Draft extracting CGAtomic to LLVMFrontend

.git-blame-ignore-revs

@@ -84,3 +84,6 @@ b9079baaddfed5e604fbfaa1d81a7a1c38e78c26
 
 # [libc++][NFC] Run clang-format on libcxx/include again (#95874)
 e2c2ffbe7a1b5d9e32a2ce64279475b50c4cba5b
+
+# [lldb][nfc] Deindent ProcessGDBRemote::SetThreadStopInfo by two levels
+b32931c5b32eb0d2cf37d688b34f8548c9674c19

.github/CODEOWNERS

@@ -67,11 +67,11 @@ clang/test/AST/Interp/ @tbaederr
 /mlir/include/mlir/Dialect/Linalg @dcaballe @nicolasvasilache @rengolin
 /mlir/lib/Dialect/Linalg @dcaballe @nicolasvasilache @rengolin
 /mlir/lib/Dialect/Linalg/Transforms/DecomposeLinalgOps.cpp @MaheshRavishankar @nicolasvasilache
-/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp @MaheshRavishankar @nicolasvasilache
+/mlir/lib/Dialect/Linalg/Transforms/DropUnitDims.cpp @dcaballe @MaheshRavishankar @nicolasvasilache
 /mlir/lib/Dialect/Linalg/Transforms/ElementwiseOpFusion.cpp @MaheshRavishankar @nicolasvasilache
 /mlir/lib/Dialect/Linalg/Transforms/DataLayoutPropagation.cpp @hanhanW @nicolasvasilache
-/mlir/lib/Dialect/Linalg/Transforms/Transforms.cpp @hanhanW @nicolasvasilache
-/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp @hanhanW @nicolasvasilache
+/mlir/lib/Dialect/Linalg/Transforms/Transforms.cpp @dcaballe @hanhanW @nicolasvasilache
+/mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp @banach-space @dcaballe @hanhanW @nicolasvasilache
 
 # MemRef Dialect in MLIR.
 /mlir/lib/Dialect/MemRef/Transforms/EmulateNarrowType.cpp @MaheshRavishankar @nicolasvasilache
@@ -85,10 +85,10 @@ clang/test/AST/Interp/ @tbaederr
 /mlir/**/*VectorToSCF* @banach-space @dcaballe @matthias-springer @nicolasvasilache
 /mlir/**/*VectorToLLVM* @banach-space @dcaballe @nicolasvasilache
 /mlir/**/*X86Vector* @aartbik @dcaballe @nicolasvasilache
-/mlir/include/mlir/Dialect/Vector @dcaballe @nicolasvasilache
-/mlir/lib/Dialect/Vector @dcaballe @nicolasvasilache
-/mlir/lib/Dialect/Vector/Transforms/* @hanhanW @nicolasvasilache
-/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp @MaheshRavishankar @nicolasvasilache
+/mlir/include/mlir/Dialect/Vector @banach-space @dcaballe @nicolasvasilache
+/mlir/lib/Dialect/Vector @banach-space @dcaballe @nicolasvasilache
+/mlir/lib/Dialect/Vector/Transforms/* @banach-space @dcaballe @hanhanW @nicolasvasilache
+/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp @banach-space @dcaballe @MaheshRavishankar @nicolasvasilache
 /mlir/**/*EmulateNarrowType* @dcaballe @hanhanW
 
 # Presburger library in MLIR

bolt/docs/CommandLineArgumentReference.md

@@ -283,6 +283,12 @@
 
   List of functions to pad with amount of bytes
 
+- `--print-mappings`
+
+  Print mappings in the legend, between characters/blocks and text sections
+  (default false).
+
+
 - `--profile-format=<value>`
 
   Format to dump profile output in aggregation mode, default is fdata
@@ -1240,4 +1246,4 @@
 
 - `--print-options`
 
-  Print non-default options after command line parsing
+  Print non-default options after command line parsing

bolt/docs/Heatmaps.md

@@ -1,9 +1,9 @@
 # Code Heatmaps
 
 BOLT has gained the ability to print code heatmaps based on
-sampling-based LBR profiles generated by `perf`. The output is produced
-in colored ASCII to be displayed in a color-capable terminal. It looks
-something like this:
+sampling-based profiles generated by `perf`, either with `LBR` data or not.
+The output is produced in colored ASCII to be displayed in a color-capable
+terminal. It looks something like this:
 
