[llvm] [MC][WebAssembly] Convert tag section tests to assembly. NFC (PR #159141)

[Derek Schuff via llvm-commits]

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@@ -0,0 +1,63 @@
+# RUN: llvm-mc -triple=wasm32-unknown-unknown -mattr=+exception-handling -filetype=obj %s | obj2yaml | FileCheck %s
+# RUN: llvm-mc -triple=wasm32-unknown-unknown -mattr=+exception-handling -filetype=obj %s | llvm-readobj -S - | FileCheck -check-prefix=SEC %s
+
+.tagtype my_exception i32
+
+.globl test_throw0
+test_throw0:
+  .functype test_throw0 (i32) -> (i32)
+  i32.const 0
+  throw my_exception
+  i32.const 0
+  end_function
+
+.globl test_throw1
+test_throw1:
+  .functype test_throw1 (i32) -> (i32)
+  i32.const 0
+  throw my_exception
+  i32.const 0
+  end_function
+
+.globl my_exception
+my_exception:
+
+# CHECK:      Sections:
+# CHECK-NEXT:   - Type:            TYPE
+# CHECK-NEXT:     Signatures:
+# CHECK-NEXT:       - Index:           0
+# CHECK-NEXT:         ParamTypes:
+# CHECK-NEXT:           - I32
+# CHECK-NEXT:         ReturnTypes:
+# CHECK-NEXT:           - I32
+# CHECK-NEXT:       - Index:           1
+# CHECK-NEXT:         ParamTypes:
+# CHECK-NEXT:           - I32
+# CHECK-NEXT:         ReturnTypes:      []
+
+# CHECK:        - Type:            TAG
+# CHECK-NEXT:     TagTypes:        [ 1 ]
+
+# CHECK-NEXT:   - Type:            CODE
+# CHECK-NEXT:     Relocations:
+# CHECK-NEXT:       - Type:            R_WASM_TAG_INDEX_LEB
+# CHECK-NEXT:         Index:           1
+# CHECK-NEXT:         Offset:          0x6
+# CHECK-NEXT:       - Type:            R_WASM_TAG_INDEX_LEB
+# CHECK-NEXT:         Index:           1
+# CHECK-NEXT:         Offset:          0x13
+
+# CHECK:        - Type:            CUSTOM
+# CHECK-NEXT:     Name:            linking
+# CHECK-NEXT:     Version:         2
+# CHECK-NEXT:     SymbolTable:
+
+# CHECK:            - Index:           1
+# CHECK-NEXT:         Kind:            TAG
+# CHECK-NEXT:         Name:            my_exception
+# CHECK-NEXT:         Flags:           [ ]
----------------
dschuff wrote:

I agree that defining a custom tag in the asm here makes sense, for the reason you say. Also generally speaking, an approach like that might be easier to get better coverage of the MC layer that the compiler might not use (although I'm not sure that's really happening here).

Really these are part of the benefit of having tests as asm rather than ll in the first place. 

Separately: IIRC we do still have tests that go from ll -> asm that cover the codegen here and they are unchanged, so I think that should be fine.

https://github.com/llvm/llvm-project/pull/159141