[llvm] Introduce a "log level" support for DEBUG_TYPE (PR #150855)
Mehdi Amini via llvm-commits
llvm-commits at lists.llvm.org
Sun Jul 27 15:10:20 PDT 2025
https://github.com/joker-eph created https://github.com/llvm/llvm-project/pull/150855
This allows to set an optional integer level for a given debug type. The string format is `type[:level]`, and the integer is interpreted as such:
- if 0 (default): all debugging for this debug type is enabled.
- if -1: all debug for this debug type is disabled
- if >0: all debug that is < to the level is enabled.
This means that when checking which level is enabled, 0 and 1 are identical.
The LDBG() macro is updated to accept an optional log level to illustrate the feature. Here is the expected behavior:
LDBG() << "A";
LDBG(2) << "B";
With `--debug-only=some_type`: we'll see A and B in the output. With `--debug-only=some_type:-1`: we'll see neither A not B in the output. With `--debug-only=some_type:1`: we'll see A but not B in the output. With `--debug-only=some_type:2`: we'll see A and B in the output. (same with any level above 2)
Note that LDBG() is equivalent to LDBG(0) which is equivalent to LDBG(1).
>From 03401a5063d3f6481460996a0360d88c0a107d04 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <joker.eph at gmail.com>
Date: Sun, 27 Jul 2025 14:57:26 -0700
Subject: [PATCH] Introduce a "log level" support for DEBUG_TYPE
This allows to set an optional integer level for a given debug type.
The string format is `type[:level]`, and the integer is interpreted
as such:
- if 0 (default): all debugging for this debug type is enabled.
- if -1: all debug for this debug type is disabled
- if >0: all debug that is < to the level is enabled.
This means that when checking which level is enabled, 0 and 1 are identical.
The LDBG() macro is updated to accept an optional log level to illustrate
the feature. Here is the expected behavior:
LDBG() << "A";
LDBG(2) << "B";
With `--debug-only=some_type`: we'll see A and B in the output.
With `--debug-only=some_type:-1`: we'll see neither A not B in the output.
With `--debug-only=some_type:1`: we'll see A but not B in the output.
With `--debug-only=some_type:2`: we'll see A and B in the output.
(same with any level above 2)
Note that LDBG() is equivalent to LDBG(0) which is equivalent to LDBG(1).
---
llvm/include/llvm/Support/Debug.h | 11 ++++--
llvm/include/llvm/Support/DebugLog.h | 52 +++++++++++++++++++------
llvm/lib/Support/Debug.cpp | 50 +++++++++++++++++++-----
llvm/unittests/Support/DebugLogTest.cpp | 34 ++++++++++++----
4 files changed, 114 insertions(+), 33 deletions(-)
diff --git a/llvm/include/llvm/Support/Debug.h b/llvm/include/llvm/Support/Debug.h
index 924d7b216438e..2ce0bda3bdbbf 100644
--- a/llvm/include/llvm/Support/Debug.h
+++ b/llvm/include/llvm/Support/Debug.h
@@ -39,13 +39,18 @@ class raw_ostream;
/// isCurrentDebugType - Return true if the specified string is the debug type
/// specified on the command line, or if none was specified on the command line
/// with the -debug-only=X option.
-///
-bool isCurrentDebugType(const char *Type);
+/// An optional level can be provided to control the verbosity of the output.
+/// If the provided level is not 0 and user specified a level below the provided
+/// level, the output is disabled.
+bool isCurrentDebugType(const char *Type, int Level = 0);
/// setCurrentDebugType - Set the current debug type, as if the -debug-only=X
/// option were specified. Note that DebugFlag also needs to be set to true for
/// debug output to be produced.
-///
+/// The debug type format is "type[:level]", where the level is an optional
+/// integer. The default level is 0, which is the most verbose.
+/// The level can be set to 1, 2, 3, etc. to control the verbosity of the
+/// output. The level can be set to -1 to disable the output.
void setCurrentDebugType(const char *Type);
/// setCurrentDebugTypes - Set the current debug type, as if the
diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
index 19d309865bbd4..2541d60535ff7 100644
--- a/llvm/include/llvm/Support/DebugLog.h
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -19,29 +19,57 @@
namespace llvm {
#ifndef NDEBUG
-// Output with given inputs and trailing newline. E.g.,
+// LDBG() is a macro that can be used as a raw_ostream for debugging.
+// It will stream the output to the dbgs() stream, with a prefix of the
+// debug type and the file and line number. A trailing newline is added to the
+// output automatically. If the streamed content contains a newline, the prefix
+// is added to each beginning of a new line. Nothing is printed if the debug
+// output is not enabled or the debug type does not match.
+//
+// An optional `level` argument can be provided to control the verbosity of the
+// output. The default level is 0, which is the most verbose. The level can be
+// set to 1, 2, 3, etc. to control the verbosity of the output.
+//
+// The `level` argument can be a literal integer, or a macro that evaluates to
+// an integer.
