[llvm] [llvm-objdump] Add triple support to `mcpu=help` (PR #165661)

[Ruoyu Qiu via llvm-commits]

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@@ -14,3 +14,30 @@ FileHeader:
   Data:            ELFDATA2LSB
   Type:            ET_EXEC
   Machine:         EM_X86_64
+
+# RUN: cp %t a.out
+# RUN: llvm-objdump -d --mcpu=help 2>&1 \
+# RUN:   | FileCheck %s --check-prefix=CHECK-DEFAULT-FILE
+# RUN: rm a.out
+
+# CHECK-DEFAULT-FILE: Available CPUs for this target:
+# CHECK-DEFAULT-FILE: Available features for this target:
+
+# RUN: llvm-objdump --triple=arm --mcpu=help %t 2>&1 \
+# RUN:   | FileCheck %s --check-prefix=CHECK-TRIPLE-PRIORITY
+
+# CHECK-TRIPLE-PRIORITY: Available CPUs for this target:
+# CHECK-TRIPLE-PRIORITY: Available features for this target:
+# CHECK-TRIPLE-PRIORITY: arm
+
+# RUN: not llvm-objdump --triple=x86_64 --mcpu=help 2>&1 \
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cabbaken wrote:

This case is for "--mcpu=help + no --disassemble + no objects specified + other dump options, --triple".
Since the other dump options require a file (which is missing here), an error is reported.

https://github.com/llvm/llvm-project/pull/165661