[JITLoaderGDB] Read jit entry struct manually.

Summary:
Though r264012 was fancy enough to make reading the jit entry struct
work with templates, the packing and alignment attributes do not work on
Windows. So, this change makes it plain and simple with manual reading
of the jit entry struct.

Reviewers: clayborg

Subscribers: lldb-commits

Differential Revision: http://reviews.llvm.org/D18379

llvm-svn: 264217

lldb/source/Plugins/JITLoader/GDB/JITLoaderGDB.cpp

@@ -9,7 +9,10 @@
 
 // C Includes
 
+#include "llvm/Support/MathExtras.h"
+
 #include "lldb/Breakpoint/Breakpoint.h"
+#include "lldb/Core/DataBufferHeap.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Log.h"
 #include "lldb/Core/Module.h"
@@ -22,12 +25,41 @@
 #include "lldb/Target/Process.h"
 #include "lldb/Target/SectionLoadList.h"
 #include "lldb/Target/Target.h"
+#include "lldb/Utility/LLDBAssert.h"
 
 #include "JITLoaderGDB.h"
 
 using namespace lldb;
 using namespace lldb_private;
 
+//------------------------------------------------------------------
+// Debug Interface Structures
+//------------------------------------------------------------------
+typedef enum
+{
+    JIT_NOACTION = 0,
+    JIT_REGISTER_FN,
+    JIT_UNREGISTER_FN
+} jit_actions_t;
+
+template <typename ptr_t>
+struct jit_code_entry
+{
+    ptr_t    next_entry; // pointer
+    ptr_t    prev_entry; // pointer
+    ptr_t    symfile_addr; // pointer
+    uint64_t symfile_size;
+};
+
+template <typename ptr_t>
+struct jit_descriptor
+{
+    uint32_t version;
+    uint32_t action_flag; // Values are jit_action_t
+    ptr_t    relevant_entry; // pointer
+    ptr_t    first_entry; // pointer
+};
+
 namespace {
 
     PropertyDefinition
@@ -78,44 +110,34 @@ namespace {
         return g_settings_sp;
     }
 
-}  // anonymous namespace end
+    template <typename ptr_t>
+    bool ReadJITEntry(const addr_t from_addr, Process *process, jit_code_entry<ptr_t> *entry)
+    {
+        lldbassert(from_addr % sizeof(ptr_t) == 0);
 
-//------------------------------------------------------------------
-// Debug Interface Structures
-//------------------------------------------------------------------
-typedef enum
-{
-    JIT_NOACTION = 0,
-    JIT_REGISTER_FN,
-    JIT_UNREGISTER_FN
-} jit_actions_t;
+        ArchSpec::Core core = process->GetTarget().GetArchitecture().GetCore();
+        bool i386_target = ArchSpec::kCore_x86_32_first <= core && core <= ArchSpec::kCore_x86_32_last;
+        uint8_t uint64_align_bytes =  i386_target ? 4 : 8;
+        const size_t data_byte_size = llvm::alignTo(sizeof(ptr_t) * 3, uint64_align_bytes) + sizeof(uint64_t);
 
-template <typename ptr_t, bool packed_size>
-struct jit_code_entry
-{
-    ptr_t    next_entry; // pointer
-    ptr_t    prev_entry; // pointer
-    ptr_t    symfile_addr; // pointer
-    uint64_t symfile_size __attribute__ ((aligned (8)));
-};
+        Error error;
+        DataBufferHeap data(data_byte_size, 0);
+        size_t bytes_read = process->ReadMemory(from_addr, data.GetBytes(), data.GetByteSize(), error);
+        if (bytes_read != data_byte_size || !error.Success())
+            return false;
 
-template <typename ptr_t>
-struct jit_code_entry<ptr_t, true>
-{
-    ptr_t    next_entry; // pointer
-    ptr_t    prev_entry; // pointer
-    ptr_t    symfile_addr; // pointer
-    uint64_t symfile_size __attribute__ ((packed));
-};
+        DataExtractor extractor (data.GetBytes(), data.GetByteSize(), process->GetByteOrder(), sizeof(ptr_t));
+        lldb::offset_t offset = 0;
+        entry->next_entry = extractor.GetPointer(&offset);
+        entry->prev_entry = extractor.GetPointer(&offset);
+        entry->symfile_addr = extractor.GetPointer(&offset);
+        offset = llvm::alignTo(offset, uint64_align_bytes);
+        entry->symfile_size = extractor.GetU64(&offset);
 
-template <typename ptr_t>
-struct jit_descriptor
-{
-    uint32_t version;
-    uint32_t action_flag; // Values are jit_action_t
-    ptr_t    relevant_entry; // pointer
-    ptr_t    first_entry; // pointer
-};
+        return true;
+    }
+
+}  // anonymous namespace end
 
 JITLoaderGDB::JITLoaderGDB (lldb_private::Process *process) :
     JITLoader(process),
@@ -278,21 +300,13 @@ static void updateSectionLoadAddress(const SectionList &section_list,
 bool
 JITLoaderGDB::ReadJITDescriptor(bool all_entries)
 {
-    Target &target = m_process->GetTarget();
-    const ArchSpec &arch_spec = target.GetArchitecture();
-    if (arch_spec.GetAddressByteSize() == 8)
-        return ReadJITDescriptorImpl<uint64_t, false>(all_entries);
+    if (m_process->GetTarget().GetArchitecture().GetAddressByteSize() == 8)
+        return ReadJITDescriptorImpl<uint64_t>(all_entries);
     else
-    {
-        ArchSpec::Core core = arch_spec.GetCore();
-        if (ArchSpec::kCore_x86_32_first <= core && core <= ArchSpec::kCore_x86_32_last)
-            return ReadJITDescriptorImpl<uint32_t, true>(all_entries);
-        else
-            return ReadJITDescriptorImpl<uint32_t, false>(all_entries);
-    }
+        return ReadJITDescriptorImpl<uint32_t>(all_entries);
 }
 
-template <typename ptr_t, bool packed>
+template <typename ptr_t>
 bool
 JITLoaderGDB::ReadJITDescriptorImpl(bool all_entries)
 {
@@ -326,10 +340,8 @@ JITLoaderGDB::ReadJITDescriptorImpl(bool all_entries)
 
     while (jit_relevant_entry != 0)
     {
-        jit_code_entry<ptr_t, packed> jit_entry;
-        const size_t jit_entry_size = sizeof(jit_entry);
-        bytes_read = m_process->DoReadMemory(jit_relevant_entry, &jit_entry, jit_entry_size, error);
-        if (bytes_read != jit_entry_size || !error.Success())
+        jit_code_entry<ptr_t> jit_entry;
+        if (!ReadJITEntry(jit_relevant_entry, m_process, &jit_entry))
         {
             if (log)
                 log->Printf(

lldb/source/Plugins/JITLoader/GDB/JITLoaderGDB.h

@@ -83,7 +83,7 @@ class JITLoaderGDB : public lldb_private::JITLoader
     bool
     ReadJITDescriptor(bool all_entries);
 
-    template <typename ptr_t, bool packed>
+    template <typename ptr_t>
     bool
     ReadJITDescriptorImpl(bool all_entries);