+//
+// 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)
+// LLVM_DEBUG(dbgs() << "[" << DEBUG_TYPE << "] " << __FILE__ << ":" <<
+// __LINE__ << " "
+// << "Bitset contains: " << Bitset << "\n");
-#define DEBUGLOG_WITH_STREAM_TYPE_AND_FILE(STREAM, TYPE, FILE) \
- for (bool _c = (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE)); _c; \
- _c = false) \
+#define _GET_LDBG_MACRO(_1, NAME, ...) NAME
+#define LDBG(...) \
+ _GET_LDBG_MACRO(__VA_ARGS__, LDBG_LOG_LEVEL, LDBG_LOG_LEVEL_0)(__VA_ARGS__)
+
+#define LDBG_LOG_LEVEL(LEVEL) \
+ DEBUGLOG_WITH_STREAM_AND_TYPE(llvm::dbgs(), LEVEL, DEBUG_TYPE)
+#define LDBG_LOG_LEVEL_0() LDBG_LOG_LEVEL(0)
+
+#define DEBUGLOG_WITH_STREAM_TYPE_FILE_AND_LINE(STREAM, LEVEL, TYPE, FILE, \
+ LINE) \
+ for (bool _c = \
+ (::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE, LEVEL)); \
+ _c; _c = false) \
::llvm::impl::raw_ldbg_ostream{ \
- ::llvm::impl::computePrefix(TYPE, FILE, __LINE__), (STREAM)} \
+ ::llvm::impl::computePrefix(TYPE, FILE, LINE), (STREAM)} \
.asLvalue()
+
+#define DEBUGLOG_WITH_STREAM_TYPE_AND_FILE(STREAM, LEVEL, TYPE, FILE) \
+ DEBUGLOG_WITH_STREAM_TYPE_FILE_AND_LINE(STREAM, LEVEL, TYPE, FILE, __LINE__)
// When __SHORT_FILE__ is not defined, the File is the full path,
// otherwise __SHORT_FILE__ is defined in CMake to provide the file name
// without the path prefix.
#if defined(__SHORT_FILE__)
-#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE) \
- DEBUGLOG_WITH_STREAM_TYPE_AND_FILE(STREAM, TYPE, __SHORT_FILE__)
+#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, LEVEL, TYPE) \
+ DEBUGLOG_WITH_STREAM_TYPE_AND_FILE(STREAM, LEVEL, TYPE, __SHORT_FILE__)
#else
-#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, TYPE) \
+#define DEBUGLOG_WITH_STREAM_AND_TYPE(STREAM, LEVEL, TYPE) \
DEBUGLOG_WITH_STREAM_TYPE_AND_FILE( \
- STREAM, TYPE, ::llvm::impl::LogWithNewline::getShortFileName(__FILE__))
+ STREAM, LEVEL, TYPE, \
+ ::llvm::impl::LogWithNewline::getShortFileName(__FILE__))
#endif
namespace impl {
diff --git a/llvm/lib/Support/Debug.cpp b/llvm/lib/Support/Debug.cpp
index 5bb04d0c22998..1ad758ae9471a 100644
--- a/llvm/lib/Support/Debug.cpp
+++ b/llvm/lib/Support/Debug.cpp
@@ -24,11 +24,13 @@
//===----------------------------------------------------------------------===//
#include "llvm/Support/Debug.h"
+#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/circular_raw_ostream.h"
#include "llvm/Support/raw_ostream.h"
+#include <utility>
#include "DebugOptions.h"
@@ -38,25 +40,46 @@
using namespace llvm;
+/// Parse a debug type string into a pair of the debug type and the debug level.
+/// The expected format is "type[:level]", where the level is an optional
+/// integer.
+static std::pair<std::string, int> parseDebugType(StringRef DbgType) {
+ auto [Type, LevelStr] = DbgType.split(':');
+ int Level;
+ if (!to_integer(LevelStr, Level, 10))
+ Level = 0;
+ return std::make_pair(Type.str(), Level);
+}
+
// Even though LLVM might be built with NDEBUG, define symbols that the code
// built without NDEBUG can depend on via the llvm/Support/Debug.h header.
namespace llvm {
/// Exported boolean set by the -debug option.
bool DebugFlag = false;
-static ManagedStatic<std::vector<std::string>> CurrentDebugType;
+/// The current debug type and an optional debug level.
+/// The debug level is the verbosity of the debug output.
+/// The default level is 0, which is the most verbose.
+/// The level can be set to 1, 2, 3, etc. to control the verbosity of the
+/// output. The level can be set to -1 to disable the output.
+static ManagedStatic<std::vector<std::pair<std::string, int>>> CurrentDebugType;
/// Return true if the specified string is the debug type
/// specified on the command line, or if none was specified on the command line
/// with the -debug-only=X option.
