[Mlir-commits] [llvm] [mlir] [MLIR] Update GreedyRewriter to use the LDBG() debug log mechanism (NFC) (PR #153961)
Mehdi Amini
llvmlistbot at llvm.org
Sun Aug 17 03:12:54 PDT 2025
https://github.com/joker-eph updated https://github.com/llvm/llvm-project/pull/153961
>From 4d25e59b03c622434b42b65c1f6de165771ac4e1 Mon Sep 17 00:00:00 2001
From: Mehdi Amini <joker.eph at gmail.com>
Date: Sat, 16 Aug 2025 08:22:28 -0700
Subject: [PATCH] [MLIR] Update GreedyRewriter to use the LDBG() debug log
mechanism (NFC)
Also improve a bit the doc in the LDBG() implementation
---
llvm/include/llvm/Support/DebugLog.h | 39 +++++++++----------
llvm/unittests/Support/DebugLogTest.cpp | 14 ++++++-
.../Transforms/Utils/DialectConversion.cpp | 4 +-
.../Utils/GreedyPatternRewriteDriver.cpp | 29 +++++++-------
4 files changed, 48 insertions(+), 38 deletions(-)
diff --git a/llvm/include/llvm/Support/DebugLog.h b/llvm/include/llvm/Support/DebugLog.h
index a94e578c0aa1e..ead5dd2a4e8bd 100644
--- a/llvm/include/llvm/Support/DebugLog.h
+++ b/llvm/include/llvm/Support/DebugLog.h
@@ -71,11 +71,10 @@ namespace llvm {
for (bool _c = \
(::llvm::DebugFlag && ::llvm::isCurrentDebugType(TYPE, LEVEL)); \
_c; _c = false) \
- for (::llvm::impl::RAIINewLineStream NewLineStream{(STREAM)}; _c; \
- _c = false) \
- ::llvm::impl::raw_ldbg_ostream{ \
- ::llvm::impl::computePrefix(TYPE, FILE, LINE, LEVEL), NewLineStream} \
- .asLvalue()
+ for (::llvm::impl::raw_ldbg_ostream LdbgOS{ \
+ ::llvm::impl::computePrefix(TYPE, FILE, LINE, LEVEL), (STREAM)}; \
+ _c; _c = false) \
+ ::llvm::impl::RAIINewLineStream{LdbgOS}.asLvalue()
#define DEBUGLOG_WITH_STREAM_TYPE_AND_FILE(STREAM, LEVEL, TYPE, FILE) \
DEBUGLOG_WITH_STREAM_TYPE_FILE_AND_LINE(STREAM, LEVEL, TYPE, FILE, __LINE__)
@@ -89,22 +88,22 @@ namespace impl {
class LLVM_ABI raw_ldbg_ostream final : public raw_ostream {
std::string Prefix;
raw_ostream &Os;
- bool HasPendingNewline;
+ bool ShouldPrefixNextString;
/// Split the line on newlines and insert the prefix before each
/// newline. Forward everything to the underlying stream.
void write_impl(const char *Ptr, size_t Size) final {
auto Str = StringRef(Ptr, Size);
- // Handle the initial prefix.
- if (!Str.empty())
- writeWithPrefix(StringRef());
-
auto Eol = Str.find('\n');
+ // Handle `\n` occurring in the string, ensure to print the prefix at the
+ // beginning of each line.
while (Eol != StringRef::npos) {
+ // Take the line up to the newline (including the newline).
StringRef Line = Str.take_front(Eol + 1);
if (!Line.empty())
writeWithPrefix(Line);
- HasPendingNewline = true;
+ // We printed a newline, record here to print a prefix.
+ ShouldPrefixNextString = true;
Str = Str.drop_front(Eol + 1);
Eol = Str.find('\n');
}
@@ -113,24 +112,21 @@ class LLVM_ABI raw_ldbg_ostream final : public raw_ostream {
}
void emitPrefix() { Os.write(Prefix.c_str(), Prefix.size()); }
void writeWithPrefix(StringRef Str) {
- flushEol();
+ if (ShouldPrefixNextString) {
+ emitPrefix();
+ ShouldPrefixNextString = false;
+ }
Os.write(Str.data(), Str.size());
}
public:
explicit raw_ldbg_ostream(std::string Prefix, raw_ostream &Os,
- bool HasPendingNewline = true)
+ bool ShouldPrefixNextString = true)
: Prefix(std::move(Prefix)), Os(Os),
- HasPendingNewline(HasPendingNewline) {
+ ShouldPrefixNextString(ShouldPrefixNextString) {
SetUnbuffered();
}
- ~raw_ldbg_ostream() final { flushEol(); }
- void flushEol() {
- if (HasPendingNewline) {
- emitPrefix();
- HasPendingNewline = false;
- }
- }
+ ~raw_ldbg_ostream() final {}
/// Forward the current_pos method to the underlying stream.
uint64_t current_pos() const final { return Os.tell(); }
@@ -149,6 +145,7 @@ class RAIINewLineStream final : public raw_ostream {
~RAIINewLineStream() { Os << '\n'; }
void write_impl(const char *Ptr, size_t Size) final { Os.write(Ptr, Size); }
uint64_t current_pos() const final { return Os.tell(); }
+ RAIINewLineStream &asLvalue() { return *this; }
};
/// Remove the path prefix from the file name.
diff --git a/llvm/unittests/Support/DebugLogTest.cpp b/llvm/unittests/Support/DebugLogTest.cpp
index b28c59cf2bdd5..40bed5141d18b 100644
--- a/llvm/unittests/Support/DebugLogTest.cpp
+++ b/llvm/unittests/Support/DebugLogTest.cpp
@@ -115,8 +115,18 @@ TEST(DebugLogTest, StreamPrefix) {
ldbg_osA << "5";
EXPECT_EQ(os.str(), expected);
}
- // After destructors, there was a pending newline for stream B.
