[LLDB] Let DataExtractor deal with two-byte addresses

AVR usually uses two byte addresses. By making DataExtractor deal with
this, it is possible to load AVR binaries that don't have debug info
associated with them.

Differential Revision: https://reviews.llvm.org/D73969

Author: aykevl

lldb/source/Utility/DataExtractor.cpp

@@ -133,7 +133,7 @@ DataExtractor::DataExtractor(const void *data, offset_t length,
       m_end(const_cast<uint8_t *>(static_cast<const uint8_t *>(data)) + length),
       m_byte_order(endian), m_addr_size(addr_size), m_data_sp(),
       m_target_byte_size(target_byte_size) {
-  assert(addr_size == 4 || addr_size == 8);
+  assert(addr_size >= 1 && addr_size <= 8);
 }
 
 // Make a shared pointer reference to the shared data in "data_sp" and set the
@@ -146,7 +146,7 @@ DataExtractor::DataExtractor(const DataBufferSP &data_sp, ByteOrder endian,
     : m_start(nullptr), m_end(nullptr), m_byte_order(endian),
       m_addr_size(addr_size), m_data_sp(),
       m_target_byte_size(target_byte_size) {
-  assert(addr_size == 4 || addr_size == 8);
+  assert(addr_size >= 1 && addr_size <= 8);
   SetData(data_sp);
 }
 
@@ -160,7 +160,7 @@ DataExtractor::DataExtractor(const DataExtractor &data, offset_t offset,
     : m_start(nullptr), m_end(nullptr), m_byte_order(data.m_byte_order),
       m_addr_size(data.m_addr_size), m_data_sp(),
       m_target_byte_size(target_byte_size) {
-  assert(m_addr_size == 4 || m_addr_size == 8);
+  assert(m_addr_size >= 1 && m_addr_size <= 8);
   if (data.ValidOffset(offset)) {
     offset_t bytes_available = data.GetByteSize() - offset;
     if (length > bytes_available)
@@ -173,7 +173,7 @@ DataExtractor::DataExtractor(const DataExtractor &rhs)
     : m_start(rhs.m_start), m_end(rhs.m_end), m_byte_order(rhs.m_byte_order),
       m_addr_size(rhs.m_addr_size), m_data_sp(rhs.m_data_sp),
       m_target_byte_size(rhs.m_target_byte_size) {
-  assert(m_addr_size == 4 || m_addr_size == 8);
+  assert(m_addr_size >= 1 && m_addr_size <= 8);
 }
 
 // Assignment operator
@@ -251,7 +251,7 @@ lldb::offset_t DataExtractor::SetData(const DataExtractor &data,
                                       offset_t data_offset,
                                       offset_t data_length) {
   m_addr_size = data.m_addr_size;
-  assert(m_addr_size == 4 || m_addr_size == 8);
+  assert(m_addr_size >= 1 && m_addr_size <= 8);
   // If "data" contains shared pointer to data, then we can use that
   if (data.m_data_sp) {
     m_byte_order = data.m_byte_order;
@@ -680,12 +680,12 @@ long double DataExtractor::GetLongDouble(offset_t *offset_ptr) const {
 //
 // RETURNS the address that was extracted, or zero on failure.
 uint64_t DataExtractor::GetAddress(offset_t *offset_ptr) const {
-  assert(m_addr_size == 4 || m_addr_size == 8);
+  assert(m_addr_size >= 1 && m_addr_size <= 8);
   return GetMaxU64(offset_ptr, m_addr_size);
 }
 
 uint64_t DataExtractor::GetAddress_unchecked(offset_t *offset_ptr) const {
-  assert(m_addr_size == 4 || m_addr_size == 8);
+  assert(m_addr_size >= 1 && m_addr_size <= 8);
   return GetMaxU64_unchecked(offset_ptr, m_addr_size);
 }
 

lldb/unittests/Utility/DataExtractorTest.cpp

@@ -112,6 +112,39 @@ TEST(DataExtractorTest, GetCStrAtNullOffset) {
   EXPECT_EQ(4U, offset);
 }
 
+TEST(DataExtractorTest, UncommonAddressSize) {
+  uint8_t buffer[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
+  DataExtractor E2(buffer, sizeof buffer, lldb::eByteOrderLittle, 2);
+  DataExtractor E5(buffer, sizeof buffer, lldb::eByteOrderLittle, 5);
+  DataExtractor E7(buffer, sizeof buffer, lldb::eByteOrderLittle, 7);
+
+  lldb::offset_t offset;
+
+  // Test 2-byte addresses (for AVR).
+  offset = 0;
+  EXPECT_EQ(0x0201U, E2.GetMaxU64(&offset, 2));
+  EXPECT_EQ(2U, offset);
+  offset = 0;
+  EXPECT_EQ(0x0201U, E2.GetAddress(&offset));
+  EXPECT_EQ(2U, offset);
+
+  // Test 5-byte addresses.
+  offset = 0;
+  EXPECT_EQ(0x030201U, E5.GetMaxU64(&offset, 3));
+  EXPECT_EQ(3U, offset);
+  offset = 3;
+  EXPECT_EQ(0x0807060504U, E5.GetAddress(&offset));
+  EXPECT_EQ(8U, offset);
+
+  // Test 7-byte addresses.
+  offset = 0;
+  EXPECT_EQ(0x0504030201U, E7.GetMaxU64(&offset, 5));
+  EXPECT_EQ(5U, offset);
+  offset = 0;
+  EXPECT_EQ(0x07060504030201U, E7.GetAddress(&offset));
+  EXPECT_EQ(7U, offset);
+}
+
 TEST(DataExtractorTest, GetMaxU64) {
   uint8_t buffer[] = {0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08};
   DataExtractor LE(buffer, sizeof(buffer), lldb::eByteOrderLittle,