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llvm-mirror/unittests/Support/DataExtractorTest.cpp
Pavel Labath d0775d3cfb Add error handling to the DataExtractor class
Summary:
This is motivated by D63591, where we realized that there isn't a really
good way of telling whether a DataExtractor is reading actual data, or
is it just returning default values because it reached the end of the
buffer.

This patch resolves that by providing a new "Cursor" class. A Cursor
object encapsulates two things:
- the current position/offset in the DataExtractor
- an error object

Storing the error object inside the Cursor enables one to use the same
pattern as the std::{io}stream API, where one can blindly perform a
sequence of reads and only check for errors once at the end of the
operation. Similarly to the stream API, as soon as we encounter one
error, all of the subsequent operations are skipped (return default
values) too, even if the would suceed with clear error state. Unlike the
std::stream API (but in line with other llvm APIs), we force the error
state to be checked through usage of llvm::Error.

Reviewers: probinson, dblaikie, JDevlieghere, aprantl, echristo

Subscribers: kristina, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63713

llvm-svn: 370042
2019-08-27 11:24:08 +00:00

273 lines
7.9 KiB
C++

//===- llvm/unittest/Support/DataExtractorTest.cpp - DataExtractor tests --===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/DataExtractor.h"
#include "llvm/Testing/Support/Error.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
const char numberData[] = "\x80\x90\xFF\xFF\x80\x00\x00\x00";
const char stringData[] = "hellohello\0hello";
const char leb128data[] = "\xA6\x49";
const char bigleb128data[] = "\xAA\xA9\xFF\xAA\xFF\xAA\xFF\x4A";
TEST(DataExtractorTest, OffsetOverflow) {
DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
EXPECT_FALSE(DE.isValidOffsetForDataOfSize(-2U, 5));
}
TEST(DataExtractorTest, UnsignedNumbers) {
DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
uint64_t offset = 0;
EXPECT_EQ(0x80U, DE.getU8(&offset));
EXPECT_EQ(1U, offset);
offset = 0;
EXPECT_EQ(0x8090U, DE.getU16(&offset));
EXPECT_EQ(2U, offset);
offset = 0;
EXPECT_EQ(0x8090FFFFU, DE.getU32(&offset));
EXPECT_EQ(4U, offset);
offset = 0;
EXPECT_EQ(0x8090FFFF80000000ULL, DE.getU64(&offset));
EXPECT_EQ(8U, offset);
offset = 0;
EXPECT_EQ(0x8090FFFF80000000ULL, DE.getAddress(&offset));
EXPECT_EQ(8U, offset);
offset = 0;
uint32_t data[2];
EXPECT_EQ(data, DE.getU32(&offset, data, 2));
EXPECT_EQ(0x8090FFFFU, data[0]);
EXPECT_EQ(0x80000000U, data[1]);
EXPECT_EQ(8U, offset);
offset = 0;
// Now for little endian.
DE = DataExtractor(StringRef(numberData, sizeof(numberData)-1), true, 4);
EXPECT_EQ(0x9080U, DE.getU16(&offset));
EXPECT_EQ(2U, offset);
offset = 0;
EXPECT_EQ(0xFFFF9080U, DE.getU32(&offset));
EXPECT_EQ(4U, offset);
offset = 0;
EXPECT_EQ(0x80FFFF9080ULL, DE.getU64(&offset));
EXPECT_EQ(8U, offset);
offset = 0;
EXPECT_EQ(0xFFFF9080U, DE.getAddress(&offset));
EXPECT_EQ(4U, offset);
offset = 0;
EXPECT_EQ(data, DE.getU32(&offset, data, 2));
EXPECT_EQ(0xFFFF9080U, data[0]);
EXPECT_EQ(0x80U, data[1]);
EXPECT_EQ(8U, offset);
}
TEST(DataExtractorTest, SignedNumbers) {
DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
uint64_t offset = 0;
EXPECT_EQ(-128, DE.getSigned(&offset, 1));
EXPECT_EQ(1U, offset);
offset = 0;
EXPECT_EQ(-32624, DE.getSigned(&offset, 2));
EXPECT_EQ(2U, offset);
offset = 0;
EXPECT_EQ(-2137980929, DE.getSigned(&offset, 4));
EXPECT_EQ(4U, offset);
offset = 0;
EXPECT_EQ(-9182558167379214336LL, DE.getSigned(&offset, 8));
EXPECT_EQ(8U, offset);
}
TEST(DataExtractorTest, Strings) {
DataExtractor DE(StringRef(stringData, sizeof(stringData)-1), false, 8);
uint64_t offset = 0;
EXPECT_EQ(stringData, DE.getCStr(&offset));
EXPECT_EQ(11U, offset);
EXPECT_EQ(nullptr, DE.getCStr(&offset));
EXPECT_EQ(11U, offset);
}
TEST(DataExtractorTest, LEB128) {
DataExtractor DE(StringRef(leb128data, sizeof(leb128data)-1), false, 8);
uint64_t offset = 0;
EXPECT_EQ(9382ULL, DE.getULEB128(&offset));
EXPECT_EQ(2U, offset);
offset = 0;
EXPECT_EQ(-7002LL, DE.getSLEB128(&offset));
EXPECT_EQ(2U, offset);
DataExtractor BDE(StringRef(bigleb128data, sizeof(bigleb128data)-1), false,8);
offset = 0;
EXPECT_EQ(42218325750568106ULL, BDE.getULEB128(&offset));
