[llvm-readelf] Support dumping of stack sizes sections with readelf --stack-sizes

Reviewers: jhenderson, grimar, rupprecht

Differential Revision: https://reviews.llvm.org/D65313

llvm-svn: 367942
diff --git a/llvm/docs/CommandGuide/llvm-readelf.rst b/llvm/docs/CommandGuide/llvm-readelf.rst
index 0faad07..ecdb8f8 100644
--- a/llvm/docs/CommandGuide/llvm-readelf.rst
+++ b/llvm/docs/CommandGuide/llvm-readelf.rst
@@ -160,6 +160,11 @@
 
  Display contents of the stackmap section.
 
+.. option:: --stack-sizes
+
+ Display the contents of the stack sizes section(s), i.e. pairs of function
+ names and the size of their stack frames.
+
 .. option:: --string-dump=<section[,section,...]>, -p
 
  Display the specified section(s) as a list of strings. ``section`` may be a