Remove FileSpec::ReadFileContents.

This functionality is subsumed by DataBufferLLVM, which is
also more efficient since it will try to mmap.  However, we
don't yet support mmaping writable private sections, and in
some cases we were using ReadFileContents and then modifying
the buffer.  To address that I've added a flag to the
DataBufferLLVM methods that allow you to map privately, which
disables the mmaping path entirely.  Eventually we should teach
DataBufferLLVM to use mmap with writable private, but that is
orthogonal to this effort.

Differential Revision: https://reviews.llvm.org/D30622

llvm-svn: 297095

3 files changed, 23 insertions, 19 deletions

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index 8a4734bd337..10213f572b8 100644
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -388,7 +388,7 @@ ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
                                           lldb::offset_t length) {
   if (!data_sp) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
     data_offset = 0;
@@ -406,7 +406,7 @@ ObjectFile *ObjectFileELF::CreateInstance(const lldb::ModuleSP &module_sp,
   // Update the data to contain the entire file if it doesn't already
   if (data_sp->GetByteSize() < length) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
     data_offset = 0;
@@ -665,7 +665,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
           size_t section_header_end = header.e_shoff + header.e_shentsize;
           if (header.HasHeaderExtension() &&
             section_header_end > data_sp->GetByteSize()) {
-            data_sp = DataBufferLLVM::CreateFromPath(
+            data_sp = DataBufferLLVM::CreateSliceFromPath(
                 file.GetPath(), section_header_end, file_offset);
             if (data_sp) {
               data.SetData(data_sp);
@@ -679,7 +679,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
           section_header_end =
               header.e_shoff + header.e_shnum * header.e_shentsize;
           if (section_header_end > data_sp->GetByteSize()) {
-            data_sp = DataBufferLLVM::CreateFromPath(
+            data_sp = DataBufferLLVM::CreateSliceFromPath(
                 file.GetPath(), section_header_end, file_offset);
             if (data_sp)
               data.SetData(data_sp);
@@ -724,7 +724,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
                 size_t program_headers_end =
                     header.e_phoff + header.e_phnum * header.e_phentsize;
                 if (program_headers_end > data_sp->GetByteSize()) {
-                  data_sp = DataBufferLLVM::CreateFromPath(
+                  data_sp = DataBufferLLVM::CreateSliceFromPath(
                       file.GetPath(), program_headers_end, file_offset);
                   if (data_sp)
                     data.SetData(data_sp);
@@ -740,7 +740,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
                 }
 
                 if (segment_data_end > data_sp->GetByteSize()) {
-                  data_sp = DataBufferLLVM::CreateFromPath(
+                  data_sp = DataBufferLLVM::CreateSliceFromPath(
                       file.GetPath(), segment_data_end, file_offset);
                   if (data_sp)
                     data.SetData(data_sp);
@@ -750,7 +750,7 @@ size_t ObjectFileELF::GetModuleSpecifications(
                     CalculateELFNotesSegmentsCRC32(program_headers, data);
               } else {
                 // Need to map entire file into memory to calculate the crc.
-                data_sp = DataBufferLLVM::CreateFromPath(file.GetPath(), -1,
+                data_sp = DataBufferLLVM::CreateSliceFromPath(file.GetPath(), -1,
                                                          file_offset);
                 if (data_sp) {
                   data.SetData(data_sp);
diff --git a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
index 5901a1b4935..a6d5a85e2d4 100644
--- a/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
+++ b/lldb/source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
@@ -860,7 +860,7 @@ ObjectFile *ObjectFileMachO::CreateInstance(const lldb::ModuleSP &module_sp,
                                             lldb::offset_t length) {
   if (!data_sp) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
     data_offset = 0;
@@ -872,7 +872,7 @@ ObjectFile *ObjectFileMachO::CreateInstance(const lldb::ModuleSP &module_sp,
   // Update the data to contain the entire file if it doesn't already
   if (data_sp->GetByteSize() < length) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
     data_offset = 0;
@@ -911,7 +911,8 @@ size_t ObjectFileMachO::GetModuleSpecifications(
       size_t header_and_load_cmds =
           header.sizeofcmds + MachHeaderSizeFromMagic(header.magic);
       if (header_and_load_cmds >= data_sp->GetByteSize()) {
-        data_sp = file.ReadFileContents(file_offset, header_and_load_cmds);
+        data_sp = DataBufferLLVM::CreateSliceFromPath(
+            file.GetPath(), header_and_load_cmds, file_offset);
         data.SetData(data_sp);
         data_offset = MachHeaderSizeFromMagic(header.magic);
       }
@@ -1123,8 +1124,8 @@ bool ObjectFileMachO::ParseHeader() {
                   ReadMemory(process_sp, m_memory_addr, header_and_lc_size);
             } else {
               // Read in all only the load command data from the file on disk
-              data_sp =
-                  m_file.ReadFileContents(m_file_offset, header_and_lc_size);
+              data_sp = DataBufferLLVM::CreateSliceFromPath(
+                  m_file.GetPath(), header_and_lc_size, m_file_offset);
               if (data_sp->GetByteSize() != header_and_lc_size)
                 return false;
             }
@@ -2095,7 +2096,7 @@ UUID ObjectFileMachO::GetSharedCacheUUID(FileSpec dyld_shared_cache,
                                          const ByteOrder byte_order,
                                          const uint32_t addr_byte_size) {
   UUID dsc_uuid;
-  DataBufferSP DscData = DataBufferLLVM::CreateFromPath(
+  DataBufferSP DscData = DataBufferLLVM::CreateSliceFromPath(
       dyld_shared_cache.GetPath(),
       sizeof(struct lldb_copy_dyld_cache_header_v1), 0);
   if (!DscData)
@@ -2703,7 +2704,7 @@ size_t ObjectFileMachO::ParseSymtab() {
 
