[lld] 4c98d08 - [ELF] Speed up MergeInputSection::split*. NFC

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2021-12-16T21:17:02-08:00
New Revision: 4c98d08841e65f2a61382ecd9f06b0d01ffd615a

URL: https://github.com/llvm/llvm-project/commit/4c98d08841e65f2a61382ecd9f06b0d01ffd615a
DIFF: https://github.com/llvm/llvm-project/commit/4c98d08841e65f2a61382ecd9f06b0d01ffd615a.diff

LOG: [ELF] Speed up MergeInputSection::split*. NFC

Added: 
    

Modified: 
    lld/ELF/InputSection.cpp
    lld/ELF/InputSection.h

Removed: 
    


################################################################################
diff  --git a/lld/ELF/InputSection.cpp b/lld/ELF/InputSection.cpp
index b2f63799337e..baceaa780c6e 100644
--- a/lld/ELF/InputSection.cpp
+++ b/lld/ELF/InputSection.cpp
@@ -1365,7 +1365,7 @@ SyntheticSection *MergeInputSection::getParent() const {
 // null-terminated strings.
 void MergeInputSection::splitStrings(ArrayRef<uint8_t> data, size_t entSize) {
   size_t off = 0;
-  bool isAlloc = flags & SHF_ALLOC;
+  const bool live = !(flags & SHF_ALLOC) || !config->gcSections;
   StringRef s = toStringRef(data);
 
   while (!s.empty()) {
@@ -1374,7 +1374,7 @@ void MergeInputSection::splitStrings(ArrayRef<uint8_t> data, size_t entSize) {
       fatal(toString(this) + ": string is not null terminated");
     size_t size = end + entSize;
 
-    pieces.emplace_back(off, xxHash64(s.substr(0, size)), !isAlloc);
+    pieces.emplace_back(off, xxHash64(s.substr(0, size)), live);
     s = s.substr(size);
     off += size;
   }
@@ -1386,10 +1386,10 @@ void MergeInputSection::splitNonStrings(ArrayRef<uint8_t> data,
                                         size_t entSize) {
   size_t size = data.size();
   assert((size % entSize) == 0);
-  bool isAlloc = flags & SHF_ALLOC;
+  const bool live = !(flags & SHF_ALLOC) || !config->gcSections;
 
   for (size_t i = 0; i != size; i += entSize)
-    pieces.emplace_back(i, xxHash64(data.slice(i, entSize)), !isAlloc);
+    pieces.emplace_back(i, xxHash64(data.slice(i, entSize)), live);
 }
 
 template <class ELFT>

diff  --git a/lld/ELF/InputSection.h b/lld/ELF/InputSection.h
index 70bbe4975a38..a5967b500f90 100644
--- a/lld/ELF/InputSection.h
+++ b/lld/ELF/InputSection.h
@@ -250,7 +250,7 @@ class InputSectionBase : public SectionBase {
 // be found by looking at the next one).
 struct SectionPiece {
   SectionPiece(size_t off, uint32_t hash, bool live)
-      : inputOff(off), live(live || !config->gcSections), hash(hash >> 1) {}
+      : inputOff(off), live(live), hash(hash >> 1) {}
 
   uint32_t inputOff;
   uint32_t live : 1;