https://github.com/OCHyams created
https://github.com/llvm/llvm-project/pull/133478
The waterline is managed through DILocation creation,
LLVMContext::incNextAtomGroup, and LLVMContext::updateAtomGroupWaterline.
Add unittest.
>From d12e993d5e22cae5c6eeb7088eedbf8e3ec2cb98 Mon Sep 17 00:00:00 2001
From: Orlando Cazalet-Hyams <orlando.hy...@sony.com>
Date: Tue, 18 Mar 2025 16:50:17 +0000
Subject: [PATCH] [KeyInstr] Add Atom Group waterline to LLVMContext
The waterline is managed through DILocation creation,
LLVMContext::incNextAtomGroup, and LLVMContext::updateAtomGroupWaterline.
Add unittest.
---
llvm/include/llvm/IR/LLVMContext.h | 8 +++++++
llvm/lib/IR/DebugInfoMetadata.cpp | 3 +++
llvm/lib/IR/LLVMContext.cpp | 8 +++++++
llvm/lib/IR/LLVMContextImpl.h | 10 ++++++++
llvm/unittests/IR/MetadataTest.cpp | 38 ++++++++++++++++++++++++++++++
5 files changed, 67 insertions(+)
diff --git a/llvm/include/llvm/IR/LLVMContext.h
b/llvm/include/llvm/IR/LLVMContext.h
index bbd125fd38cf1..d3cdd31e0b12f 100644
--- a/llvm/include/llvm/IR/LLVMContext.h
+++ b/llvm/include/llvm/IR/LLVMContext.h
@@ -335,6 +335,14 @@ class LLVMContext {
StringRef getDefaultTargetFeatures();
void setDefaultTargetFeatures(StringRef Features);
+ /// Key Instructions: update the highest number atom group emitted for any
+ /// function.
+ void updateAtomGroupWaterline(uint64_t G);
+
+ /// Key Instructions: get the next free atom group number and increment
+ /// the global tracker.
+ uint64_t incNextAtomGroup();
+
private:
// Module needs access to the add/removeModule methods.
friend class Module;
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp
b/llvm/lib/IR/DebugInfoMetadata.cpp
index f4f9fca38945c..aefda2f7be0b0 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -67,6 +67,9 @@ DILocation::DILocation(LLVMContext &C, StorageType Storage,
unsigned Line,
#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
assert(AtomRank <= 7 && "AtomRank number should fit in 3 bits");
#endif
+ if (AtomRank)
+ C.updateAtomGroupWaterline(AtomGroup + 1);
+
assert((MDs.size() == 1 || MDs.size() == 2) &&
"Expected a scope and optional inlined-at");
// Set line and column.
diff --git a/llvm/lib/IR/LLVMContext.cpp b/llvm/lib/IR/LLVMContext.cpp
index 447e5d92e0b99..4781085b30431 100644
--- a/llvm/lib/IR/LLVMContext.cpp
+++ b/llvm/lib/IR/LLVMContext.cpp
@@ -377,3 +377,11 @@ StringRef LLVMContext::getDefaultTargetFeatures() {
void LLVMContext::setDefaultTargetFeatures(StringRef Features) {
pImpl->DefaultTargetFeatures = Features;
}
+
+void LLVMContext::updateAtomGroupWaterline(uint64_t V) {
+ pImpl->NextAtomGroup = std::max(pImpl->NextAtomGroup, V);
+}
+
+uint64_t LLVMContext::incNextAtomGroup() {
+ return pImpl->NextAtomGroup++;
+}
diff --git a/llvm/lib/IR/LLVMContextImpl.h b/llvm/lib/IR/LLVMContextImpl.h
index 99f0d8837de52..5a52d41834095 100644
--- a/llvm/lib/IR/LLVMContextImpl.h
+++ b/llvm/lib/IR/LLVMContextImpl.h
@@ -1832,6 +1832,16 @@ class LLVMContextImpl {
std::string DefaultTargetCPU;
std::string DefaultTargetFeatures;
+
+ /// The next available source atom group number. The front end is responsible
+ /// for assigning source atom numbers, but certain optimisations need to
+ /// assign new group numbers to a set of instructions. Most often code
+ /// duplication optimisations like loop unroll. Tracking a global maximum
+ /// value means we can know (cheaply) we're never using a group number that's
+ /// already used within this function.
+ ///
+ /// Start a 1 because 0 means the source location isn't part of an atom
group.
+ uint64_t NextAtomGroup = 1;
};
} // end namespace llvm
diff --git a/llvm/unittests/IR/MetadataTest.cpp
b/llvm/unittests/IR/MetadataTest.cpp
index 94cebb0406598..8a1c1f9d306c6 100644
--- a/llvm/unittests/IR/MetadataTest.cpp
+++ b/llvm/unittests/IR/MetadataTest.cpp
@@ -6,6 +6,7 @@
//
//===----------------------------------------------------------------------===//
+#include "../lib/IR/LLVMContextImpl.h"
#include "llvm/IR/Metadata.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLExtras.h"
@@ -1366,6 +1367,43 @@ TEST_F(DILocationTest, discriminatorSpecialCases) {
EXPECT_EQ(std::nullopt, L4->cloneByMultiplyingDuplicationFactor(0x1000));
}
+TEST_F(DILocationTest, KeyInstructions) {
+ Context.pImpl->NextAtomGroup = 1;
+
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 1u);
+ DILocation *A1 = DILocation::get(Context, 1, 0, getSubprogram(), nullptr,
false, 1, 2);
+ // The group is only applied to the DILocation if the build has opted into
+ // the additional DILocation fields needed for the feature.
+#ifdef EXPERIMENTAL_KEY_INSTRUCTIONS
+ EXPECT_EQ(A1->getAtomGroup(), 1u);
+ EXPECT_EQ(A1->getAtomRank(), 2u);
+#else
+ EXPECT_EQ(A1->getAtomGroup(), 0u);
+ EXPECT_EQ(A1->getAtomRank(), 0u);
+#endif
+
+ // Group number 1 has been "used" so next available is 2.
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 2u);
+
+ // Set a group number higher than current + 1, then check the waterline.
+ DILocation::get(Context, 2, 0, getSubprogram(), nullptr, false, 5, 1);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 6u);
+
+ // The waterline should be unchanged (group <= next).
+ DILocation::get(Context, 3, 0, getSubprogram(), nullptr, false, 4, 1);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 6u);
+ DILocation::get(Context, 3, 0, getSubprogram(), nullptr, false, 5, 1);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 6u);
+
+ // Check the waterline gets incremented by 1.
+ EXPECT_EQ(Context.incNextAtomGroup(), 6u);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 7u);
+
+ Context.updateAtomGroupWaterline(8);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 8u);
+ Context.updateAtomGroupWaterline(7);
+ EXPECT_EQ(Context.pImpl->NextAtomGroup, 8u);
+}
typedef MetadataTest GenericDINodeTest;
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