[PATCH] D124746: Make BinaryStreamWriter::padToAlignment write blocks vs bytes.

[Stella Laurenzo via Phabricator via llvm-commits]

stellaraccident updated this revision to Diff 426322.
stellaraccident added a comment.

Add unit test.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D124746/new/

https://reviews.llvm.org/D124746

Files:
  llvm/lib/Support/BinaryStreamWriter.cpp
  llvm/unittests/Support/BinaryStreamTest.cpp


Index: llvm/unittests/Support/BinaryStreamTest.cpp
===================================================================
--- llvm/unittests/Support/BinaryStreamTest.cpp
+++ llvm/unittests/Support/BinaryStreamTest.cpp
@@ -807,7 +807,7 @@
   }
 }
 
-TEST_F(BinaryStreamTest, StringWriterStrings) {
+TEST_F(BinaryStreamTest, StreamWriterStrings) {
   StringRef Strings[] = {"First", "Second", "Third", "Fourth"};
 
   size_t Length = 0;
@@ -831,6 +831,47 @@
   }
 }
 
+TEST_F(BinaryStreamTest, StreamWriterPadToAlignment) {
+  // This test may seem excessive but it is checking for past bugs and corner
+  // cases by making sure that the stream is allowed to grow and that
+  // both multiple pad chunks and single chunk extensions work.
+  AppendingBinaryByteStream Stream(support::little);
+  BinaryStreamWriter Writer(Stream);
+
+  // Offset 0: '0'
+  EXPECT_THAT_ERROR(Writer.writeInteger('0'), Succeeded());
+  // Offset 1..110: 0
+  EXPECT_THAT_ERROR(Writer.padToAlignment(111), Succeeded());
+  // Offset 111: '*'
+  EXPECT_THAT_ERROR(Writer.writeInteger('*'), Succeeded());
+  // Offset 112..120: 0
+  EXPECT_THAT_ERROR(Writer.padToAlignment(11), Succeeded());
+
+  BinaryStreamReader Reader(Stream);
+  char c;
+  // Offset 0
+  EXPECT_THAT_ERROR(Reader.readInteger<char>(c), Succeeded());
+  EXPECT_EQ('0', c);
+  // Offset 1..110
+  for (int i = 0; i < 110; ++i) {
+    char c;
+    EXPECT_THAT_ERROR(Reader.readInteger<char>(c), Succeeded());
+    EXPECT_EQ('\0', c);
+  }
+  // Offset 111
+  EXPECT_THAT_ERROR(Reader.readInteger<char>(c), Succeeded());
+  EXPECT_EQ('*', c);
+  // Offset 112..120
+  for (int i = 0; i < 9; ++i) {
+    char c;
+    EXPECT_THAT_ERROR(Reader.readInteger<char>(c), Succeeded());
+    EXPECT_EQ('\0', c);
+  }
+
+  // EOF.
+  EXPECT_THAT_ERROR(Reader.readInteger<char>(c), Failed());
+}
+
 TEST_F(BinaryStreamTest, StreamWriterAppend) {
   StringRef Strings[] = {"First", "Second", "Third", "Fourth"};
   AppendingBinaryByteStream Stream(support::little);
Index: llvm/lib/Support/BinaryStreamWriter.cpp
===================================================================
--- llvm/lib/Support/BinaryStreamWriter.cpp
+++ llvm/lib/Support/BinaryStreamWriter.cpp
@@ -13,6 +13,8 @@
 #include "llvm/Support/BinaryStreamRef.h"
 #include "llvm/Support/LEB128.h"
 
+#include <cstring>
+
 using namespace llvm;
 
 BinaryStreamWriter::BinaryStreamWriter(WritableBinaryStreamRef Ref)
@@ -94,10 +96,12 @@
 
 Error BinaryStreamWriter::padToAlignment(uint32_t Align) {
   uint64_t NewOffset = alignTo(Offset, Align);
-  if (NewOffset > getLength())
-    return make_error<BinaryStreamError>(stream_error_code::stream_too_short);
+  const uint64_t ZerosSize = 64;
+  char Zeros[ZerosSize];
+  std::memset(Zeros, 0, ZerosSize);
   while (Offset < NewOffset)
-    if (auto EC = writeInteger('\0'))
-      return EC;
+    if (auto E = writeArray(
+            ArrayRef<char>(Zeros, std::min(ZerosSize, NewOffset - Offset))))
+      return E;
   return Error::success();
 }


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