-bool isCurrentDebugType(const char *DebugType) {
+bool isCurrentDebugType(const char *DebugType, int Level) {
if (CurrentDebugType->empty())
return true;
// See if DebugType is in list. Note: do not use find() as that forces us to
// unnecessarily create an std::string instance.
for (auto &d : *CurrentDebugType) {
- if (d == DebugType)
- return true;
+ if (d.first == DebugType) {
+ if (d.second < 0)
+ return false;
+ if (d.second == 0)
+ return true;
+ return d.second >= Level;
+ }
}
return false;
}
@@ -73,8 +96,11 @@ void setCurrentDebugType(const char *Type) {
void setCurrentDebugTypes(const char **Types, unsigned Count) {
CurrentDebugType->clear();
- llvm::append_range(*CurrentDebugType, ArrayRef(Types, Count));
+ CurrentDebugType->reserve(Count);
+ for (const char *Type : ArrayRef(Types, Count))
+ CurrentDebugType->push_back(parseDebugType(Type));
}
+
} // namespace llvm
// All Debug.h functionality is a no-op in NDEBUG mode.
@@ -114,10 +140,10 @@ struct DebugOnlyOpt {
if (Val.empty())
return;
DebugFlag = true;
- SmallVector<StringRef,8> dbgTypes;
- StringRef(Val).split(dbgTypes, ',', -1, false);
- for (auto dbgType : dbgTypes)
- CurrentDebugType->push_back(std::string(dbgType));
+ SmallVector<StringRef, 8> DbgTypes;
+ StringRef(Val).split(DbgTypes, ',', -1, false);
+ for (auto DbgType : DbgTypes)
+ CurrentDebugType->push_back(parseDebugType(DbgType));
}
};
} // namespace
@@ -130,7 +156,11 @@ struct CreateDebugOnly {
return new cl::opt<DebugOnlyOpt, true, cl::parser<std::string>>(
"debug-only",
cl::desc("Enable a specific type of debug output (comma separated list "
- "of types)"),
+ "of types using the format \"type[:level]\", where the level "
+ "is an optional integer. The default level is 0, which is the "
+ "most verbose. The level can be set to 1, 2, 3, etc. to "
+ "control the verbosity of the output. The level can be set to "
+ "-1 to disable the output."),
cl::Hidden, cl::value_desc("debug string"),
cl::location(DebugOnlyOptLoc), cl::ValueRequired);
}
diff --git a/llvm/unittests/Support/DebugLogTest.cpp b/llvm/unittests/Support/DebugLogTest.cpp
index c34d888ab4cad..1886c3ef59cfc 100644
--- a/llvm/unittests/Support/DebugLogTest.cpp
+++ b/llvm/unittests/Support/DebugLogTest.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/Support/DebugLog.h"
+#include "llvm/ADT/Sequence.h"
#include "llvm/Support/raw_ostream.h"
#include "gmock/gmock.h"
#include "gtest/gtest.h"
@@ -26,7 +27,7 @@ TEST(DebugLogTest, Basic) {
{
std::string str;
raw_string_ostream os(str);
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, nullptr) << "NoType";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, nullptr) << "NoType";
EXPECT_FALSE(StringRef(os.str()).starts_with('['));
EXPECT_TRUE(StringRef(os.str()).ends_with("NoType\n"));
}
@@ -35,8 +36,8 @@ TEST(DebugLogTest, Basic) {
{
std::string str;
raw_string_ostream os(str);
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << "A";
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << "B";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "A") << "A";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "B") << "B";
EXPECT_TRUE(StringRef(os.str()).starts_with('['));
EXPECT_THAT(os.str(), AllOf(HasSubstr("A\n"), HasSubstr("B\n")));
}
@@ -47,22 +48,39 @@ TEST(DebugLogTest, Basic) {
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";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "A") << "A";
else
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, "A") << "B";
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << "B";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "A") << "B";
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "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();
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "A") << inc();
EXPECT_THAT(count, Eq(1));
- DEBUGLOG_WITH_STREAM_AND_TYPE(os, "B") << inc();
+ DEBUGLOG_WITH_STREAM_AND_TYPE(os, 0, "B") << inc();
EXPECT_THAT(count, Eq(1));
}
}
+TEST(DebugLogTest, BasicWithLevel) {
+ llvm::DebugFlag = true;
+ // We expect A to be always printed, B to be printed only when level is 1 or
+ // below, and C to be never printed.
+ static const char *DT[] = {"A:0", "B:1", "C:-1"};
+
+ setCurrentDebugTypes(DT, 3);
+ std::string str;
+ raw_string_ostream os(str);
+ for (auto type : {"A", "B", "C"})
+ for (int level : llvm::seq<int>(0, 3))
+ DEBUGLOG_WITH_STREAM_TYPE_FILE_AND_LINE(os, level, type, type, level)
+ << level;
+ EXPECT_EQ(os.str(),
+ "[A] A:0 0\n[A] A:1 1\n[A] A:2 2\n[B] B:0 0\n[B] B:1 1\n");
+}
+
TEST(DebugLogTest, StreamPrefix) {
llvm::DebugFlag = true;
static const char *DT[] = {"A", "B"};
More information about the llvm-commits
mailing list