Adding an unique id to Instruction generated by IRContext

Each instruction is given an unique id that can be used for ordering
purposes. The ids are generated via the IRContext.

Major changes:
* Instructions now contain a uint32_t for unique id and a cached context
pointer
 * Most constructors have been modified to take a context as input
 * unfortunately I cannot remove the default and copy constructors, but
 developers should avoid these
* Added accessors to parents of basic block and function
* Removed the copy constructors for BasicBlock and Function and replaced
them with Clone functions
* Reworked BuildModule to return an IRContext owning the built module
 * Since all instructions require a context, the context now becomes the
basic unit for IR
* Added a constructor to context to create an owned module internally
* Replaced uses of Instruction's copy constructor with Clone whereever I
found them
* Reworked the linker functionality to perform clones into a different
context instead of moves
* Updated many tests to be consistent with the above changes
 * Still need to add new tests to cover added functionality
* Added comparison operators to Instruction
* Added an internal option to LinkerOptions to verify merged ids are
unique
* Added a test for the linker to verify merged ids are unique

* Updated MergeReturnPass to supply a context
* Updated DecorationManager to supply a context for cloned decorations

* Reworked several portions of the def use tests in anticipation of next
set of changes

1 files changed, 15 insertions, 1 deletions

diff --git a/include/spirv-tools/linker.hpp b/include/spirv-tools/linker.hpp
index 43c725da..a36aa75f 100644
--- a/include/spirv-tools/linker.hpp
+++ b/include/spirv-tools/linker.hpp
@@ -26,7 +26,9 @@ namespace spvtools {
 
 class LinkerOptions {
  public:
-  LinkerOptions() : createLibrary_(false) {}
+  LinkerOptions()
+      : createLibrary_(false),
+        verifyIds_(false) {}
 
   // Returns whether a library or an executable should be produced by the
   // linking phase.
@@ -36,13 +38,25 @@ class LinkerOptions {
   // The returned value will be true if creating a library, and false if
   // creating an executable.
   bool GetCreateLibrary() const { return createLibrary_; }
+
   // Sets whether a library or an executable should be produced.
   void SetCreateLibrary(bool create_library) {
     createLibrary_ = create_library;
   }
 
+  // Returns whether to verify the uniqueness of the unique ids in the merged
+  // context.
+  bool GetVerifyIds() const { return verifyIds_; }
+
+  // Sets whether to verify the uniqueness of the unique ids in the merged
+  // context.
+  void SetVerifyIds(bool verifyIds) {
+    verifyIds_ = verifyIds;
+  }
+
  private:
   bool createLibrary_;
+  bool verifyIds_;
 };
 
 class Linker {