commit 760c5a8f45cc265950990a58dc27de901dc86155
author Diego Novillo <dnovillo@google.com> Tue Oct 13 22:48:46 2015 +0000
committer Diego Novillo <dnovillo@google.com> Tue Oct 13 22:48:46 2015 +0000
tree 31d1556b19606a3e9aa555eb96d2cc5dc5382787
parent 973e0506398fa04476b0d5dfd0336beb156502c9

Sample profiles - Add a name table to the binary encoding.

Binary encoded profiles used to encode all function names inline at
every reference.  This is clearly suboptimal in terms of space.  This
patch fixes this by adding a name table to the header of the file.

llvm-svn: 250241

llvm/lib/ProfileData/SampleProfReader.cpp

diff --git a/llvm/lib/ProfileData/SampleProfReader.cpp b/llvm/lib/ProfileData/SampleProfReader.cpp
index c620d4c..a058274 100644
--- a/llvm/lib/ProfileData/SampleProfReader.cpp
+++ b/llvm/lib/ProfileData/SampleProfReader.cpp
@@ -378,6 +378,16 @@
   return Str;
 }
 
+ErrorOr<StringRef> SampleProfileReaderBinary::readStringFromTable() {
+  std::error_code EC;
+  auto Idx = readNumber<unsigned>();
+  if (std::error_code EC = Idx.getError())
+    return EC;
+  if (*Idx >= NameTable.size())
+    return sampleprof_error::truncated_name_table;
+  return NameTable[*Idx];
+}
+
 std::error_code
 SampleProfileReaderBinary::readProfile(FunctionSamples &FProfile) {
   auto Val = readNumber<unsigned>();
@@ -413,7 +423,7 @@
       return EC;
 
     for (unsigned J = 0; J < *NumCalls; ++J) {
-      auto CalledFunction(readString());
+      auto CalledFunction(readStringFromTable());
       if (std::error_code EC = CalledFunction.getError())
         return EC;
 
@@ -442,7 +452,7 @@
     if (std::error_code EC = Discriminator.getError())
       return EC;
 
-    auto FName(readString());
+    auto FName(readStringFromTable());
     if (std::error_code EC = FName.getError())
       return EC;
 
@@ -457,7 +467,7 @@
 
 std::error_code SampleProfileReaderBinary::read() {
   while (!at_eof()) {
-    auto FName(readString());
+    auto FName(readStringFromTable());
     if (std::error_code EC = FName.getError())
       return EC;
 
@@ -489,6 +499,18 @@
   else if (*Version != SPVersion())
     return sampleprof_error::unsupported_version;
 
+  // Read the name table.
+  auto Size = readNumber<size_t>();
+  if (std::error_code EC = Size.getError())
+    return EC;
+  NameTable.reserve(*Size);
+  for (size_t I = 0; I < *Size; ++I) {
+    auto Name(readString());
+    if (std::error_code EC = Name.getError())
+      return EC;
+    NameTable.push_back(*Name);
+  }
+
   return sampleprof_error::success;
 }