[Support] Add MemoryBuffer::getFileSlice()
mach-o supports "fat" files which are a header/table-of-contents followed by a
concatenation of mach-o files built for different architectures. Currently,
MemoryBuffer has no easy way to map a subrange (slice) of a file which lld
will need to select a mach-o slice of a fat file. The new function provides
an easy way to map a slice of a file into a MemoryBuffer. Test case included.
llvm-svn: 219260
diff --git a/llvm/unittests/Support/MemoryBufferTest.cpp b/llvm/unittests/Support/MemoryBufferTest.cpp
index 93bf301..1cdd6ad 100644
--- a/llvm/unittests/Support/MemoryBufferTest.cpp
+++ b/llvm/unittests/Support/MemoryBufferTest.cpp
@@ -169,4 +169,54 @@
testGetOpenFileSlice(true);
}
+
+TEST_F(MemoryBufferTest, slice) {
+ // Create a file that is six pages long with different data on each page.
+ int FD;
+ SmallString<64> TestPath;
+ sys::fs::createTemporaryFile("MemoryBufferTest_Slice", "temp", FD, TestPath);
+ raw_fd_ostream OF(FD, true, /*unbuffered=*/true);
+ for (unsigned i = 0; i < 0x2000 / 8; ++i) {
+ OF << "12345678";
+ }
+ for (unsigned i = 0; i < 0x2000 / 8; ++i) {
+ OF << "abcdefgh";
+ }
+ for (unsigned i = 0; i < 0x2000 / 8; ++i) {
+ OF << "ABCDEFGH";
+ }
+ OF.close();
+
+ // Try offset of one page.
+ ErrorOr<OwningBuffer> MB = MemoryBuffer::getFileSlice(TestPath.str(),
+ 0x4000, 0x1000);
+ std::error_code EC = MB.getError();
+ ASSERT_FALSE(EC);
+ EXPECT_EQ(0x4000UL, MB.get()->getBufferSize());
+
+ StringRef BufData = MB.get()->getBuffer();
+ EXPECT_TRUE(BufData.substr(0x0000,8).equals("12345678"));
+ EXPECT_TRUE(BufData.substr(0x0FF8,8).equals("12345678"));
+ EXPECT_TRUE(BufData.substr(0x1000,8).equals("abcdefgh"));
+ EXPECT_TRUE(BufData.substr(0x2FF8,8).equals("abcdefgh"));
+ EXPECT_TRUE(BufData.substr(0x3000,8).equals("ABCDEFGH"));
+ EXPECT_TRUE(BufData.substr(0x3FF8,8).equals("ABCDEFGH"));
+
+ // Try non-page aligned.
+ ErrorOr<OwningBuffer> MB2 = MemoryBuffer::getFileSlice(TestPath.str(),
+ 0x3000, 0x0800);
+ EC = MB2.getError();
+ ASSERT_FALSE(EC);
+ EXPECT_EQ(0x3000UL, MB2.get()->getBufferSize());
+
+ StringRef BufData2 = MB2.get()->getBuffer();
+ EXPECT_TRUE(BufData2.substr(0x0000,8).equals("12345678"));
+ EXPECT_TRUE(BufData2.substr(0x17F8,8).equals("12345678"));
+ EXPECT_TRUE(BufData2.substr(0x1800,8).equals("abcdefgh"));
+ EXPECT_TRUE(BufData2.substr(0x2FF8,8).equals("abcdefgh"));
+
+}
+
+
+
}