[lldb-dev] [PATCH] Dealing with CPU subtypes (architecture variants)
Matthew Gardiner
mg11 at csr.com
Tue Aug 26 05:56:39 PDT 2014
Hi folks,
The kalimba architecture has a number of variants. The ones of interest
to me being 3, 4 and 5. I have added some additional entries to the
g_elf_arch_entries to describe these variants. However, up until now, no
subtypes (architecture variants), for ELF objectfiles exist in lldb. So
I've found it necessary to modify the invocation of
ArchSpec.SetArchitecture from ObjectFileELF to deal with this.
Now the kalimba variant specification can be deduced by parsing the
e_flags field from the ELF header. So I've written a specific routine
which extracts the variant spec from the e_flags. What I'm not too happy
about, and would appreciate lldb-dev's opinion on, is if it is ok for
the extraction routine (kalimbaVariantFromElfFlags) to remain in
ObjectFileELF.cpp? If not, where should the routine go? Furthermore how
do I get any new files into the xcode project file, given that I have no
xcode system - shall I just change the make and cmake build and rely on
an Apple person to fix any xcode build breakage?
Below is a diff of what I have done recognize kalimba variants, basically:
1. add new entries to ArchSpec::enum Core, and g_elf_arch_entries
2. supply routine to extract the kalimba variant from the e_flags
3. if e_machine == EM_CSR_KALIMBA, extract the kalimba variant and pass
it to SetArchitecture as the cpu sub type.
--- a/include/lldb/Core/ArchSpec.h 2014-08-18
+++ b/include/lldb/Core/ArchSpec.h 2014-08-18
@@ -103,6 +103,9 @@
eCore_uknownMach64,
eCore_kalimba,
+ eCore_kalimba3,
+ eCore_kalimba4,
+ eCore_kalimba5,
kNumCores,
--- a/source/Core/ArchSpec.cpp 2014-08-05
+++ b/source/Core/ArchSpec.cpp 2014-08-05
@@ -115,7 +115,10 @@
{ eByteOrderLittle, 4, 4, 4 , llvm::Triple::UnknownArch ,
ArchSpec::eCore_uknownMach32 , "unknown-mach-32" },
{ eByteOrderLittle, 8, 4, 4 , llvm::Triple::UnknownArch ,
ArchSpec::eCore_uknownMach64 , "unknown-mach-64" },
- { eByteOrderLittle, 4, 1, 1 , llvm::Triple::kalimba ,
ArchSpec::eCore_kalimba , "kalimba" }
+ { eByteOrderLittle, 4, 1, 1 , llvm::Triple::kalimba ,
ArchSpec::eCore_kalimba , "kalimba" },
+ { eByteOrderLittle, 4, 1, 1 , llvm::Triple::kalimba ,
ArchSpec::eCore_kalimba3 , "kalimba3" },
+ { eByteOrderLittle, 4, 1, 1 , llvm::Triple::kalimba ,
ArchSpec::eCore_kalimba4 , "kalimba4" },
+ { eByteOrderLittle, 4, 1, 1 , llvm::Triple::kalimba ,
ArchSpec::eCore_kalimba5 , "kalimba5" }
};
// Ensure that we have an entry in the g_core_definitions for each
core. If you comment out an entry above,
@@ -257,7 +260,10 @@
{ ArchSpec::eCore_x86_64_x86_64 , llvm::ELF::EM_X86_64 ,
LLDB_INVALID_CPUTYPE, 0xFFFFFFFFu, 0xFFFFFFFFu }, // AMD64
{ ArchSpec::eCore_mips64 , llvm::ELF::EM_MIPS ,
LLDB_INVALID_CPUTYPE, 0xFFFFFFFFu, 0xFFFFFFFFu }, // MIPS
{ ArchSpec::eCore_hexagon_generic , llvm::ELF::EM_HEXAGON,
LLDB_INVALID_CPUTYPE, 0xFFFFFFFFu, 0xFFFFFFFFu }, // HEXAGON
- { ArchSpec::eCore_kalimba , llvm::ELF::EM_CSR_KALIMBA,
LLDB_INVALID_CPUTYPE, 0xFFFFFFFFu, 0xFFFFFFFFu } // KALIMBA
+ { ArchSpec::eCore_kalimba , llvm::ELF::EM_CSR_KALIMBA,
LLDB_INVALID_CPUTYPE, 0xFFFFFFFFu, 0xFFFFFFFFu }, // KALIMBA
+ { ArchSpec::eCore_kalimba3 , llvm::ELF::EM_CSR_KALIMBA, 3,
0xFFFFFFFFu, 0xFFFFFFFFu }, // KALIMBA
+ { ArchSpec::eCore_kalimba4 , llvm::ELF::EM_CSR_KALIMBA, 4,
0xFFFFFFFFu, 0xFFFFFFFFu }, // KALIMBA
+ { ArchSpec::eCore_kalimba5 , llvm::ELF::EM_CSR_KALIMBA, 5,
0xFFFFFFFFu, 0xFFFFFFFFu } // KALIMBA
};
--- a/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp 2014-07-22
+++ b/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp 2014-07-22
@@ -257,6 +257,27 @@
return true;
}
+static uint32_t
+kalimbaVariantFromElfFlags(const elf::elf_word e_flags)
+{
+ const uint32_t dsp_rev = e_flags & 0xFF;
+ uint32_t kal_arch_variant = LLDB_INVALID_CPUTYPE;
+ switch(dsp_rev)
+ {
+ // TODO(mg11) Support more variants
+ case 10:
+ kal_arch_variant = 3;
+ break;
+ case 14:
+ kal_arch_variant = 4;
+ break;
+ default:
+ break;
+ }
+ return kal_arch_variant;
+}
+
+
// Arbitrary constant used as UUID prefix for core files.
const uint32_t
ObjectFileELF::g_core_uuid_magic(0xE210C);
@@ -544,9 +565,15 @@
{
ModuleSpec spec;
spec.GetFileSpec() = file;
+
+ const uint32_t sub_type =
+ llvm::ELF::EM_CSR_KALIMBA == header.e_machine ?
+ kalimbaVariantFromElfFlags(header.e_flags) :
+ LLDB_INVALID_CPUTYPE;
spec.GetArchitecture().SetArchitecture(eArchTypeELF,
header.e_machine,
- LLDB_INVALID_CPUTYPE);
+ sub_type);
+
if (spec.GetArchitecture().IsValid())
{
llvm::Triple::OSType ostype;
@@ -1269,7 +1296,12 @@
// We'll refine this with note data as we parse the notes.
if (arch_spec.GetTriple ().getOS () ==
llvm::Triple::OSType::UnknownOS)
{
- arch_spec.SetArchitecture (eArchTypeELF, header.e_machine,
LLDB_INVALID_CPUTYPE);
+ const uint32_t sub_type =
+ llvm::ELF::EM_CSR_KALIMBA == header.e_machine ?
+ kalimbaVariantFromElfFlags(header.e_flags) :
+ LLDB_INVALID_CPUTYPE;
+ arch_spec.SetArchitecture (eArchTypeELF, header.e_machine,
sub_type);
+
switch (arch_spec.GetAddressByteSize())
{
case 4:
I'd appreciate people's opinion on this diff, before I commit anything.
(The reason I need to know the variant type, is because some kalimba
variants have a different notion of "byte-size" i.e. minimum addressable
unit. For example for kalimba3 the minimum addressable unit from the
data bus is 24-bits, whereas for kalimba4 it is the more conventional
8-bits. I'd like to reserve the problems/challenges this presents for
me, regarding my kalimba lldb port, to a future email).
thanks
Matt
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