[lit] Fix some issues from --per-test-coverage (#65242)

D154280 (landed in 64d1954 in July, 2023) implements
`--per-test-coverage` (which can also be specified via 
`lit_config.per_test_coverage`).  However, it has a few issues, which
the current patch addresses:

1. D154280 implements `--per-test-coverage` only for the case that lit 
   is configured to use an external shell.  The current patch extends
   the implementation to lit's internal shell.

2. In the case that lit is configured to use an external shell,
   regardless of whether `--per-test-coverage` is actually specified,
   D154280 causes `%dbg(RUN: at line N)` to be expanded in RUN lines
   early and in a manner that is specific to sh-like shells.  As a
   result, later code in lit that expands it in a shell-specific
   manner is useless as there's nothing left to expand.  The current
   patch cleans up the implementation to avoid useless code.

3. Because of issue 2, D154280 corrupts support for windows `cmd` as
   an external shell (effectively comments out all RUN lines with
   `:`).  The current patch happens to fix that particular corruption
   by addressing issue 2.  However, D122569 (landed in 1041a96 in
   April, 2022) had already broken support for windows `cmd` as an
   external shell (discards RUN lines when expanding `%dbg(RUN: at
   line N)`).  The current patch does not attempt to fix that bug.
   For further details, see the PR discussion of the current patch.

The current patch addresses the above issues by implementing
`--per-test-coverage` before selecting the shell (internal or
external) and by leaving `%dbg(RUN: at line N)` unexpanded there.
Thus, it is expanded later in a shell-specific manner, as before
D154280.

This patch introduces `buildPdbgCommand` into lit's implementation to
encapsulate the process of building (or rebuilding in the case of the 
`--per-test-coverage` implementation) a full `%dbg(RUN: at line N)
cmd` line and asserting that the result matches `kPdbgRegex`.  It also
cleans up that and all other uses of `kPdbgRegex` to operate on the 
full line with `re.fullmatch` not `re.match`.  This change better
reflects the intention in every case, but it is expected to be NFC 
because `kPdbgRegex` ends in `.*` and thus avoids the difference
between `re.fullmatch` and `re.match`.  The only caveat is that `.*`
does not match newlines, but RUN lines cannot contain newlines
currently, so this caveat currently shouldn't matter in practice.

The original `--per-test-coverage` implementation avoided accumulating
`export LLVM_PROFILE_FILE={profile}` insertions across retries (due to
`ALLOW_RETRIES`) by skipping the insertion if `%dbg(RUN: at line N)` 
was not present and thus had already been expanded.  However, the 
current patch makes sure the insertions also happen for commands
without `%dbg(RUN: at line N)`, such as preamble commands or some
commands from other lit test formats.  Thus, the current patch
implements a different mechanism to avoid accumulating those
insertions (see code comments).

Author: jdenny-ornl

llvm/utils/lit/lit/TestRunner.py

@@ -57,6 +57,14 @@ def __init__(self, command, message):
 kPdbgRegex = "%dbg\\(([^)'\"]*)\\)(.*)"
 
 
+def buildPdbgCommand(msg, cmd):
+    res = f"%dbg({msg}) {cmd}"
+    assert re.fullmatch(
+        kPdbgRegex, res
+    ), f"kPdbgRegex expected to match actual %dbg usage: {res}"
+    return res
+
+
 class ShellEnvironment(object):
 
     """Mutable shell environment containing things like CWD and env vars.
@@ -985,7 +993,7 @@ def _executeShCmd(cmd, shenv, results, timeoutHelper):
 def executeScriptInternal(test, litConfig, tmpBase, commands, cwd):
     cmds = []
     for i, ln in enumerate(commands):
-        match = re.match(kPdbgRegex, ln)
+        match = re.fullmatch(kPdbgRegex, ln)
         if match:
             command = match.group(2)
             ln = commands[i] = match.expand(": '\\1'; \\2" if command else ": '\\1'")
@@ -1067,25 +1075,10 @@ def executeScriptInternal(test, litConfig, tmpBase, commands, cwd):
 def executeScript(test, litConfig, tmpBase, commands, cwd):
     bashPath = litConfig.getBashPath()
     isWin32CMDEXE = litConfig.isWindows and not bashPath
-    coverage_index = 0  # Counter for coverage file index
     script = tmpBase + ".script"
     if isWin32CMDEXE:
         script += ".bat"
 
