> On Mar 19, 2015, at 12:15 PM, Ted Woodward <ted.woodw...@codeaurora.org>
> wrote:
>
> I've got a Hexagon platform, that launches the Hexagon simulator and is used
> for standalone development. Now I'm working on supporting Hexagon Linux, but
> it's not choosing the Linux platform, instead it's choosing the Hexagon
> platform.
>
> I want LLDB to use the Hexagon Platform if my executable's triple is
> "hexagon-unknown-elf" (which is really hexagon-unknown-unknown) and use the
> Linux platform if my executable's triple is "hexagon-unknown-linux".
>
>
> First problem:
> "target create" doesn't search platforms for one matching the executable's
> triple. It used to, but when TargetList::CreateTarget was switched to call
> CreateTargetInternal, "target create" was changed to call the method that
> takes an ArchSpec instead of a triple. This method doesn't search for a
> compatible Platform, but instead chooses the current Platform.
>
> Is this intended behavior?
No. Sounds like you have an old snapshot of LLDB. The current one was recently
fixed to search for the platform with revision 216115.
>
> Second problem:
> I change DoExecute() in CommandObjectTarget.cpp to call the ArchSpec version
> if the ArchSpec is valid, and the triple version if it is not. This has LLDB
> going through platforms to find a match, but there's another problem when it
> gets to PlatformLinux. PlatformLinux::GetSupportedArchitectureAtIndex() will
> only return host architectures.
This is a bug and should be fixed with code below...
> So in my case, running on Windows, it
> returns x86_64-pc-windows-msvc or i386-pc-windows-msvc. Neither is a match
> for Linux.
>
> Shouldn't the Linux platform match anything with a triple *-*-linux? Or does
> the platform not matter if I'm just going to use gdb-remote to connect to
> gdbserver or LLGS on a remote Hexagon Linux board?
So a platform can say what architectures it supports. This is how we match
architectures up to a binary that is supplied. Each platform should give an
exhaustive list of the architectures they support.
The current code is:
bool
PlatformLinux::GetSupportedArchitectureAtIndex (uint32_t idx, ArchSpec &arch)
{
if (idx == 0)
{
arch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
return arch.IsValid();
}
else if (idx == 1)
{
// If the default host architecture is 64-bit, look for a 32-bit variant
ArchSpec hostArch =
HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit())
{
arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
return arch.IsValid();
}
}
return false;
}
This is only correct if Platform::IsHost() returns true. Otherwise linux will
need to say all architectures that is supports:
x86_64-*-linux
i386-*-linux
arm*-*-linux
aarch64-*-linux
mips64-*linux
The "*" above for the vendor should be set an an "unspecified unknown". So the
code should be:
bool
PlatformLinux::GetSupportedArchitectureAtIndex (uint32_t idx, ArchSpec &arch)
{
if (IsHost())
{
if (idx == 0)
{
arch = HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
return arch.IsValid();
}
else if (idx == 1)
{
// If the default host architecture is 64-bit, look for a 32-bit
variant
ArchSpec hostArch =
HostInfo::GetArchitecture(HostInfo::eArchKindDefault);
if (hostArch.IsValid() && hostArch.GetTriple().isArch64Bit())
{
arch = HostInfo::GetArchitecture(HostInfo::eArchKind32);
return arch.IsValid();
}
}
}
else
{
llvm::Triple triple;
// Set the OS to linux
triple.setOS(llvm::Triple::Linux);
// Set the architecture
switch (idx)
{
case 0: arch.setArchName("x86_64"); break;
case 1: arch.setArchName("i386"); break;
case 2: arch.setArchName("arm"); break;
case 3: arch.setArchName("aarch64"); break;
case 4: arch.setArchName("mips64"); break;
case 5: arch.setArchName("hexagon"); break;
default: return false;
}
// Leave the vendor as "llvm::Triple:UnknownVendor" and don't specify
the vendor by
// calling triple.SetVendorName("unknown") so that it is a "unspecified
unknown".
// This means when someone calls triple.GetVendorName() it will return
an empty string
// which indicates that the vendor can be set when two architectures
are merged
// Now set the triple into "arch" and return true
arch.SetTriple(triple);
return true;
}
return false;
}
Then things should work a bit better for you.
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