       // Process the dyld shared cache header to find the unmapped symbols
 
-      DataBufferSP dsc_data_sp = DataBufferLLVM::CreateFromPath(
+      DataBufferSP dsc_data_sp = DataBufferLLVM::CreateSliceFromPath(
           dsc_filespec.GetPath(), sizeof(struct lldb_copy_dyld_cache_header_v1),
           0);
       if (!dsc_uuid.IsValid()) {
@@ -2738,7 +2739,7 @@ size_t ObjectFileMachO::ParseSymtab() {
             mappingOffset >= sizeof(struct lldb_copy_dyld_cache_header_v1)) {
 
           DataBufferSP dsc_mapping_info_data_sp =
-              DataBufferLLVM::CreateFromPath(
+              DataBufferLLVM::CreateSliceFromPath(
                   dsc_filespec.GetPath(),
                   sizeof(struct lldb_copy_dyld_cache_mapping_info),
                   mappingOffset);
@@ -2765,7 +2766,7 @@ size_t ObjectFileMachO::ParseSymtab() {
           if (localSymbolsOffset && localSymbolsSize) {
             // Map the local symbols
             DataBufferSP dsc_local_symbols_data_sp =
-                DataBufferLLVM::CreateFromPath(dsc_filespec.GetPath(),
+                DataBufferLLVM::CreateSliceFromPath(dsc_filespec.GetPath(),
                                                localSymbolsSize,
                                                localSymbolsOffset);
 
diff --git a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
index b9577b5d1f2..df665129ae2 100644
--- a/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
+++ b/lldb/source/Plugins/ObjectFile/PECOFF/ObjectFilePECOFF.cpp
@@ -68,7 +68,7 @@ ObjectFile *ObjectFilePECOFF::CreateInstance(const lldb::ModuleSP &module_sp,
                                              lldb::offset_t length) {
   if (!data_sp) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
     data_offset = 0;
@@ -80,7 +80,7 @@ ObjectFile *ObjectFilePECOFF::CreateInstance(const lldb::ModuleSP &module_sp,
   // Update the data to contain the entire file if it doesn't already
   if (data_sp->GetByteSize() < length) {
     data_sp =
-        DataBufferLLVM::CreateFromPath(file->GetPath(), length, file_offset);
+        DataBufferLLVM::CreateSliceFromPath(file->GetPath(), length, file_offset);
     if (!data_sp)
       return nullptr;
   }
@@ -430,7 +430,10 @@ bool ObjectFilePECOFF::ParseCOFFOptionalHeader(lldb::offset_t *offset_ptr) {
 
 DataExtractor ObjectFilePECOFF::ReadImageData(uint32_t offset, size_t size) {
   if (m_file) {
-    DataBufferSP buffer_sp(m_file.ReadFileContents(offset, size));
+    // A bit of a hack, but we intend to write to this buffer, so we can't 
+    // mmap it.
+    auto buffer_sp =
+        DataBufferLLVM::CreateSliceFromPath(m_file.GetPath(), size, offset, true);
     return DataExtractor(buffer_sp, GetByteOrder(), GetAddressByteSize());
   }
   ProcessSP process_sp(m_process_wp.lock());