[llvm-branch-commits] [llvm] [lit] Add lit.llvm.fn_param shared helper for --param fn= substitutions (PR #200350)
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Sat May 30 18:30:31 PDT 2026
https://github.com/jofrn updated https://github.com/llvm/llvm-project/pull/200350
>From 0064cee8f2d0e5bceb05b51dd24d664e47d92c1b Mon Sep 17 00:00:00 2001
From: jofrn <165626406+jofrn at users.noreply.github.com>
Date: Sat, 30 May 2026 16:52:22 -0700
Subject: [PATCH 1/2] [FileCheck] Add --filter-label to drop CHECKs outside
selected CHECK-LABEL sections
---
llvm/include/llvm/FileCheck/FileCheck.h | 5 +++
llvm/lib/FileCheck/FileCheck.cpp | 24 ++++++++++++
llvm/lib/FileCheck/FileCheckImpl.h | 5 +++
llvm/test/FileCheck/filter-label.txt | 51 +++++++++++++++++++++++++
llvm/utils/FileCheck/FileCheck.cpp | 14 +++++++
5 files changed, 99 insertions(+)
create mode 100644 llvm/test/FileCheck/filter-label.txt
diff --git a/llvm/include/llvm/FileCheck/FileCheck.h b/llvm/include/llvm/FileCheck/FileCheck.h
index b000f5b0dac73..fbca647672e9e 100644
--- a/llvm/include/llvm/FileCheck/FileCheck.h
+++ b/llvm/include/llvm/FileCheck/FileCheck.h
@@ -13,6 +13,7 @@
#ifndef LLVM_FILECHECK_FILECHECK_H
#define LLVM_FILECHECK_FILECHECK_H
+#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
@@ -502,6 +503,10 @@ class FileCheck {
LLVM_ABI StringRef CanonicalizeFile(MemoryBuffer &MB,
SmallVectorImpl<char> &OutputBuffer);
+ /// Drops CHECKs whose CHECK-LABEL section's literal text doesn't match any
+ /// of \p Names. CHECKs before the first label are dropped. Nop if empty.
+ LLVM_ABI void filterByLabel(ArrayRef<StringRef> Names);
+
/// Checks the input to FileCheck provided in the \p Buffer against the
/// expected strings read from the check file and record diagnostics emitted
/// in \p Diags. Errors are recorded against \p SM.
diff --git a/llvm/lib/FileCheck/FileCheck.cpp b/llvm/lib/FileCheck/FileCheck.cpp
index ae25a078713e7..6a4f9c5a8343b 100644
--- a/llvm/lib/FileCheck/FileCheck.cpp
+++ b/llvm/lib/FileCheck/FileCheck.cpp
@@ -2531,6 +2531,30 @@ static bool ValidatePrefixes(StringRef Kind, StringSet<> &UniquePrefixes,
return true;
}
+void FileCheck::filterByLabel(ArrayRef<StringRef> Names) {
+ if (Names.empty())
+ return;
+
+ // (name1|name2|...) bracketed by non-chars (or string ends).
+ std::string Alts;
+ for (StringRef Name : Names) {
+ if (!Alts.empty())
+ Alts += '|';
+ Alts += Regex::escape(Name);
+ }
+ Regex Re("(^|[^[:alnum:]_])(" + Alts + ")([^[:alnum:]_]|$)");
+
+ std::vector<FileCheckString> Filtered;
+ bool Keeping = false;
+ for (auto &CS : CheckStrings) {
+ if (CS.Pat.getCheckTy() == Check::CheckLabel)
+ Keeping = Re.match(CS.Pat.getFixedStr());
+ if (Keeping)
+ Filtered.push_back(std::move(CS));
+ }
+ CheckStrings = std::move(Filtered);
+}
+
bool FileCheck::ValidateCheckPrefixes() {
StringSet<> UniquePrefixes;
// Add default prefixes to catch user-supplied duplicates of them below.
diff --git a/llvm/lib/FileCheck/FileCheckImpl.h b/llvm/lib/FileCheck/FileCheckImpl.h
index 5393650020a30..b156daaf40ab1 100644
--- a/llvm/lib/FileCheck/FileCheckImpl.h
+++ b/llvm/lib/FileCheck/FileCheckImpl.h
@@ -745,6 +745,11 @@ class Pattern {
Check::FileCheckType getCheckTy() const { return CheckTy; }
+ /// \returns the literal pattern text, or an empty StringRef if the pattern
+ /// requires a regex match. Used by FileCheck::filterByLabel to identify
+ /// CHECK-LABEL sections by their literal text.
