[PATCH] D50023: Make ICF output deterministic.

[Rui Ueyama via Phabricator via llvm-commits]

ruiu created this revision.
ruiu added a reviewer: pcc.
Herald added subscribers: mgrang, hiraditya, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a reviewer: espindola.

This patch does the same thing as r338153 for COFF.


https://reviews.llvm.org/D50023

Files:
  lld/COFF/ICF.cpp
  lld/ELF/ICF.cpp
  llvm/include/llvm/Support/xxhash.h
  llvm/lib/Support/xxhash.cpp


Index: llvm/lib/Support/xxhash.cpp
===================================================================
--- llvm/lib/Support/xxhash.cpp
+++ llvm/lib/Support/xxhash.cpp
@@ -132,3 +132,7 @@
 
   return H64;
 }
+
+uint64_t llvm::xxHash64(ArrayRef<uint8_t> Data) {
+  return xxHash64({(const char *)Data.data(), Data.size()});
+}
Index: llvm/include/llvm/Support/xxhash.h
===================================================================
--- llvm/include/llvm/Support/xxhash.h
+++ llvm/include/llvm/Support/xxhash.h
@@ -38,10 +38,12 @@
 #ifndef LLVM_SUPPORT_XXHASH_H
 #define LLVM_SUPPORT_XXHASH_H
 
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 
 namespace llvm {
 uint64_t xxHash64(llvm::StringRef Data);
+uint64_t xxHash64(llvm::ArrayRef<uint8_t> Data);
 }
 
 #endif
Index: lld/ELF/ICF.cpp
===================================================================
--- lld/ELF/ICF.cpp
+++ lld/ELF/ICF.cpp
@@ -436,7 +436,7 @@
   // Initially, we use hash values to partition sections.
   parallelForEach(Sections, [&](InputSection *S) {
     // Set MSB to 1 to avoid collisions with non-hash IDs.
-    S->Class[0] = xxHash64(toStringRef(S->Data)) | (1U << 31);
+    S->Class[0] = xxHash64(S->Data) | (1U << 31);
   });
 
   // From now on, sections in Sections vector are ordered so that sections
Index: lld/COFF/ICF.cpp
===================================================================
--- lld/COFF/ICF.cpp
+++ lld/COFF/ICF.cpp
@@ -27,6 +27,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/Parallel.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/xxhash.h"
 #include <algorithm>
 #include <atomic>
 #include <vector>
@@ -65,13 +66,6 @@
   std::atomic<bool> Repeat = {false};
 };
 
-// Returns a hash value for S.
-uint32_t ICF::getHash(SectionChunk *C) {
-  return hash_combine(C->getOutputCharacteristics(), C->SectionName,
-                      C->Relocs.size(), uint32_t(C->Header->SizeOfRawData),
-                      C->Checksum, C->getContents());
-}
-
 // Returns true if section S is subject of ICF.
 //
 // Microsoft's documentation
@@ -265,7 +259,7 @@
   // Initially, we use hash values to partition sections.
   for_each(parallel::par, Chunks.begin(), Chunks.end(), [&](SectionChunk *SC) {
     // Set MSB to 1 to avoid collisions with non-hash classs.
-    SC->Class[0] = getHash(SC) | (1 << 31);
+    SC->Class[0] = xxHash64(SC->getContents()) | (1 << 31);
   });
 
   // From now on, sections in Chunks are ordered so that sections in


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