[llvm] Add support for the .base64 directive (fixes #165499) (PR #165549)

[Fangrui Song via llvm-commits]

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@@ -0,0 +1,28 @@
+# RUN: not llvm-mc -triple i386-unknown-unknown %s | FileCheck %s
+# RUN: not llvm-mc -triple i386-unknown-unknown -o /dev/null %s 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
+
+        .data
+# CHECK: TEST0:
+# CHECK: .byte 0
+TEST0:
+        .base64 "AA=="
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MaskRay wrote:

Should have consecutive `.base64` lines to ensure that the newline is correctly consumed.

Use `CHECK-NEXT:` whenever applicable

https://github.com/llvm/llvm-project/pull/165549