[FileCheck] Don't permit overlapping CHECK-DAG
That is, make CHECK-DAG skip matches that overlap the matches of any
preceding consecutive CHECK-DAG directives. This change makes
CHECK-DAG more consistent with other directives, and there is evidence
it makes CHECK-DAG more intuitive and less error-prone. See the RFC
discussion starting at:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123010.html
Moreover, this behavior enables CHECK-DAG groups for unordered,
non-unique strings or patterns. For example, it is useful for
verifying output or logs from a parallel program, such as the OpenMP
runtime.
This patch also implements the command-line option
-allow-deprecated-dag-overlap, which reverts CHECK-DAG to the old
overlapping behavior. This option should not be used in new tests.
It is meant only for the existing tests that are broken by this change
and that need time to update.
See the following bugzilla issue for tracking of such tests:
https://bugs.llvm.org/show_bug.cgi?id=37532
Patches to add -allow-deprecated-dag-overlap to those tests will
follow immediately.
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D47106
llvm-svn: 336847
diff --git a/llvm/docs/CommandGuide/FileCheck.rst b/llvm/docs/CommandGuide/FileCheck.rst
index ae662b5..ac7e810 100644
--- a/llvm/docs/CommandGuide/FileCheck.rst
+++ b/llvm/docs/CommandGuide/FileCheck.rst
@@ -95,6 +95,13 @@
Show the version number of this program.
+.. option:: --allow-deprecated-dag-overlap
+
+ Enable overlapping among matches in a group of consecutive ``CHECK-DAG:``
+ directives. This option is deprecated and is only provided for convenience
+ as old tests are migrated to the new non-overlapping ``CHECK-DAG:``
+ implementation.
+
EXIT STATUS
-----------
@@ -360,6 +367,25 @@
In those cases, to enforce the order, use a non-DAG directive between DAG-blocks.
+A ``CHECK-DAG:`` directive skips matches that overlap the matches of any
+preceding ``CHECK-DAG:`` directives in the same ``CHECK-DAG:`` block. Not only
+is this non-overlapping behavior consistent with other directives, but it's
+also necessary to handle sets of non-unique strings or patterns. For example,
+the following directives look for unordered log entries for two tasks in a
+parallel program, such as the OpenMP runtime:
+
+.. code-block:: text
+
+ // CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
+ // CHECK-DAG: [[THREAD_ID]]: task_end
+ //
+ // CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
+ // CHECK-DAG: [[THREAD_ID]]: task_end
+
+The second pair of directives is guaranteed not to match the same log entries
+as the first pair even though the patterns are identical and even if the text
+of the log entries is identical because the thread ID manages to be reused.
+
The "CHECK-LABEL:" directive
~~~~~~~~~~~~~~~~~~~~~~~~~~~~