EXPECT_EQ(8U, offset);
offset = 0;
EXPECT_EQ(-29839268287359830LL, BDE.getSLEB128(&offset));
EXPECT_EQ(8U, offset);
}
TEST(DataExtractorTest, LEB128_error) {
DataExtractor DE(StringRef("\x81"), false, 8);
uint64_t Offset = 0;
EXPECT_EQ(0U, DE.getULEB128(&Offset));
EXPECT_EQ(0U, Offset);
Offset = 0;
EXPECT_EQ(0U, DE.getSLEB128(&Offset));
EXPECT_EQ(0U, Offset);
}
TEST(DataExtractorTest, Cursor_tell) {
DataExtractor DE(StringRef("AB"), false, 8);
DataExtractor::Cursor C(0);
// A successful read operation advances the cursor
EXPECT_EQ('A', DE.getU8(C));
EXPECT_EQ(1u, C.tell());
// An unsuccessful one doesn't.
EXPECT_EQ(0u, DE.getU16(C));
EXPECT_EQ(1u, C.tell());
// And neither do any subsequent operations.
EXPECT_EQ(0, DE.getU8(C));
EXPECT_EQ(1u, C.tell());
consumeError(C.takeError());
}
TEST(DataExtractorTest, Cursor_takeError) {
DataExtractor DE(StringRef("AB"), false, 8);
DataExtractor::Cursor C(0);
// Initially, the cursor is in the "success" state.
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
// It remains "success" after a successful read.
EXPECT_EQ('A', DE.getU8(C));
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
// An unsuccessful read sets the error state.
EXPECT_EQ(0u, DE.getU32(C));
EXPECT_THAT_ERROR(C.takeError(), Failed());
// Once set the error sticks until explicitly cleared.
EXPECT_EQ(0u, DE.getU32(C));
EXPECT_EQ(0, DE.getU8(C));
EXPECT_THAT_ERROR(C.takeError(), Failed());
// At which point reads can be succeed again.
EXPECT_EQ('B', DE.getU8(C));
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
}
TEST(DataExtractorTest, Cursor_chaining) {
DataExtractor DE(StringRef("ABCD"), false, 8);
DataExtractor::Cursor C(0);
// Multiple reads can be chained without trigerring any assertions.
EXPECT_EQ('A', DE.getU8(C));
EXPECT_EQ('B', DE.getU8(C));
EXPECT_EQ('C', DE.getU8(C));
EXPECT_EQ('D', DE.getU8(C));
// And the error checked at the end.
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
}
#if defined(GTEST_HAS_DEATH_TEST) && defined(_DEBUG)
TEST(DataExtractorDeathTest, Cursor) {
DataExtractor DE(StringRef("AB"), false, 8);
// Even an unused cursor must be checked for errors:
EXPECT_DEATH(DataExtractor::Cursor(0),
"Success values must still be checked prior to being destroyed");
{
auto C = std::make_unique<DataExtractor::Cursor>(0);
EXPECT_EQ(0u, DE.getU32(*C));
// It must also be checked after an unsuccessful operation.
// destruction.
EXPECT_DEATH(C.reset(), "unexpected end of data");
EXPECT_THAT_ERROR(C->takeError(), Failed());
}
{
auto C = std::make_unique<DataExtractor::Cursor>(0);
EXPECT_EQ('A', DE.getU8(*C));
// Same goes for a successful one.
EXPECT_DEATH(
C.reset(),
"Success values must still be checked prior to being destroyed");
EXPECT_THAT_ERROR(C->takeError(), Succeeded());
}
{
auto C = std::make_unique<DataExtractor::Cursor>(0);
EXPECT_EQ('A', DE.getU8(*C));
EXPECT_EQ(0u, DE.getU32(*C));
// Even if a successful operation is followed by an unsuccessful one.
EXPECT_DEATH(C.reset(), "unexpected end of data");
EXPECT_THAT_ERROR(C->takeError(), Failed());
}
{
auto C = std::make_unique<DataExtractor::Cursor>(0);
EXPECT_EQ(0u, DE.getU32(*C));
EXPECT_EQ(0, DE.getU8(*C));
// Even if an unsuccessful operation is followed by one that would normally
// succeed.
EXPECT_DEATH(C.reset(), "unexpected end of data");
EXPECT_THAT_ERROR(C->takeError(), Failed());
}
}
#endif
TEST(DataExtractorTest, getU8_vector) {
DataExtractor DE(StringRef("AB"), false, 8);
DataExtractor::Cursor C(0);
SmallVector<uint8_t, 2> S;
DE.getU8(C, S, 4);
EXPECT_THAT_ERROR(C.takeError(), Failed());
EXPECT_EQ("", toStringRef(S));
DE.getU8(C, S, 2);
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
EXPECT_EQ("AB", toStringRef(S));
}
TEST(DataExtractorTest, skip) {
DataExtractor DE(StringRef("AB"), false, 8);
DataExtractor::Cursor C(0);
DE.skip(C, 4);
EXPECT_THAT_ERROR(C.takeError(), Failed());
EXPECT_EQ(0u, C.tell());
DE.skip(C, 2);
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
EXPECT_EQ(2u, C.tell());
}
TEST(DataExtractorTest, eof) {
DataExtractor DE(StringRef("A"), false, 8);
DataExtractor::Cursor C(0);
EXPECT_FALSE(DE.eof(C));
EXPECT_EQ(0, DE.getU16(C));
EXPECT_FALSE(DE.eof(C));
EXPECT_THAT_ERROR(C.takeError(), Failed());
EXPECT_EQ('A', DE.getU8(C));
EXPECT_TRUE(DE.eof(C));
EXPECT_THAT_ERROR(C.takeError(), Succeeded());
}
}