-    # Set unique LLVM_PROFILE_FILE for each run command
-    for j, ln in enumerate(commands):
-        match = re.match(kPdbgRegex, ln)
-        if match:
-            command = match.group(2)
-            commands[j] = match.expand(": '\\1'; \\2" if command else ": '\\1'")
-            if litConfig.per_test_coverage:
-                # Extract the test case name from the test object
-                test_case_name = test.path_in_suite[-1]
-                test_case_name = test_case_name.rsplit(".", 1)[0]  # Remove the file extension
-                llvm_profile_file = f"{test_case_name}{coverage_index}.profraw"
-                commands[j] = f"export LLVM_PROFILE_FILE={llvm_profile_file} && {commands[j]}"
-                coverage_index += 1
-
     # Write script file
     mode = "w"
     open_kwargs = {}
@@ -1096,7 +1089,7 @@ def executeScript(test, litConfig, tmpBase, commands, cwd):
     f = open(script, mode, **open_kwargs)
     if isWin32CMDEXE:
         for i, ln in enumerate(commands):
-            match = re.match(kPdbgRegex, ln)
+            match = re.fullmatch(kPdbgRegex, ln)
             if match:
                 command = match.group(2)
                 commands[i] = match.expand(
@@ -1109,7 +1102,7 @@ def executeScript(test, litConfig, tmpBase, commands, cwd):
         f.write("\n@if %ERRORLEVEL% NEQ 0 EXIT\n".join(commands))
     else:
         for i, ln in enumerate(commands):
-            match = re.match(kPdbgRegex, ln)
+            match = re.fullmatch(kPdbgRegex, ln)
             if match:
                 command = match.group(2)
                 commands[i] = match.expand(": '\\1'; \\2" if command else ": '\\1'")
@@ -1837,13 +1830,7 @@ def _handleCommand(cls, line_number, line, output, keyword):
         if not output or not output[-1].add_continuation(line_number, keyword, line):
             if output is None:
                 output = []
-            pdbg = "%dbg({keyword} at line {line_number})".format(
-                keyword=keyword, line_number=line_number
-            )
-            assert re.match(
-                kPdbgRegex + "$", pdbg
-            ), "kPdbgRegex expected to match actual %dbg usage"
-            line = "{pdbg} {real_command}".format(pdbg=pdbg, real_command=line)
+            line = buildPdbgCommand(f"{keyword} at line {line_number}", line)
             output.append(CommandDirective(line_number, line_number, keyword, line))
         return output
 
@@ -2048,6 +2035,27 @@ def parseIntegratedTestScript(test, additional_parsers=[], require_script=True):
 
 def _runShTest(test, litConfig, useExternalSh, script, tmpBase):
     def runOnce(execdir):
+        # Set unique LLVM_PROFILE_FILE for each run command
+        if litConfig.per_test_coverage:
+            # Extract the test case name from the test object, and remove the
+            # file extension.
+            test_case_name = test.path_in_suite[-1]
+            test_case_name = test_case_name.rsplit(".", 1)[0]
+            coverage_index = 0  # Counter for coverage file index
+            for i, ln in enumerate(script):
+                match = re.fullmatch(kPdbgRegex, ln)
+                if match:
+                    dbg = match.group(1)
+                    command = match.group(2)
+                else:
+                    command = ln
+                profile = f"{test_case_name}{coverage_index}.profraw"
+                coverage_index += 1
+                command = f"export LLVM_PROFILE_FILE={profile}; {command}"
+                if match:
+                    command = buildPdbgCommand(dbg, command)
+                script[i] = command
+
         if useExternalSh:
             res = executeScript(test, litConfig, tmpBase, script, execdir)
         else:
@@ -2071,7 +2079,14 @@ def runOnce(execdir):
     # Re-run failed tests up to test.allowed_retries times.
     execdir = os.path.dirname(test.getExecPath())
     attempts = test.allowed_retries + 1
+    scriptInit = script
     for i in range(attempts):
+        # runOnce modifies script, but applying the modifications again to the
+        # result can corrupt script, so we restore the original upon a retry.
+        # A cleaner solution would be for runOnce to encapsulate operating on a
+        # copy of script, but we actually want it to modify the original script
+        # so we can print the modified version under "Script:" below.
+        script = scriptInit[:]
         res = runOnce(execdir)
         if isinstance(res, lit.Test.Result):
             return res

