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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/CommandGuide/FileCheck.rst | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/docs/CommandGuide/FileCheck.rst b/docs/CommandGuide/FileCheck.rst index 049e10bbcf..ba2fe4ad9c 100644 --- a/docs/CommandGuide/FileCheck.rst +++ b/docs/CommandGuide/FileCheck.rst @@ -252,3 +252,30 @@ advantage of the fact that FileCheck is not actually line-oriented when it matches, this allows you to define two separate "``CHECK``" lines that match on the same line. + +FileCheck Expressions +~~~~~~~~~~~~~~~~~~~~~ + + +Sometimes there's a need to verify output which refers line numbers of the match +file, e.g. when testing compiler diagnostics. This introduces a certain +fragility of the match file structure, as CHECK: lines contain absolute line +numbers in the same file, which have to be updated whenever line numbers change +due to text addition or deletion. + +To support this case, FileCheck allows using ``[[@LINE]]``, +``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These +expressions expand to a number of the line where a pattern is located (with an +optional integer offset). + +This way match patterns can be put near the relevant test lines and include +relative line number references, for example: + +.. code-block:: c++ + + // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator + // CHECK-NEXT: {{^int a}} + // CHECK-NEXT: {{^ \^}} + // CHECK-NEXT: {{^ ;}} + int a + |