 ![](./Heatmap.png)
 
@@ -32,20 +32,64 @@ $ llvm-bolt-heatmap -p perf.data <executable>
 ```
 
 By default the heatmap will be dumped to *stdout*. You can change it
-with `-o <heatmapfile>` option. Each character/block in the heatmap
-shows the execution data accumulated for corresponding 64 bytes of
-code. You can change this granularity with a `-block-size` option.
-E.g. set it to 4096 to see code usage grouped by 4K pages.
-Other useful options are:
+with `-o <heatmapfile>` option.
 
-```bash
--line-size=<uint>   - number of entries per line (default 256)
--max-address=<uint> - maximum address considered valid for heatmap (default 4GB)
-```
 
 If you prefer to look at the data in a browser (or would like to share
 it that way), then you can use an HTML conversion tool. E.g.:
 
 ```bash
 $ aha -b -f <heatmapfile> > <heatmapfile>.html
 ```
+
+---
+
+## Background on heatmaps:
+A heatmap is effectively a histogram that is rendered into a grid for better
+visualization.
+In theory we can generate a heatmap using any binary and a perf profile.
+
+Each block/character in the heatmap shows the execution data accumulated for
+corresponding 64 bytes of code. You can change this granularity with a
+`-block-size` option.
+E.g. set it to 4096 to see code usage grouped by 4K pages.
+
+
+When a block is shown as a dot, it means that no samples were found for that
+address.
+When it is shown as a letter, it indicates a captured sample on a particular
+text section of the binary.
+To show a mapping between letters and text sections in the legend, use
+`-print-mappings`.
+When a sampled address does not belong to any of the text sections, the
+characters 'o' or 'O' will be shown.
+
+The legend shows by default the ranges in the heatmap according to the number
+of samples per block.
+A color is assigned per range, except the first two ranges that distinguished by
+lower and upper case letters.
+
+On the Y axis, each row/line starts with an actual address of the binary.
+Consecutive lines in the heatmap advance by the same amount, with the binary
+size covered by a line dependent on the block size and the line size.
+An empty new line is inserted for larger gaps between samples.
+
+On the X axis, the horizontally emitted hex numbers can help *estimate* where
+in the line the samples lie, but they cannot be combined to provide a full
+address, as they are relative to both the bucket and line sizes.
+
+In the example below, the highlighted `0x100` column is not an offset to each
+row's address, but instead, it points to the middle of the line.
+For the generation, the default bucket size was used with a line size of 128.
+
+
+![](./HeatmapHeader.png)
+
+
+Some useful options are:
+
+```
+-line-size=<uint>   - number of entries per line (default 256)
+-max-address=<uint> - maximum address considered valid for heatmap (default 4GB)
+-print-mappings     - print mappings in the legend, between characters/blocks and text sections (default false)
+```

bolt/include/bolt/Core/DIEBuilder.h

@@ -135,13 +135,6 @@ class DIEBuilder {
 
   /// Returns current state of the DIEBuilder
   State &getState() { return *BuilderState.get(); }
-  /// Resolve the reference in DIE, if target is not loaded into IR,
-  /// pre-allocate it. \p RefCU will be updated to the Unit specific by \p
-  /// RefValue.
-  DWARFDie resolveDIEReference(
-      const DWARFFormValue &RefValue,
-      const DWARFAbbreviationDeclaration::AttributeSpec AttrSpec,
-      DWARFUnit *&RefCU, DWARFDebugInfoEntry &DwarfDebugInfoEntry);
 
