[CodeGen] Move printing MO_CFIIndex operands to MachineOperand::print

Work towards the unification of MIR and debug output by refactoring the
interfaces.

Before this patch we printed "<call frame instruction>" in the debug
output.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321084 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 21 insertions, 1 deletions

diff --git a/docs/MIRLangRef.rst b/docs/MIRLangRef.rst
index f170c721087..541c024bdec 100644
--- a/docs/MIRLangRef.rst
+++ b/docs/MIRLangRef.rst
@@ -692,6 +692,27 @@ The syntax is:
 
     EH_LABEL <mcsymbol Ltmp1>
 
+CFIIndex Operands
+^^^^^^^^^^^^^^^^^
+
+A CFI Index operand is holding an index into a per-function side-table,
+``MachineFunction::getFrameInstructions()``, which references all the frame
+instructions in a ``MachineFunction``. A ``CFI_INSTRUCTION`` may look like it
+contains multiple operands, but the only operand it contains is the CFI Index.
+The other operands are tracked by the ``MCCFIInstruction`` object.
+
+The syntax is:
+
+.. code-block:: text
+
+    CFI_INSTRUCTION offset %w30, -16
+
+which may be emitted later in the MC layer as:
+
+.. code-block:: text
+
+    .cfi_offset w30, -16
+
 .. TODO: Describe the parsers default behaviour when optional YAML attributes
    are missing.
 .. TODO: Describe the syntax for the bundled instructions.
@@ -702,7 +723,6 @@ The syntax is:
 .. TODO: Describe the syntax of the stack object machine operands and their
    YAML definitions.
 .. TODO: Describe the syntax of the block address machine operands.
-.. TODO: Describe the syntax of the CFI index machine operands.
 .. TODO: Describe the syntax of the metadata machine operands, and the
    instructions debug location attribute.
 .. TODO: Describe the syntax of the register live out machine operands.