llvm/utils/lit/tests/Inputs/per-test-coverage-by-lit-cfg/lit.cfg

@@ -3,6 +3,9 @@ import os
 
 config.name = "per-test-coverage-by-lit-cfg"
 config.suffixes = [".py"]
-config.test_format = lit.formats.ShTest(execute_external=True)
+config.test_format = lit.formats.ShTest(
+    execute_external=eval(lit_config.params.get("execute_external")),
+    preamble_commands=["%{python} %s | FileCheck -DINDEX=0 %s"]
+)
 lit_config.per_test_coverage = True
 config.substitutions.append(("%{python}", '"%s"' % (sys.executable)))

llvm/utils/lit/tests/Inputs/per-test-coverage-by-lit-cfg/per-test-coverage-by-lit-cfg.py

@@ -1,5 +1,6 @@
 # Check that the environment variable is set correctly
-# RUN: %{python} %s | FileCheck %s
+# RUN: %{python} %s | FileCheck -DINDEX=1 %s
+# RUN: %{python} %s | FileCheck -DINDEX=2 %s
 
 # Python script to read the environment variable
 # and print its value
@@ -8,4 +9,4 @@
 llvm_profile_file = os.environ.get('LLVM_PROFILE_FILE')
 print(llvm_profile_file)
 
-# CHECK: per-test-coverage-by-lit-cfg0.profraw
+# CHECK: per-test-coverage-by-lit-cfg[[INDEX]].profraw

llvm/utils/lit/tests/Inputs/per-test-coverage/lit.cfg

@@ -3,6 +3,8 @@ import os
 
 config.name = "per-test-coverage"
 config.suffixes = [".py"]
-config.test_format = lit.formats.ShTest(execute_external=True)
+config.test_format = lit.formats.ShTest(
+    execute_external=eval(lit_config.params.get("execute_external")),
+    preamble_commands=["%{python} %s | FileCheck -DINDEX=0 %s"]
+)
 config.substitutions.append(("%{python}", '"%s"' % (sys.executable)))
-

llvm/utils/lit/tests/Inputs/per-test-coverage/per-test-coverage.py

@@ -1,5 +1,6 @@
 # Check that the environment variable is set correctly
-# RUN: %{python} %s | FileCheck %s
+# RUN: %{python} %s | FileCheck -DINDEX=1 %s
+# RUN: %{python} %s | FileCheck -DINDEX=2 %s
 
 # Python script to read the environment variable
 # and print its value
@@ -8,4 +9,4 @@
 llvm_profile_file = os.environ.get('LLVM_PROFILE_FILE')
 print(llvm_profile_file)
 
-# CHECK: per-test-coverage0.profraw
+# CHECK: per-test-coverage[[INDEX]].profraw