   /// Resolve the reference in DIE, if target is not loaded into IR,
   /// pre-allocate it. \p RefCU will be updated to the Unit specific by \p
@@ -165,10 +158,9 @@ class DIEBuilder {
       const DWARFFormValue &Val);
 
   /// Clone an attribute in reference format.
-  void cloneDieReferenceAttribute(
+  void cloneDieOffsetReferenceAttribute(
       DIE &Die, const DWARFUnit &U, const DWARFDie &InputDIE,
-      const DWARFAbbreviationDeclaration::AttributeSpec AttrSpec,
-      const DWARFFormValue &Val);
+      const DWARFAbbreviationDeclaration::AttributeSpec AttrSpec, uint64_t Ref);
 
   /// Clone an attribute in block format.
   void cloneBlockAttribute(

bolt/include/bolt/Core/DebugData.h

@@ -256,7 +256,7 @@ class DebugRangeListsSectionWriter : public DebugRangesSectionWriter {
   };
   virtual ~DebugRangeListsSectionWriter(){};
 
-  static void setAddressWriter(DebugAddrWriter *AddrW) { AddrWriter = AddrW; }
+  void setAddressWriter(DebugAddrWriter *AddrW) { AddrWriter = AddrW; }
 
   /// Add ranges with caching.
   uint64_t addRanges(
@@ -284,7 +284,7 @@ class DebugRangeListsSectionWriter : public DebugRangesSectionWriter {
   }
 
 private:
-  static DebugAddrWriter *AddrWriter;
+  DebugAddrWriter *AddrWriter = nullptr;
   /// Used to find unique CU ID.
   DWARFUnit *CU;
   /// Current relative offset of range list entry within this CUs rangelist
@@ -336,21 +336,36 @@ using AddressSectionBuffer = SmallVector<char, 4>;
 class DebugAddrWriter {
 public:
   DebugAddrWriter() = delete;
-  DebugAddrWriter(BinaryContext *BC_);
+  DebugAddrWriter(BinaryContext *BC_) : DebugAddrWriter(BC_, UCHAR_MAX) {};
+  DebugAddrWriter(BinaryContext *BC_, uint8_t AddressByteSize);
   virtual ~DebugAddrWriter(){};
   /// Given an address returns an index in .debug_addr.
   /// Adds Address to map.
   uint32_t getIndexFromAddress(uint64_t Address, DWARFUnit &CU);
 
   /// Write out entries in to .debug_addr section for CUs.
-  virtual void update(DIEBuilder &DIEBlder, DWARFUnit &CUs);
+  virtual std::optional<uint64_t> finalize(const size_t BufferSize);
 
   /// Return buffer with all the entries in .debug_addr already writen out using
   /// update(...).
-  virtual AddressSectionBuffer &finalize() { return *Buffer; }
+  virtual std::unique_ptr<AddressSectionBuffer> releaseBuffer() {
+    return std::move(Buffer);
+  }
+
+  /// Returns buffer size.
+  virtual size_t getBufferSize() const { return Buffer->size(); }
+
+  /// Returns True if Buffer is not empty.
+  bool isInitialized() const { return !Buffer->empty(); }
 
-  /// Returns False if .debug_addr section was created..
-  bool isInitialized() const { return !AddressMaps.empty(); }
+  /// Updates address base with the given Offset.
+  virtual void updateAddrBase(DIEBuilder &DIEBlder, DWARFUnit &CU,
+                              const uint64_t Offset);
+
+  /// Appends an AddressSectionBuffer to the address writer's buffer.
+  void appendToAddressBuffer(const AddressSectionBuffer &Buffer) {
+    *AddressStream << Buffer;
+  }
 
 protected:
   class AddressForDWOCU {
@@ -407,23 +422,32 @@ class DebugAddrWriter {
   }
 
   BinaryContext *BC;
-  /// Maps DWOID to AddressForDWOCU.
-  std::unordered_map<uint64_t, AddressForDWOCU> AddressMaps;
+  /// Address for the DWO CU associated with the address writer.
+  AddressForDWOCU Map;
+  uint8_t AddressByteSize;
   /// Mutex used for parallel processing of debug info.
   std::mutex WriterMutex;
   std::unique_ptr<AddressSectionBuffer> Buffer;