- EXPECT_EQ(os.str(), expected + "PrefixB ");
+ EXPECT_EQ(os.str(), expected);
+}
+
+TEST(DebugLogTest, DestructorPrefix) {
+ llvm::DebugFlag = true;
+ std::string str;
+ raw_string_ostream os(str);
+ {
+ llvm::impl::raw_ldbg_ostream ldbg_osB("PrefixB ", os);
+ }
+ // After destructors, nothing should have been printed.
+ EXPECT_EQ(os.str(), "");
}
#else
TEST(DebugLogTest, Basic) {
diff --git a/mlir/lib/Transforms/Utils/DialectConversion.cpp b/mlir/lib/Transforms/Utils/DialectConversion.cpp
index ff34a58965763..2877090354588 100644
--- a/mlir/lib/Transforms/Utils/DialectConversion.cpp
+++ b/mlir/lib/Transforms/Utils/DialectConversion.cpp
@@ -1138,8 +1138,8 @@ struct ConversionPatternRewriterImpl : public RewriterBase::Listener {
SmallPtrSet<Operation *, 1> pendingRootUpdates;
/// A raw output stream used to prefix the debug log.
- llvm::impl::raw_ldbg_ostream os{(Twine("[") + DEBUG_TYPE + "] ").str(),
- llvm::dbgs(), /*HasPendingNewline=*/false};
+ llvm::impl::raw_ldbg_ostream os{(Twine("[") + DEBUG_TYPE + ":1] ").str(),
+ llvm::dbgs()};
/// A logger used to emit diagnostics during the conversion process.
llvm::ScopedPrinter logger{os};
diff --git a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
index 607b86cb86315..7197ddf553b5b 100644
--- a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
+++ b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
@@ -15,6 +15,8 @@
#include "mlir/Config/mlir-config.h"
#include "mlir/IR/Action.h"
#include "mlir/IR/Matchers.h"
+#include "mlir/IR/Operation.h"
+#include "mlir/IR/OperationSupport.h"
#include "mlir/IR/Verifier.h"
#include "mlir/Interfaces/SideEffectInterfaces.h"
#include "mlir/Rewrite/PatternApplicator.h"
@@ -23,7 +25,7 @@
#include "llvm/ADT/BitVector.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/ScopeExit.h"
-#include "llvm/Support/Debug.h"
+#include "llvm/Support/DebugLog.h"
#include "llvm/Support/ScopedPrinter.h"
#include "llvm/Support/raw_ostream.h"
@@ -178,9 +180,8 @@ static Operation *getDumpRootOp(Operation *op) {
return op;
}
static void logSuccessfulFolding(Operation *op) {
- llvm::dbgs() << "// *** IR Dump After Successful Folding ***\n";
- op->dump();
- llvm::dbgs() << "\n\n";
+ LDBG() << "// *** IR Dump After Successful Folding ***\n"
+ << OpWithFlags(op, OpPrintingFlags().elideLargeElementsAttrs());
}
#endif // NDEBUG
@@ -394,8 +395,12 @@ class GreedyPatternRewriteDriver : public RewriterBase::Listener {
function_ref<void(Diagnostic &)> reasonCallback) override;
#ifndef NDEBUG
+ /// A raw output stream used to prefix the debug log.
+
+ llvm::impl::raw_ldbg_ostream os{(Twine("[") + DEBUG_TYPE + ":1] ").str(),
+ llvm::dbgs()};
/// A logger used to emit information during the application process.
- llvm::ScopedPrinter logger{llvm::dbgs()};
+ llvm::ScopedPrinter logger{os};
#endif
/// The low-level pattern applicator.
@@ -917,10 +922,9 @@ mlir::applyPatternsGreedily(Region ®ion,
RegionPatternRewriteDriver driver(region.getContext(), patterns, config,
region);
LogicalResult converged = std::move(driver).simplify(changed);
- LLVM_DEBUG(if (failed(converged)) {
- llvm::dbgs() << "The pattern rewrite did not converge after scanning "
- << config.getMaxIterations() << " times\n";
- });
+ if (failed(converged))
+ LDBG() << "The pattern rewrite did not converge after scanning "
+ << config.getMaxIterations() << " times\n";
return converged;
}
@@ -1052,9 +1056,8 @@ LogicalResult mlir::applyOpPatternsGreedily(
LogicalResult converged = std::move(driver).simplify(ops, changed);
if (allErased)
*allErased = surviving.empty();
- LLVM_DEBUG(if (failed(converged)) {
- llvm::dbgs() << "The pattern rewrite did not converge after "
- << config.getMaxNumRewrites() << " rewrites";
- });
+ if (failed(converged))
+ LDBG() << "The pattern rewrite did not converge after "
+ << config.getMaxNumRewrites() << " rewrites";
return converged;
}
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