llvm/utils/lit/tests/allow-retries.py

@@ -39,3 +39,15 @@
 # RUN: rm -f %t.counter
 # RUN: %{lit} %{inputs}/test_retry_attempts/test.py -Dcounter=%t.counter -Dpython=%{python} | FileCheck --check-prefix=CHECK-TEST6 %s
 # CHECK-TEST6: Passed With Retry: 1
+
+# This test checks that --per-test-coverage doesn't accumulate inserted
+# LLVM_PROFILE_FILE= commands across retries.
+#
+# RUN: rm -f %t.counter
+# RUN: %{lit} -a %{inputs}/test_retry_attempts/test.py --per-test-coverage\
+# RUN:     -Dcounter=%t.counter -Dpython=%{python} | \
+# RUN:   FileCheck --check-prefix=CHECK-TEST7 %s
+#     CHECK-TEST7: Command Output (stdout):
+#     CHECK-TEST7: LLVM_PROFILE_FILE=
+# CHECK-TEST7-NOT: LLVM_PROFILE_FILE=
+#     CHECK-TEST7: Passed With Retry: 1

llvm/utils/lit/tests/per-test-coverage-by-lit-cfg.py

@@ -1,6 +1,24 @@
 # Test if lit_config.per_test_coverage in lit.cfg sets individual test case coverage.
 
-# RUN: %{lit} -a -v %{inputs}/per-test-coverage-by-lit-cfg/per-test-coverage-by-lit-cfg.py \
-# RUN: | FileCheck -match-full-lines %s
-#
-# CHECK: PASS: per-test-coverage-by-lit-cfg :: per-test-coverage-by-lit-cfg.py ({{[^)]*}})
+# RUN: %{lit} -a -vv -Dexecute_external=False \
+# RUN:     %{inputs}/per-test-coverage-by-lit-cfg/per-test-coverage-by-lit-cfg.py | \
+# RUN:   FileCheck -DOUT=stdout %s
+
+# RUN: %{lit} -a -vv -Dexecute_external=True \
+# RUN:     %{inputs}/per-test-coverage-by-lit-cfg/per-test-coverage-by-lit-cfg.py | \
+# RUN:   FileCheck -DOUT=stderr %s
+
+#      CHECK: {{^}}PASS: per-test-coverage-by-lit-cfg :: per-test-coverage-by-lit-cfg.py ({{[^)]*}})
+#      CHECK: Command Output ([[OUT]]):
+# CHECK-NEXT: --
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage-by-lit-cfg0.profraw
+#      CHECK: per-test-coverage-by-lit-cfg.py
+#      CHECK: {{RUN}}: at line 2
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage-by-lit-cfg1.profraw
+#      CHECK: per-test-coverage-by-lit-cfg.py
+#      CHECK: {{RUN}}: at line 3
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage-by-lit-cfg2.profraw
+#      CHECK: per-test-coverage-by-lit-cfg.py

llvm/utils/lit/tests/per-test-coverage.py

@@ -1,6 +1,24 @@
 # Test LLVM_PROFILE_FILE is set when --per-test-coverage is passed to command line.
 
-# RUN: %{lit} -a -v --per-test-coverage %{inputs}/per-test-coverage/per-test-coverage.py \
-# RUN: | FileCheck -match-full-lines %s
-#
-# CHECK: PASS: per-test-coverage :: per-test-coverage.py ({{[^)]*}})
+# RUN: %{lit} -a -vv --per-test-coverage -Dexecute_external=False \
+# RUN:     %{inputs}/per-test-coverage/per-test-coverage.py | \
+# RUN:   FileCheck -DOUT=stdout %s
+
+# RUN: %{lit} -a -vv --per-test-coverage -Dexecute_external=True \
+# RUN:        %{inputs}/per-test-coverage/per-test-coverage.py | \
+# RUN:   FileCheck -DOUT=stderr %s
+
+#      CHECK: {{^}}PASS: per-test-coverage :: per-test-coverage.py ({{[^)]*}})
+#      CHECK: Command Output ([[OUT]]):
+# CHECK-NEXT: --
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage0.profraw
+#      CHECK: per-test-coverage.py
+#      CHECK: {{RUN}}: at line 2
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage1.profraw
+#      CHECK: per-test-coverage.py
+#      CHECK: {{RUN}}: at line 3
+#      CHECK: export
+#      CHECK: LLVM_PROFILE_FILE=per-test-coverage2.profraw
+#      CHECK: per-test-coverage.py