   std::unique_ptr<raw_svector_ostream> AddressStream;
   /// Used to track sections that were not modified so that they can be re-used.
-  DenseMap<uint64_t, uint64_t> UnmodifiedAddressOffsets;
+  static DenseMap<uint64_t, uint64_t> UnmodifiedAddressOffsets;
 };
 
 class DebugAddrWriterDwarf5 : public DebugAddrWriter {
 public:
   DebugAddrWriterDwarf5() = delete;
   DebugAddrWriterDwarf5(BinaryContext *BC) : DebugAddrWriter(BC) {}
+  DebugAddrWriterDwarf5(BinaryContext *BC, uint8_t AddressByteSize,
+                        std::optional<uint64_t> AddrOffsetSectionBase)
+      : DebugAddrWriter(BC, AddressByteSize),
+        AddrOffsetSectionBase(AddrOffsetSectionBase) {}
 
   /// Write out entries in to .debug_addr section for CUs.
-  virtual void update(DIEBuilder &DIEBlder, DWARFUnit &CUs) override;
+  virtual std::optional<uint64_t> finalize(const size_t BufferSize) override;
+
+  /// Updates address base with the given Offset.
+  virtual void updateAddrBase(DIEBuilder &DIEBlder, DWARFUnit &CU,
+                              const uint64_t Offset) override;
 
 protected:
   /// Given DWARFUnit \p Unit returns either DWO ID or it's offset within
@@ -435,6 +459,10 @@ class DebugAddrWriterDwarf5 : public DebugAddrWriter {
     }
     return Unit.getOffset();
   }
+
+private:
+  std::optional<uint64_t> AddrOffsetSectionBase = std::nullopt;
+  static constexpr uint32_t HeaderSize = 8;
 };
 
 /// This class is NOT thread safe.
@@ -583,12 +611,10 @@ class DebugLoclistWriter : public DebugLocWriter {
 public:
   ~DebugLoclistWriter() {}
   DebugLoclistWriter() = delete;
-  DebugLoclistWriter(DWARFUnit &Unit, uint8_t DV, bool SD)
-      : DebugLocWriter(DV, LocWriterKind::DebugLoclistWriter), CU(Unit),
-        IsSplitDwarf(SD) {
-    assert(DebugLoclistWriter::AddrWriter &&
-           "Please use SetAddressWriter to initialize "
-           "DebugAddrWriter before instantiation.");
+  DebugLoclistWriter(DWARFUnit &Unit, uint8_t DV, bool SD,
+                     DebugAddrWriter &AddrW)
+      : DebugLocWriter(DV, LocWriterKind::DebugLoclistWriter),
+        AddrWriter(AddrW), CU(Unit), IsSplitDwarf(SD) {
     if (DwarfVersion >= 5) {
       LocBodyBuffer = std::make_unique<DebugBufferVector>();
       LocBodyStream = std::make_unique<raw_svector_ostream>(*LocBodyBuffer);
@@ -600,8 +626,6 @@ class DebugLoclistWriter : public DebugLocWriter {
     }
   }
 
-  static void setAddressWriter(DebugAddrWriter *AddrW) { AddrWriter = AddrW; }
-
   /// Stores location lists internally to be written out during finalize phase.
   virtual void addList(DIEBuilder &DIEBldr, DIE &Die, DIEValue &AttrInfo,
                        DebugLocationsVector &LocList) override;
@@ -630,7 +654,7 @@ class DebugLoclistWriter : public DebugLocWriter {
   /// Writes out locations in to a local buffer and applies debug info patches.
   void finalizeDWARF5(DIEBuilder &DIEBldr, DIE &Die);
 
-  static DebugAddrWriter *AddrWriter;
+  DebugAddrWriter &AddrWriter;
   DWARFUnit &CU;
   bool IsSplitDwarf{false};
   // Used for DWARF5 to store location lists before being finalized.

bolt/include/bolt/Core/MCPlusBuilder.h

@@ -2041,9 +2041,14 @@ class MCPlusBuilder {
     return InstructionListType();
   }
 
-  virtual InstructionListType createDummyReturnFunction(MCContext *Ctx) const {
-    llvm_unreachable("not implemented");
-    return InstructionListType();
+  /// Returns a function body that contains only a return instruction. An