+ StringRef getFixedStr() const { return FixedStr; }
+
int getCount() const { return CheckTy.getCount(); }
private:
diff --git a/llvm/test/FileCheck/filter-label.txt b/llvm/test/FileCheck/filter-label.txt
new file mode 100644
index 0000000000000..db5d5e3df3671
--- /dev/null
+++ b/llvm/test/FileCheck/filter-label.txt
@@ -0,0 +1,51 @@
+; Verify --filter-label drops CHECKs whose CHECK-LABEL section's literal text
+; doesn't match any of the given names.
+
+; RUN: FileCheck --filter-label=foo -input-file %s %s -check-prefix=ALL
+; RUN: FileCheck --filter-label=bar -input-file %s %s -check-prefix=ALL
+; RUN: FileCheck --filter-label=foo,bar -input-file %s %s -check-prefix=ALL
+; RUN: FileCheck --filter-label=bar,foo -input-file %s %s -check-prefix=ALL
+
+; RUN: %ProtectFileCheckOutput \
+; RUN: not FileCheck --filter-label=foobar -input-file %s %s -check-prefix=ALL 2>&1 \
+; RUN: | FileCheck %s -check-prefix=FAIL-ERR
+
+; RUN: %ProtectFileCheckOutput \
+; RUN: not FileCheck -input-file %s %s -check-prefix=ALL 2>&1 \
+; RUN: | FileCheck %s -check-prefix=FAIL-ERR
+
+; RUN: %ProtectFileCheckOutput \
+; RUN: not FileCheck --filter-label=baz -input-file %s %s -check-prefix=BAZ 2>&1 \
+; RUN: | FileCheck %s -check-prefix=FAIL-ERR
+
+
+ at foo:
+a
+b
+
+ at bar:
+c
+d
+
+ at foobar:
+e
+f
+
+ at baz:
+g
+h
+
+; ALL-LABEL: @foo:
+; ALL: {{^}}a
+; ALL: {{^}}b
+; ALL-LABEL: @bar:
+; ALL: {{^}}c
+; ALL: {{^}}d
+; ALL-LABEL: @foobar:
+; ALL: {{^}}e
+; ALL: {{^}}MISMATCH
+; BAZ-LABEL: @baz:
+; BAZ: {{^}}g
+; BAZ: {{^}}i
+
+; FAIL-ERR: expected string not found in input
diff --git a/llvm/utils/FileCheck/FileCheck.cpp b/llvm/utils/FileCheck/FileCheck.cpp
index 63b745469b8ee..82c71b0975534 100644
--- a/llvm/utils/FileCheck/FileCheck.cpp
+++ b/llvm/utils/FileCheck/FileCheck.cpp
@@ -143,6 +143,14 @@ enum DumpInputFilterValue {
DumpInputFilterAll
};
+static cl::list<std::string> FilterLabel(
+ "filter-label", cl::CommaSeparated,
+ cl::desc("Drop CHECKs whose enclosing CHECK-LABEL section's literal text\n"
+ "doesn't word-match any of the given labels. CHECKs before the\n"
+ "first label are dropped. Useful for narrowing checks to a subset\n"
+ "of functions."),
+ cl::value_desc("name"));
+
static cl::list<DumpInputFilterValue> DumpInputFilters(
"dump-input-filter",
cl::desc("In the dump requested by -dump-input, print only input lines of\n"
@@ -868,6 +876,12 @@ int main(int argc, char **argv) {
if (FC.readCheckFile(SM, CheckFileText, &ImpPatBufferIDRange))
return 2;
+ if (!FilterLabel.empty()) {
+ SmallVector<StringRef, 4> FilterLabelRefs(FilterLabel.begin(),
+ FilterLabel.end());
+ FC.filterByLabel(FilterLabelRefs);
+ }
+
// Open the file to check and add it to SourceMgr.
