[Lldb-commits] [lldb] r267291 - ObjectFile: parse EABI Attributes

[Saleem Abdulrasool via lldb-commits]

Author: compnerd
Date: Sat Apr 23 11:00:15 2016
New Revision: 267291

URL: http://llvm.org/viewvc/llvm-project?rev=267291&view=rev
Log:
ObjectFile: parse EABI Attributes

This adds basic parsing of the EABI attributes section.  This section contains
additional information about the target for which the file was built.  Attempt
to infer additional architecture information from that section.

Modified:
    lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
    lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h

Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp?rev=267291&r1=267290&r2=267291&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp (original)
+++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp Sat Apr 23 11:00:15 2016
@@ -31,6 +31,7 @@
 
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/ARMBuildAttributes.h"
 #include "llvm/Support/MathExtras.h"
 
 #define CASE_AND_STREAM(s, def, width)                  \
@@ -1516,6 +1517,93 @@ ObjectFileELF::RefineModuleDetailsFromNo
     return error;
 }
 
+void
+ObjectFileELF::ParseARMAttributes(DataExtractor &data, uint64_t length, ArchSpec &arch_spec)
+{
+    lldb::offset_t Offset = 0;
+
+    uint8_t FormatVersion = data.GetU8(&Offset);
+    if (FormatVersion != llvm::ARMBuildAttrs::Format_Version)
+      return;
+
+    Offset = Offset + sizeof(uint32_t); // Section Length
+    llvm::StringRef VendorName = data.GetCStr(&Offset);
+
+    if (VendorName != "aeabi")
+      return;
+
+    if (arch_spec.GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment)
+        arch_spec.GetTriple().setEnvironment(llvm::Triple::EABI);
+
+    while (Offset < length)
+    {
+        uint8_t Tag = data.GetU8(&Offset);
+        uint32_t Size = data.GetU32(&Offset);
+
+        if (Tag != llvm::ARMBuildAttrs::File || Size == 0)
+            continue;
+
+        while (Offset < length)
+        {
+            uint64_t Tag = data.GetULEB128(&Offset);
+            switch (Tag)
+            {
+                default:
+                    if (Tag < 32)
+                        data.GetULEB128(&Offset);
+                    else if (Tag % 2 == 0)
+                        data.GetULEB128(&Offset);
+                    else
+                        data.GetCStr(&Offset);
+
+                    break;
+
+                case llvm::ARMBuildAttrs::CPU_raw_name:
+                case llvm::ARMBuildAttrs::CPU_name:
+                    data.GetCStr(&Offset);
+
+                    break;
+
+                case llvm::ARMBuildAttrs::THUMB_ISA_use:
+                {
+                    uint64_t ThumbISA = data.GetULEB128(&Offset);
+
+                    // NOTE: ignore ThumbISA == llvm::ARMBuildAttrs::AllowThumbDerived
+                    // since that derives it based on the architecutre/profile
+                    if (ThumbISA == llvm::ARMBuildAttrs::AllowThumb32)
+                        if (arch_spec.GetTriple().getArch() == llvm::Triple::UnknownArch ||
+                            arch_spec.GetTriple().getArch() == llvm::Triple::arm)
+                            arch_spec.GetTriple().setArch(llvm::Triple::thumb);
+
+                    break;
+                }
+                case llvm::ARMBuildAttrs::ABI_VFP_args:
+                {
+                    uint64_t VFPArgs = data.GetULEB128(&Offset);
+
+                    if (VFPArgs == llvm::ARMBuildAttrs::BaseAAPCS)
+                    {
+                        if (arch_spec.GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment ||
+                            arch_spec.GetTriple().getEnvironment() == llvm::Triple::EABIHF)
+                            arch_spec.GetTriple().setEnvironment(llvm::Triple::EABI);
+
+                        arch_spec.SetFlags(ArchSpec::eARM_abi_soft_float);
+                    }
+                    else if (VFPArgs == llvm::ARMBuildAttrs::HardFPAAPCS)
+                    {
+                        if (arch_spec.GetTriple().getEnvironment() == llvm::Triple::UnknownEnvironment ||
+                            arch_spec.GetTriple().getEnvironment() == llvm::Triple::EABI)
+                            arch_spec.GetTriple().setEnvironment(llvm::Triple::EABIHF);
+
+                        arch_spec.SetFlags(ArchSpec::eARM_abi_hard_float);
+                    }
+
+                    break;
+                }
+            }
+        }
+    }
+}
 
 //----------------------------------------------------------------------
 // GetSectionHeaderInfo
@@ -1648,6 +1736,18 @@ ObjectFileELF::GetSectionHeaderInfo(Sect
                     arch_spec.SetFlags (arch_flags);
                 }
 
+                if (arch_spec.GetMachine() == llvm::Triple::arm || arch_spec.GetMachine() == llvm::Triple::thumb)
+                {
+                    DataExtractor data;
+
+                    if (sheader.sh_type != SHT_ARM_ATTRIBUTES)
+                        continue;
+                    if (section_size == 0 || set_data(data, sheader.sh_offset, section_size) != section_size)
+                        continue;
+
+                    ParseARMAttributes(data, section_size, arch_spec);
+                }
+
                 if (name == g_sect_name_gnu_debuglink)
                 {
                     DataExtractor data;

Modified: lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h
URL: http://llvm.org/viewvc/llvm-project/lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h?rev=267291&r1=267290&r2=267291&view=diff
==============================================================================
--- lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h (original)
+++ lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.h Sat Apr 23 11:00:15 2016
@@ -298,6 +298,10 @@ private:
     size_t
     ParseSectionHeaders();
 
+    static void
+    ParseARMAttributes(lldb_private::DataExtractor &data, uint64_t length,
+                       lldb_private::ArchSpec &arch_spec);
+
     /// Parses the elf section headers and returns the uuid, debug link name, crc, archspec.
     static size_t
     GetSectionHeaderInfo(SectionHeaderColl &section_headers,