+  /// example usage is a workaround for the '__bolt_fini_trampoline' of
+  // Instrumentation.
+  virtual InstructionListType
+  createReturnInstructionList(MCContext *Ctx) const {
+    InstructionListType Insts(1);
+    createReturn(Insts[0]);
+    return Insts;
   }
 
   /// This method takes an indirect call instruction and splits it up into an

bolt/include/bolt/Rewrite/DWARFRewriter.h

@@ -66,10 +66,6 @@ class DWARFRewriter {
   /// .debug_aranges DWARF section.
   std::unique_ptr<DebugARangesSectionWriter> ARangesSectionWriter;
 
-  /// Stores and serializes information that will be put into the
-  /// .debug_addr DWARF section.
-  std::unique_ptr<DebugAddrWriter> AddrWriter;
-
   /// Stores and serializes information that will be put in to the
   /// .debug_addr DWARF section.
   /// Does not do de-duplication.
@@ -93,6 +89,10 @@ class DWARFRewriter {
   std::unordered_map<uint64_t, std::unique_ptr<DebugRangesSectionWriter>>
       LegacyRangesWritersByCU;
 
+  /// Stores address writer for each CU.
+  std::unordered_map<uint64_t, std::unique_ptr<DebugAddrWriter>>
+      AddressWritersByCU;
+
   std::mutex LocListDebugInfoPatchesMutex;
 
   /// Dwo id specific its RangesBase.
@@ -115,6 +115,7 @@ class DWARFRewriter {
   void updateUnitDebugInfo(DWARFUnit &Unit, DIEBuilder &DIEBldr,
                            DebugLocWriter &DebugLocWriter,
                            DebugRangesSectionWriter &RangesSectionWriter,
+                           DebugAddrWriter &AddressWriter,
                            std::optional<uint64_t> RangesBase = std::nullopt);
 
   /// Patches the binary for an object's address ranges to be updated.
@@ -141,13 +142,15 @@ class DWARFRewriter {
   /// Process and write out CUs that are passsed in.
   void finalizeCompileUnits(DIEBuilder &DIEBlder, DIEStreamer &Streamer,
                             CUOffsetMap &CUMap,
-                            const std::list<DWARFUnit *> &CUs);
+                            const std::list<DWARFUnit *> &CUs,
+                            DebugAddrWriter &FinalAddrWriter);
 
   /// Finalize debug sections in the main binary.
   void finalizeDebugSections(DIEBuilder &DIEBlder,
                              DWARF5AcceleratorTable &DebugNamesTable,
                              DIEStreamer &Streamer, raw_svector_ostream &ObjOS,
-                             CUOffsetMap &CUMap);
+                             CUOffsetMap &CUMap,
+                             DebugAddrWriter &FinalAddrWriter);
 
   /// Patches the binary for DWARF address ranges (e.g. in functions and lexical
   /// blocks) to be updated.

bolt/include/bolt/Rewrite/RewriteInstance.h

@@ -490,7 +490,7 @@ class RewriteInstance {
   std::unordered_map<const MCSymbol *, uint32_t> SymbolIndex;
 
   /// Store all non-zero symbols in this map for a quick address lookup.
-  std::map<uint64_t, llvm::object::SymbolRef> FileSymRefs;
+  std::multimap<uint64_t, llvm::object::SymbolRef> FileSymRefs;
 
   /// FILE symbols used for disambiguating split function parents.
   std::vector<ELFSymbolRef> FileSymbols;

bolt/include/bolt/Utils/CommandLineOpts.h

@@ -40,6 +40,7 @@ extern llvm::cl::opt<unsigned> ExecutionCountThreshold;
 extern llvm::cl::opt<unsigned> HeatmapBlock;
 extern llvm::cl::opt<unsigned long long> HeatmapMaxAddress;
 extern llvm::cl::opt<unsigned long long> HeatmapMinAddress;
+extern llvm::cl::opt<bool> HeatmapPrintMappings;
 extern llvm::cl::opt<bool> HotData;
 extern llvm::cl::opt<bool> HotFunctionsAtEnd;
 extern llvm::cl::opt<bool> HotText;