting type names between gcc and clang
-		if self.data_type.IsValid() == False:
-			self.data_type = node.GetTarget().FindFirstType(self.type_name_nospaces)
-		self.data_size = self.data_type.GetByteSize()
+		try:
+			impl = self.valobj.GetChildMemberWithName('_M_impl')
+			node = impl.GetChildMemberWithName('_M_node')
+			self.extract_type_name(impl.GetType().GetName())
+			self.node_address = self.valobj.AddressOf().GetValueAsUnsigned(0)
+			self.next = node.GetChildMemberWithName('_M_next')
+			self.prev = node.GetChildMemberWithName('_M_prev')
+			self.data_type = node.GetTarget().FindFirstType(self.type_name)
+			# tries to fight against a difference in formatting type names between gcc and clang
+			if self.data_type.IsValid() == False:
+				self.data_type = node.GetTarget().FindFirstType(self.type_name_nospaces)
+			self.data_size = self.data_type.GetByteSize()
+		except:
+			pass
 
 class StdVectorSynthProvider:
 
@@ -78,45 +91,59 @@
 		self.update()
 
 	def num_children(self):
-		start_val = self.start.GetValueAsUnsigned(0)
-		finish_val = self.finish.GetValueAsUnsigned(0)
-		end_val  = self.end.GetValueAsUnsigned(0)
-		# Before a vector has been constructed, it will contain bad values
-		# so we really need to be careful about the length we return since
-		# unitialized data can cause us to return a huge number. We need
-		# to also check for any of the start, finish or end of storage values
-		# being zero (NULL). If any are, then this vector has not been 
-		# initialized yet and we should return zero
+		try:
+			start_val = self.start.GetValueAsUnsigned(0)
+			finish_val = self.finish.GetValueAsUnsigned(0)
+			end_val  = self.end.GetValueAsUnsigned(0)
+			# Before a vector has been constructed, it will contain bad values
+			# so we really need to be careful about the length we return since
+			# unitialized data can cause us to return a huge number. We need
+			# to also check for any of the start, finish or end of storage values
+			# being zero (NULL). If any are, then this vector has not been 
+			# initialized yet and we should return zero
 
-		# Make sure nothing is NULL
-		if start_val == 0 or finish_val == 0 or end_val == 0:
-			return 0
-		# Make sure start is less than finish
-		if start_val >= finish_val:
-			return 0
-		# Make sure finish is less than or equal to end of storage
-		if finish_val > end_val:
-			return 0
+			# Make sure nothing is NULL
+			if start_val == 0 or finish_val == 0 or end_val == 0:
+				return 0
+			# Make sure start is less than finish
+			if start_val >= finish_val:
+				return 0
+			# Make sure finish is less than or equal to end of storage
+			if finish_val > end_val:
+				return 0
 
-		num_children = (finish_val-start_val)/self.data_size
-		return num_children
+			num_children = (finish_val-start_val)/self.data_size
+			return num_children
+		except:
+			return 0;
 
 	def get_child_index(self,name):
-		return int(name.lstrip('[').rstrip(']'))
+		try:
+			return int(name.lstrip('[').rstrip(']'))
+		except:
+			return -1
 
 	def get_child_at_index(self,index):
+		if index < 0:
+			return None;
 		if index >= self.num_children():
 			return None;
-		offset = index * self.data_size
-		return self.start.CreateChildAtOffset('['+str(index)+']',offset,self.data_type)
+		try:
+			offset = index * self.data_size
+			return self.start.CreateChildAtOffset('['+str(index)+']',offset,self.data_type)
+		except:
+			return None
 
 	def update(self):
-		impl = self.valobj.GetChildMemberWithName('_M_impl')
-		self.start = impl.GetChildMemberWithName('_M_start')
-		self.finish = impl.GetChildMemberWithName('_M_finish')
-		self.end = impl.GetChildMemberWithName('_M_end_of_storage')
-		self.data_type = self.start.GetType().GetPointeeType()
-		self.data_size = self.data_type.GetByteSize()
+		try:
+			impl = self.valobj.GetChildMemberWithName('_M_impl')
+			self.start = impl.GetChildMemberWithName('_M_start')
+			self.finish = impl.GetChildMemberWithName('_M_finish')
+			self.end = impl.GetChildMemberWithName('_M_end_of_storage')
+			self.data_type = self.start.GetType().GetPointeeType()
+			self.data_size = self.data_type.GetByteSize()
+		except:
+			pass
 
