[llvm] d368d11 - [llvm][support] Add LDBG macro. (#143704)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 24 21:58:08 PDT 2025
Author: Jacques Pienaar
Date: 2025-07-25T06:58:05+02:00
New Revision: d368d117e7ee9720acd3eac6fb41c0885575a114
URL: https://github.com/llvm/llvm-project/commit/d368d117e7ee9720acd3eac6fb41c0885575a114
DIFF: https://github.com/llvm/llvm-project/commit/d368d117e7ee9720acd3eac6fb41c0885575a114.diff
LOG: [llvm][support] Add LDBG macro. (#143704)
Add macro that mirror a common usage of logging to output .This makes it easy to have
streaming log like behavior while still using the base debug logging.
I also wanted to avoid inventing a full logging library here while enabling others to change the sink without too much pain, so put it in its own header (this also avoids making Debug depend on raw_ostream beyond forward reference). The should allow a consistent dev experience without fixing the sink too much.
---------
Co-authored-by: Mehdi Amini <joker.eph at gmail.com>
Added:
llvm/include/llvm/Support/DebugLog.h
llvm/unittests/Support/DebugLogTest.cpp
Modified:
llvm/unittests/Support/CMakeLists.txt
Removed:
################################################################################
diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
new file mode 100644
index 0000000000000..9556bf2d6242d
--- /dev/null
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -0,0 +1,68 @@
+//===- llvm/Support/DebugLog.h - Logging like debug output ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// This file contains macros for logging like debug output. It builds upon the
+// support in Debug.h but provides a utility function for common debug output
+// style.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_DEBUGLOG_H
+#define LLVM_SUPPORT_DEBUGLOG_H
+
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+
+namespace llvm {
+#ifndef NDEBUG
+
+// Output with given inputs and trailing newline. E.g.,
+// LDBG() << "Bitset contains: " << Bitset;
+// is equivalent to
+// LLVM_DEBUG(dbgs() << DEBUG_TYPE << " [" << __FILE__ << ":" << __LINE__
+// << "] " << "Bitset contains: " << Bitset << "\n");
+#define LDBG() DEBUGLOG_WITH_STREAM_AND_TYPE(llvm::dbgs(), DEBUG_TYPE)
+
+#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE) \
+ for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c; \
+ _c = false) \
+ ::llvm::impl::LogWithNewline(TYPE, __FILE__, __LINE__, (STREAM))
+
+namespace impl {
+class LogWithNewline {
+public:
+ LogWithNewline(const char *debug_type, const char *file, int line,
+ raw_ostream &os)
+ : os(os) {
+ if (debug_type)
+ os << debug_type << " ";
+ os << "[" << file << ":" << line << "] ";
+ }
+ ~LogWithNewline() { os << '\n'; }
+ template <typename T> raw_ostream &operator<<(const T &t) && {
+ return os << t;
+ }
+
+ // Prevent copying, as this class manages newline responsibility and is
+ // intended for use as a temporary.
+ LogWithNewline(const LogWithNewline &) = delete;
+ LogWithNewline &operator=(const LogWithNewline &) = delete;
+ LogWithNewline &operator=(LogWithNewline &&) = delete;
+
+private:
+ raw_ostream &os;
+};
+} // end namespace impl
+#else
+// As others in Debug, When compiling without assertions, the -debug-* options
+// and all inputs too LDBG() are ignored.
+#define LDBG() \
+ for (bool _c = false; _c; _c = false) \
+ ::llvm::nulls()
+#endif
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_DEBUGLOG_H
diff --git a/llvm/unittests/Support/CMakeLists.txt b/llvm/unittests/Support/CMakeLists.txt
index d048e871fd0fb..868c40b13b9b2 100644
--- a/llvm/unittests/Support/CMakeLists.txt
+++ b/llvm/unittests/Support/CMakeLists.txt
@@ -31,6 +31,7 @@ add_llvm_unittest(SupportTests
DataExtractorTest.cpp
DebugCounterTest.cpp
DebugTest.cpp
+ DebugLogTest.cpp
DivisionByConstantTest.cpp
DJBTest.cpp
EndianStreamTest.cpp
diff --git a/llvm/unittests/Support/DebugLogTest.cpp b/llvm/unittests/Support/DebugLogTest.cpp
new file mode 100644
index 0000000000000..513699913f922
--- /dev/null
+++ b/llvm/unittests/Support/DebugLogTest.cpp
@@ -0,0 +1,77 @@
+//===- llvm/unittest/Support/DebugLogTest.cpp -----------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/DebugLog.h"
+#include "llvm/Support/raw_ostream.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#include <string>
+using namespace llvm;
+using testing::Eq;
+using testing::HasSubstr;
+
+#ifndef NDEBUG
+TEST(DebugLogTest, Basic) {
+ llvm::DebugFlag = true;
+ static const char *DT[] = {"A", "B"};
+
+ // Clear debug types.
+ setCurrentDebugTypes(DT, 0);
+ {
+ std::string str;
+ raw_string_ostream os(str);
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, nullptr) << "NoType";
+ EXPECT_TRUE(StringRef(os.str()).starts_with('['));
+ EXPECT_TRUE(StringRef(os.str()).ends_with("NoType\n"));
+ }
+
+ setCurrentDebugTypes(DT, 2);
+ {
+ std::string str;
+ raw_string_ostream os(str);
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << "A";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << "B";
+ EXPECT_THAT(os.str(), AllOf(HasSubstr("A\n"), HasSubstr("B\n")));
+ }
+
+ setCurrentDebugType("A");
+ {
+ std::string str;
+ raw_string_ostream os(str);
+ // Just check that the macro doesn't result in dangling else.
+ if (true)
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << "A";
+ else
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << "B";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << "B";
+ EXPECT_THAT(os.str(), AllOf(HasSubstr("A\n"), Not(HasSubstr("B\n"))));
+
+ int count = 0;
+ auto inc = [&]() { return ++count; };
+ EXPECT_THAT(count, Eq(0));
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << inc();
+ EXPECT_THAT(count, Eq(1));
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << inc();
+ EXPECT_THAT(count, Eq(1));
+ }
+}
+#else
+TEST(DebugLogTest, Basic) {
+ // LDBG should be compiled out in NDEBUG, so just check it compiles and has
+ // no effect.
+ llvm::DebugFlag = true;
+ static const char *DT[] = {};
+ setCurrentDebugTypes(DT, 0);
+ int count = 0;
+ auto inc = [&]() { return ++count; };
+ EXPECT_THAT(count, Eq(0));
+ LDBG() << inc();
+ EXPECT_THAT(count, Eq(0));
+}
+#endif
More information about the llvm-commits
mailing list