[llvm][support] Add LDBG macro. #143704
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[llvm][support] Add LDBG macro. #143704
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@llvm/pr-subscribers-llvm-support Author: Jacques Pienaar (jpienaar) ChangesAdd macro that mirror a common usage of logging to output (e.g., one I invariably end up creating locally often). 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. Full diff: https://github.com/llvm/llvm-project/pull/143704.diff 2 Files Affected:
diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
new file mode 100644
index 0000000000000..d83c951bd23e2
--- /dev/null
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -0,0 +1,69 @@
+//===- 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.,
+// LLVM_DLOG() << "Bitset contains: " << Bitset;
+// is equivalent to
+// LLVM_DEBUG(dbgs() << DEBUG_TYPE << " " << __FILE__ << ":" << __LINE__
+// << "] " << "Bitset contains: " << Bitset << "\n");
+#define LLVM_DLOG(...) \
+ DEBUGLOG_WITH_STREAM_AND_TYPE(llvm::dbgs(), DEBUG_TYPE, __VA_ARGS__)
+
+#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 LLVM_DLOG() are ignored.
+#define LLVM_DLOG(...) \
+ for (bool _c = false; _c; _c = false) \
+ ::llvm::nulls()
+#endif
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_DEBUGLOG_H
diff --git a/llvm/unittests/Support/DebugLogTest.cpp b/llvm/unittests/Support/DebugLogTest.cpp
new file mode 100644
index 0000000000000..84208f5dc7e40
--- /dev/null
+++ b/llvm/unittests/Support/DebugLogTest.cpp
@@ -0,0 +1,39 @@
+//===- 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::HasSubstr;
+
+#ifndef NDEBUG
+TEST(DebugLogTest, Basic) {
+ std::string s1, s2;
+ raw_string_ostream os1(s1), os2(s2);
+ static const char *DT[] = {"A", "B"};
+
+ llvm::DebugFlag = true;
+ setCurrentDebugTypes(DT, 2);
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os1, "A") << "A";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os1, "B") << "B";
+ EXPECT_THAT(os1.str(), AllOf(HasSubstr("A\n"), HasSubstr("B\n")));
+
+ setCurrentDebugType("A");
+ volatile int x = 0;
+ if (x == 0)
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os2, "A") << "A";
+ else
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os2, "A") << "B";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os2, "B") << "B";
+ EXPECT_THAT(os2.str(), AllOf(HasSubstr("A\n"), Not(HasSubstr("B\n"))));
+}
+#endif
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✅ With the latest revision this PR passed the C/C++ code formatter. |
Add macro that mirror a common usage of logging to output (e.g., one I invariably end up creating locally often). 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.
joker-eph
reviewed
Jul 8, 2025
joker-eph
reviewed
Jul 8, 2025
joker-eph
reviewed
Jul 8, 2025
|
This looks really nice! |
joker-eph
reviewed
Jul 17, 2025
joker-eph
reviewed
Jul 17, 2025
joker-eph
approved these changes
Jul 17, 2025
joker-eph
reviewed
Jul 17, 2025
| #ifndef LLVM_SUPPORT_DEBUGLOG_H | ||
| #define LLVM_SUPPORT_DEBUGLOG_H | ||
|
|
||
| #include "llvm/Support/Debug.h" |
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Have you considered making this part of the Debug.h header directly?
Co-authored-by: Mehdi Amini <[email protected]>
… upstream uses. And test without debug type given.
jpienaar
changed the title
joker-eph
reviewed
Jul 24, 2025
joker-eph
approved these changes
Jul 24, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/2/builds/29743 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/123/builds/24051 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/63/builds/8163 Here is the relevant piece of the build log for the reference |
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/202/builds/2474 Here is the relevant piece of the build log for the reference |
|
Working on fix |
kuhar
reviewed
Jul 25, 2025
| // 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) |
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Should we prefix this with LLVM_? In the past, we used DEBUG instead of LLVM_DEBUG which caused naming collisions downstream: https://discourse.llvm.org/t/rfc-change-debug-macro-to-llvm-debug/48092 . I wonder if LDBG may be terse enough to run into similar issues.
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@jpienaar this is great! Consider sending a PSA to discourse to advertise this. |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/127/builds/4191 Here is the relevant piece of the build log for the reference |
mahesh-attarde
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Jul 28, 2025
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 <[email protected]>
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/49/builds/1938 Here is the relevant piece of the build log for the reference |
Yu-Zhewen
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Oct 29, 2025
This change removes IREE’s local LDBG macro definition in favor of the LLVM-provided version introduced in llvm/llvm-project#143704. This update is also in preparation for llvm/llvm-project#165429, which would otherwise cause a macro redefinition error due to the existing local LDBG definition. Signed-off-by: Yu-Zhewen <[email protected]>
bangtianliu
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that referenced
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Oct 30, 2025
…22456) This change removes IREE’s local LDBG macro definition in favor of the LLVM-provided version introduced in llvm/llvm-project#143704. This update is also in preparation for llvm/llvm-project#165429, which would otherwise cause a macro redefinition error due to the existing local LDBG definition. Signed-off-by: Yu-Zhewen <[email protected]>
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Add macro that mirror a common usage of logging to output (e.g., one I invariably end up creating locally often). 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.