MIR Serialization: Change MIR syntax - use custom syntax for MBBs.

This commit modifies the way the machine basic blocks are serialized - now the
machine basic blocks are serialized using a custom syntax instead of relying on
YAML primitives. Instead of using YAML mappings to represent the individual
machine basic blocks in a machine function's body, the new syntax uses a single
YAML block scalar which contains all of the machine basic blocks and
instructions for that function.

This is an example of a function's body that uses the old syntax:

    body:
      - id: 0
        name: entry
        instructions:
          - '%eax = MOV32r0 implicit-def %eflags'
          - 'RETQ %eax'
    ...

The same body is now written like this:

    body: |
      bb.0.entry:
        %eax = MOV32r0 implicit-def %eflags
        RETQ %eax
    ...

This syntax change is motivated by the fact that the bundled machine
instructions didn't map that well to the old syntax which was using a single
YAML sequence to store all of the machine instructions in a block. The bundled
machine instructions internally use flags like BundledPred and BundledSucc to
determine the bundles, and serializing them as MI flags using the old syntax
would have had a negative impact on the readability and the ease of editing
for MIR files. The new syntax allows me to serialize the bundled machine
instructions using a block construct without relying on the internal flags,
for example:

   BUNDLE implicit-def dead %itstate, implicit-def %s1 ... {
      t2IT 1, 24, implicit-def %itstate
      %s1 = VMOVS killed %s0, 1, killed %cpsr, implicit killed %itstate
   }

This commit also converts the MIR testcases to the new syntax. I developed
a script that can convert from the old syntax to the new one. I will post the
script on the llvm-commits mailing list in the thread for this commit.

llvm-svn: 244982

1 files changed, 7 insertions, 9 deletions

diff --git a/llvm/test/CodeGen/MIR/X86/stack-object-operand-name-mismatch-error.mir b/llvm/test/CodeGen/MIR/X86/stack-object-operand-name-mismatch-error.mir
index a6ffb3b93e0..46661d95e72 100644
--- a/llvm/test/CodeGen/MIR/X86/stack-object-operand-name-mismatch-error.mir
+++ b/llvm/test/CodeGen/MIR/X86/stack-object-operand-name-mismatch-error.mir
@@ -23,13 +23,11 @@ frameInfo:
   maxAlignment:  4
 stack:
   - { id: 0, name: b, size: 4, alignment: 4 }
-body:
-  - id:          0
-    name:        entry
-    instructions:
-      - '%0 = COPY %edi'
-      # CHECK: [[@LINE+1]]:18: the name of the stack object '%stack.0' isn't 'x'
-      - 'MOV32mr %stack.0.x, 1, _, 0, _, %0'
-      - '%eax = COPY %0'
-      - 'RETQ %eax'
+body: |
+  bb.0.entry:
+    %0 = COPY %edi
+    ; CHECK: [[@LINE+1]]:13: the name of the stack object '%stack.0' isn't 'x'
+    MOV32mr %stack.0.x, 1, _, 0, _, %0
+    %eax = COPY %0
+    RETQ %eax
 ...