1 files changed, 64 insertions, 0 deletions
diff --git a/llvm/utils/gdb-scripts/prettyprinters.py b/llvm/utils/gdb-scripts/prettyprinters.py
index cf1c96a449e..5385e16246b 100644
--- a/llvm/utils/gdb-scripts/prettyprinters.py
+++ b/llvm/utils/gdb-scripts/prettyprinters.py
@@ -131,10 +131,74 @@ class OptionalPrinter:
   def to_string(self):
     return 'llvm::Optional is %sinitialized' % ('' if self.value['hasVal'] else 'not ')
 
+class DenseMapPrinter:
+  "Print a DenseMap"
+
+  class _iterator:
+    def __init__(self, key_info_t, begin, end):
+      self.key_info_t = key_info_t
+      self.cur = begin
+      self.end = end
+      self.advancePastEmptyBuckets()
+      self.first = True
+
+    def __iter__(self):
+      return self
+
+    def advancePastEmptyBuckets(self):
+      # disabled until the comments below can be addressed
+      # keeping as notes/posterity/hints for future contributors
+      return
+      n = self.key_info_t.name
+      is_equal = gdb.parse_and_eval(n + '::isEqual')
+      empty = gdb.parse_and_eval(n + '::getEmptyKey()')
+      tombstone = gdb.parse_and_eval(n + '::getTombstoneKey()')
+      # the following is invalid, GDB fails with:
+      #   Python Exception <class 'gdb.error'> Attempt to take address of value
+      #   not located in memory.
+      # because isEqual took parameter (for the unsigned long key I was testing)
+      # by const ref, and GDB
+      # It's also not entirely general - we should be accessing the "getFirst()"
+      # member function, not the 'first' member variable, but I've yet to figure
+      # out how to find/call member functions (especially (const) overloaded
+      # ones) on a gdb.Value.
+      while self.cur != self.end and (is_equal(self.cur.dereference()['first'], empty) or is_equal(self.cur.dereference()['first'], tombstone)):
+        self.cur = self.cur + 1
+
+    def next(self):
+      if self.cur == self.end:
+        raise StopIteration
+      cur = self.cur
+      v = cur.dereference()['first' if self.first else 'second']
+      if not self.first:
+        self.cur = self.cur + 1
+        self.advancePastEmptyBuckets()
+        self.first = True
+      else:
+        self.first = False
+      return 'x', v
+
+  def __init__(self, val):
+    self.val = val
+
+  def children(self):
+    t = self.val.type.template_argument(3).pointer()
+    begin = self.val['Buckets'].cast(t)
+    end = (begin + self.val['NumBuckets']).cast(t)
+    return self._iterator(self.val.type.template_argument(2), begin, end)
+
+  def to_string(self):
+    return 'llvm::DenseMap with %d elements' % (self.val['NumEntries'])
+
+  def display_hint(self):
+    return 'map'
+
+
 pp = gdb.printing.RegexpCollectionPrettyPrinter("LLVMSupport")
 pp.add_printer('llvm::SmallString', '^llvm::SmallString<.*>$', SmallStringPrinter)
 pp.add_printer('llvm::StringRef', '^llvm::StringRef$', StringRefPrinter)
 pp.add_printer('llvm::SmallVectorImpl', '^llvm::SmallVector(Impl)?<.*>$', SmallVectorPrinter)
 pp.add_printer('llvm::ArrayRef', '^llvm::(Const)?ArrayRef<.*>$', ArrayRefPrinter)
 pp.add_printer('llvm::Optional', '^llvm::Optional<.*>$', OptionalPrinter)
+pp.add_printer('llvm::DenseMap', '^llvm::DenseMap<.*>$', DenseMapPrinter)
 gdb.printing.register_pretty_printer(gdb.current_objfile(), pp)