[lld] r321105 - [WebAssembly] Apply data relocations in parallel. NFC.

[Sam Clegg via llvm-commits]

Author: sbc
Date: Tue Dec 19 12:45:15 2017
New Revision: 321105

URL: http://llvm.org/viewvc/llvm-project?rev=321105&view=rev
Log:
[WebAssembly] Apply data relocations in parallel. NFC.

Store data relocations with their respective segment.
This allows relocations to be applied as each segment
is written (and therefore in parallel).

Differential Revision: https://reviews.llvm.org/D41410

Modified:
    lld/trunk/wasm/InputSegment.h
    lld/trunk/wasm/OutputSections.cpp
    lld/trunk/wasm/OutputSections.h
    lld/trunk/wasm/OutputSegment.h

Modified: lld/trunk/wasm/InputSegment.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/InputSegment.h?rev=321105&r1=321104&r2=321105&view=diff
==============================================================================
--- lld/trunk/wasm/InputSegment.h (original)
+++ lld/trunk/wasm/InputSegment.h Tue Dec 19 12:45:15 2017
@@ -21,6 +21,7 @@
 #ifndef LLD_WASM_INPUT_SEGMENT_H
 #define LLD_WASM_INPUT_SEGMENT_H
 
+#include "WriterUtils.h"
 #include "lld/Common/ErrorHandler.h"
 #include "llvm/Object/Wasm.h"
 
@@ -62,6 +63,7 @@ public:
   const WasmSegment *Segment;
   const ObjFile *File;
   std::vector<WasmRelocation> Relocations;
+  std::vector<OutputRelocation> OutRelocations;
 
 protected:
   const OutputSegment *OutputSeg = nullptr;

Modified: lld/trunk/wasm/OutputSections.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/OutputSections.cpp?rev=321105&r1=321104&r2=321105&view=diff
==============================================================================
--- lld/trunk/wasm/OutputSections.cpp (original)
+++ lld/trunk/wasm/OutputSections.cpp Tue Dec 19 12:45:15 2017
@@ -109,10 +109,11 @@ static void applyRelocation(uint8_t *Buf
 }
 
 static void applyRelocations(uint8_t *Buf, ArrayRef<OutputRelocation> Relocs) {
+  if (!Relocs.size())
+    return;
   log("applyRelocations: count=" + Twine(Relocs.size()));
-  for (const OutputRelocation &Reloc : Relocs) {
+  for (const OutputRelocation &Reloc : Relocs)
     applyRelocation(Buf, Reloc);
-  }
 }
 
 // Relocations contain an index into the function, global or table index
@@ -251,8 +252,7 @@ void CodeSection::writeTo(uint8_t *Buf)
            PayloadSize);
 
     log("applying relocations for: " + File->getName());
-    if (File->CodeRelocations.size())
-      applyRelocations(ContentsStart, File->CodeRelocations);
+    applyRelocations(ContentsStart, File->CodeRelocations);
   });
 }
 
@@ -288,13 +288,13 @@ DataSection::DataSection(ArrayRef<Output
     Segment->setSectionOffset(BodySize);
     BodySize += Segment->Header.size();
     log("Data segment: size=" + Twine(Segment->Size));
-    for (const InputSegment *InputSeg : Segment->InputSegments) {
+    for (InputSegment *InputSeg : Segment->InputSegments) {
       uint32_t InputOffset = InputSeg->getInputSectionOffset();
       uint32_t OutputOffset = Segment->getSectionOffset() +
                               Segment->Header.size() +
                               InputSeg->getOutputSegmentOffset();
-      calcRelocations(*InputSeg->File, InputSeg->Relocations, Relocations,
-                      OutputOffset - InputOffset);
+      calcRelocations(*InputSeg->File, InputSeg->Relocations,
+                      InputSeg->OutRelocations, OutputOffset - InputOffset);
     }
     BodySize += Segment->Size;
   }
@@ -327,13 +327,22 @@ void DataSection::writeTo(uint8_t *Buf)
       memcpy(SegStart + Segment->Header.size() +
                  Input->getOutputSegmentOffset(),
              Content.data(), Content.size());
+      applyRelocations(ContentsStart, Input->OutRelocations);
     }
   });
+}
 
-  applyRelocations(ContentsStart, Relocations);
+uint32_t DataSection::numRelocations() const {
+  uint32_t Count = 0;
+  for (const OutputSegment *Seg : Segments)
+    for (const InputSegment *InputSeg : Seg->InputSegments)
+      Count += InputSeg->OutRelocations.size();
+  return Count;
 }
 
 void DataSection::writeRelocations(raw_ostream &OS) const {
-  for (const OutputRelocation &Reloc : Relocations)
-    writeReloc(OS, Reloc);
+  for (const OutputSegment *Seg : Segments)
+    for (const InputSegment *InputSeg : Seg->InputSegments)
+      for (const OutputRelocation &Reloc : InputSeg->OutRelocations)
+        writeReloc(OS, Reloc);
 }

Modified: lld/trunk/wasm/OutputSections.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/OutputSections.h?rev=321105&r1=321104&r2=321105&view=diff
==============================================================================
--- lld/trunk/wasm/OutputSections.h (original)
+++ lld/trunk/wasm/OutputSections.h Tue Dec 19 12:45:15 2017
@@ -126,11 +126,10 @@ public:
   explicit DataSection(ArrayRef<OutputSegment *> Segments);
   size_t getSize() const override { return Header.size() + BodySize; }
   void writeTo(uint8_t *Buf) override;
-  uint32_t numRelocations() const override { return Relocations.size(); }
+  uint32_t numRelocations() const override;
   void writeRelocations(raw_ostream &OS) const override;
 
 protected:
-  std::vector<OutputRelocation> Relocations;
   ArrayRef<OutputSegment *> Segments;
   std::string DataSectionHeader;
   size_t BodySize = 0;

Modified: lld/trunk/wasm/OutputSegment.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/wasm/OutputSegment.h?rev=321105&r1=321104&r2=321105&view=diff
==============================================================================
--- lld/trunk/wasm/OutputSegment.h (original)
+++ lld/trunk/wasm/OutputSegment.h Tue Dec 19 12:45:15 2017
@@ -38,7 +38,7 @@ public:
   StringRef Name;
   uint32_t Alignment = 0;
   uint32_t StartVA = 0;
-  std::vector<const InputSegment *> InputSegments;
+  std::vector<InputSegment *> InputSegments;
 
   // Sum of the size of the all the input segments
   uint32_t Size = 0;