 
 class StdMapSynthProvider:
@@ -126,21 +153,24 @@
 		self.update()
 
 	def update(self):
-		self.Mt = self.valobj.GetChildMemberWithName('_M_t')
-		self.Mimpl = self.Mt.GetChildMemberWithName('_M_impl')
-		self.Mheader = self.Mimpl.GetChildMemberWithName('_M_header')
-		# from libstdc++ implementation of _M_root for rbtree
-		self.Mroot = self.Mheader.GetChildMemberWithName('_M_parent')
-		# the stuff into the tree is actually a std::pair<const key, value>
-		# life would be much easier if gcc had a coherent way to print out
-		# template names in debug info
-		self.expand_clang_type_name()
-		self.expand_gcc_type_name()
-		self.data_type = self.Mt.GetTarget().FindFirstType(self.clang_type_name)
-		if self.data_type.IsValid() == False:
-			self.data_type = self.Mt.GetTarget().FindFirstType(self.gcc_type_name)
-		self.data_size = self.data_type.GetByteSize()
-		self.skip_size = self.Mheader.GetType().GetByteSize()
+		try:
+			self.Mt = self.valobj.GetChildMemberWithName('_M_t')
+			self.Mimpl = self.Mt.GetChildMemberWithName('_M_impl')
+			self.Mheader = self.Mimpl.GetChildMemberWithName('_M_header')
+			# from libstdc++ implementation of _M_root for rbtree
+			self.Mroot = self.Mheader.GetChildMemberWithName('_M_parent')
+			# the stuff into the tree is actually a std::pair<const key, value>
+			# life would be much easier if gcc had a coherent way to print out
+			# template names in debug info
+			self.expand_clang_type_name()
+			self.expand_gcc_type_name()
+			self.data_type = self.Mt.GetTarget().FindFirstType(self.clang_type_name)
+			if self.data_type.IsValid() == False:
+				self.data_type = self.Mt.GetTarget().FindFirstType(self.gcc_type_name)
+			self.data_size = self.data_type.GetByteSize()
+			self.skip_size = self.Mheader.GetType().GetByteSize()
+		except:
+			pass
 
 	def expand_clang_type_name(self):
 		type_name = self.Mimpl.GetType().GetName()
@@ -180,24 +210,35 @@
 		self.gcc_type_name = type_name
 
 	def num_children(self):
-		root_ptr_val = self.node_ptr_value(self.Mroot)
-		if root_ptr_val == 0:
+		try:
+			root_ptr_val = self.node_ptr_value(self.Mroot)
+			if root_ptr_val == 0:
+				return 0;
+			return self.Mimpl.GetChildMemberWithName('_M_node_count').GetValueAsUnsigned(0)
+		except:
 			return 0;
-		return self.Mimpl.GetChildMemberWithName('_M_node_count').GetValueAsUnsigned(0)
 
 	def get_child_index(self,name):
-		return int(name.lstrip('[').rstrip(']'))
+		try:
+			return int(name.lstrip('[').rstrip(']'))
+		except:
+			return -1
 
 	def get_child_at_index(self,index):
+		if index < 0:
+			return None
 		if index >= self.num_children():
 			return None;
-		offset = index
-		current = self.left(self.Mheader);
-		while offset > 0:
-			current = self.increment_node(current)
-			offset = offset - 1;
-		# skip all the base stuff and get at the data
-		return current.CreateChildAtOffset('['+str(index)+']',self.skip_size,self.data_type)
+		try:
+			offset = index
+			current = self.left(self.Mheader);
+			while offset > 0:
+				current = self.increment_node(current)
+				offset = offset - 1;
+			# skip all the base stuff and get at the data
+			return current.CreateChildAtOffset('['+str(index)+']',self.skip_size,self.data_type)
+		except:
+			return None
 
 	# utility functions
 	def node_ptr_value(self,node):