ErrorOr<std::unique_ptr<MemoryBuffer>> InputFileOrErr =
MemoryBuffer::getFileOrSTDIN(InputFilename, /*IsText=*/true);
>From 80ed9c8e6fa5c21676fa381b955c6b11fa0ea77e Mon Sep 17 00:00:00 2001
From: jofrn <165626406+jofrn at users.noreply.github.com>
Date: Fri, 29 May 2026 01:09:16 -0700
Subject: [PATCH 2/2] [lit] Add lit.llvm.fn_param shared helper for --param fn=
substitutions
---
llvm/test/lit.cfg.py | 6 ++++
llvm/utils/lit/lit/llvm/fn_param.py | 46 +++++++++++++++++++++++++++++
2 files changed, 52 insertions(+)
create mode 100644 llvm/utils/lit/lit/llvm/fn_param.py
diff --git a/llvm/test/lit.cfg.py b/llvm/test/lit.cfg.py
index 09df1e3fd6281..f4b9e8aaed6ef 100644
--- a/llvm/test/lit.cfg.py
+++ b/llvm/test/lit.cfg.py
@@ -39,6 +39,12 @@
)
config.test_format = lit.formats.ShTest(not use_lit_shell, extra_substitutions)
+# --param fn=NAMES narrows compilation to the named functions and their
+# transitive dependencies. See lit.llvm.fn_param.install for dispatch details.
+from lit.llvm import fn_param
+
+fn_param.install(config, lit_config)
+
# suffixes: A list of file extensions to treat as test files. This is overriden
# by individual lit.local.cfg files in the test subdirectories.
config.suffixes = [".ll", ".c", ".test", ".txt", ".s", ".mir", ".yaml", ".spv"]
diff --git a/llvm/utils/lit/lit/llvm/fn_param.py b/llvm/utils/lit/lit/llvm/fn_param.py
new file mode 100644
index 0000000000000..48d8400b80155
--- /dev/null
+++ b/llvm/utils/lit/lit/llvm/fn_param.py
@@ -0,0 +1,46 @@
+"""Shared building blocks for `--param fn=NAMES`-driven lit substitutions.
+
+Used by `lit.llvm.fn_selection` and `lit.llvm.fn_extract` to narrow compilation
+to a subset of functions. Kept here so the two helpers stay short and share
+parsing + capture-substitution wiring."""
+
+from lit.TestingConfig import SubstituteCaptures
+
+
+def parse_fn_names(lit_config, param="fn"):
+ """Return the comma-separated list passed via `--param <param>=NAMES`,
+ or an empty list when the param is absent or empty."""
+ val = lit_config.params.get(param)
+ if not val:
+ return []
+ return [n.strip() for n in val.split(",") if n.strip()]
+
+
+def add_capture_sub(config, pattern, replacement):
+ """Append a substitution that preserves regex backreferences in `replacement`."""
+ config.substitutions.append((pattern, SubstituteCaptures(replacement)))
+
+
+def install(config, lit_config):
+ """Dispatch `--param fn=NAMES` to the right helper, and ask FileCheck to
+ drop CHECKs outside the selected CHECK-LABEL sections.
+
+ `--param fn-pass=1` opts into `lit.llvm.fn_selection` (the select-function
+ pass, opt-only); otherwise `lit.llvm.fn_extract` is used (prepends
+ llvm-extract, tool-agnostic)."""
+ names = parse_fn_names(lit_config)
+ if not names:
+ return
+ # Splice `--filter-label=NAMES` after any FileCheck invocation so the
+ # downstream FileCheck only checks the CHECK-LABEL sections we kept.
+ add_capture_sub(
+ config, r"(\S*FileCheck)\b", r"\1 --filter-label=" + ",".join(names)
+ )
+ if lit_config.params.get("fn-pass"):
+ # from lit.llvm import fn_selection
+ # fn_selection.install(config, lit_config)
+ pass
+ else:
+ # from lit.llvm import fn_extract
+ # fn_extract.install(config, lit_config)
+ pass
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