[llvm-commits] [llvm] r139125 - in /llvm/trunk/lib/Target: ARM/ARM.td ARM/ARMInstrInfo.td ARM/ARMSubtarget.cpp ARM/ARMSubtarget.h ARM/MCTargetDesc/ARMMCTargetDesc.cpp X86/MCTargetDesc/X86MCTargetDesc.cpp X86/X86.td X86/X86InstrInfo.td X86/X86Subtarget.cpp X86/X86Subtarget.h

Chris Lattner clattner at apple.com
Thu Sep 8 22:44:47 PDT 2011


On Sep 6, 2011, at 10:05 AM, Jim Grosbach wrote:

> Hi Nick,
> 
> I have a few concerns about this that hopefully won't be too hard to alleviate. On the more trite side, we generally try to keep the nomenclature descriptive of purpose rather than of use. This patch names the sub-target feature according to purpose (native client) and doesn't give any indication of what it actually does. Is this really a sub-target feature at all? Honestly, my general impression is that this is more accurately a target platform in the triple akin to Linux or Darwin. For example, thumbv7-unknown-nacl. Assuming so (and it looks like that is indeed how it's specified?), why isn't querying the triple directly a-la ARMSubtarget->isTargetDarwin(), sufficient? Lastly, speculating here as this patch doesn't go into these details, but be very careful with alignment changes in code sections, as the ARM backend is very sensitive to small changes. Specifically, the constant island pass tracks instruction alignment and relative distances as exactly as it can, and will!
  n!
> eed to be taught how to deal with these changes.

I agree in principle, but I can see it go both ways.  Note that 64-bit support is also a "subtarget feature" which is also very odd, but convenient.

That said, if "NaCL mode" is really just normal codegen plus a few tweaks, it would be much better to add subtarget features for the tweaks, and nacl mode could enable those tweaks.  This respect is very different than 64-bit support.

-Chris

> 
> -Jim
> 
> On Sep 5, 2011, at 2:51 PM, Nick Lewycky wrote:
> 
>> Author: nicholas
>> Date: Mon Sep  5 16:51:43 2011
>> New Revision: 139125
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=139125&view=rev
>> Log:
>> Add a new MC bit for NaCl (Native Client) mode. NaCl requires that certain
>> instructions are more aligned than the CPU requires, and adds some additional
>> directives, to follow in future patches. Patch by David Meyer!
>> 
>> Modified:
>>   llvm/trunk/lib/Target/ARM/ARM.td
>>   llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
>>   llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
>>   llvm/trunk/lib/Target/ARM/ARMSubtarget.h
>>   llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
>>   llvm/trunk/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
>>   llvm/trunk/lib/Target/X86/X86.td
>>   llvm/trunk/lib/Target/X86/X86InstrInfo.td
>>   llvm/trunk/lib/Target/X86/X86Subtarget.cpp
>>   llvm/trunk/lib/Target/X86/X86Subtarget.h
>> 
>> Modified: llvm/trunk/lib/Target/ARM/ARM.td
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARM.td?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/ARM.td (original)
>> +++ llvm/trunk/lib/Target/ARM/ARM.td Mon Sep  5 16:51:43 2011
>> @@ -23,6 +23,9 @@
>> def ModeThumb  : SubtargetFeature<"thumb-mode", "InThumbMode", "true",
>>                                  "Thumb mode">;
>> 
>> +def ModeNaCl   : SubtargetFeature<"nacl-mode", "InNaClMode", "true",
>> +                                  "Native client mode">;
>> +
>> //===----------------------------------------------------------------------===//
>> // ARM Subtarget features.
>> //
>> 
>> Modified: llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrInfo.td?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/ARMInstrInfo.td (original)
>> +++ llvm/trunk/lib/Target/ARM/ARMInstrInfo.td Mon Sep  5 16:51:43 2011
>> @@ -209,6 +209,8 @@
>>                                 AssemblerPredicate<"!ModeThumb">;
>> def IsDarwin         : Predicate<"Subtarget->isTargetDarwin()">;
>> def IsNotDarwin      : Predicate<"!Subtarget->isTargetDarwin()">;
>> +def IsNaCl           : Predicate<"Subtarget->isTargetNaCl()">,
>> +                                 AssemblerPredicate<"ModeNaCl">;
>> 
>> // FIXME: Eventually this will be just "hasV6T2Ops".
>> def UseMovt          : Predicate<"Subtarget->useMovt()">;
>> 
>> Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp (original)
>> +++ llvm/trunk/lib/Target/ARM/ARMSubtarget.cpp Mon Sep  5 16:51:43 2011
>> @@ -53,6 +53,7 @@
>>  , HasVMLxForwarding(false)
>>  , SlowFPBrcc(false)
>>  , InThumbMode(false)
>> +  , InNaClMode(false)
>>  , HasThumb2(false)
>>  , NoARM(false)
>>  , PostRAScheduler(false)
>> 
>> Modified: llvm/trunk/lib/Target/ARM/ARMSubtarget.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMSubtarget.h?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/ARMSubtarget.h (original)
>> +++ llvm/trunk/lib/Target/ARM/ARMSubtarget.h Mon Sep  5 16:51:43 2011
>> @@ -70,6 +70,9 @@
>>  /// InThumbMode - True if compiling for Thumb, false for ARM.
>>  bool InThumbMode;
>> 
>> +  /// InNaClMode - True if targeting Native Client
>> +  bool InNaClMode;
>> +
>>  /// HasThumb2 - True if Thumb2 instructions are supported.
>>  bool HasThumb2;
>> 
>> @@ -209,6 +212,9 @@
>>  const Triple &getTargetTriple() const { return TargetTriple; }
>> 
>>  bool isTargetDarwin() const { return TargetTriple.isOSDarwin(); }
>> +  bool isTargetNaCl() const {
>> +    return TargetTriple.getOS() == Triple::NativeClient;
>> +  }
>>  bool isTargetELF() const { return !isTargetDarwin(); }
>> 
>>  bool isAPCS_ABI() const { return TargetABI == ARM_ABI_APCS; }
>> 
>> Modified: llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp (original)
>> +++ llvm/trunk/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp Mon Sep  5 16:51:43 2011
>> @@ -86,6 +86,14 @@
>>      ARMArchFeature += ",+thumb-mode";
>>  }
>> 
>> +  Triple TheTriple(TT);
>> +  if (TheTriple.getOS() == Triple::NativeClient) {
>> +    if (ARMArchFeature.empty())
>> +      ARMArchFeature = "+nacl-mode";
>> +    else
>> +      ARMArchFeature += ",+nacl-mode";
>> +  }
>> +
>>  return ARMArchFeature;
>> }
>> 
>> 
>> Modified: llvm/trunk/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp (original)
>> +++ llvm/trunk/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp Mon Sep  5 16:51:43 2011
>> @@ -40,9 +40,16 @@
>> 
>> std::string X86_MC::ParseX86Triple(StringRef TT) {
>>  Triple TheTriple(TT);
>> +  std::string FS;
>>  if (TheTriple.getArch() == Triple::x86_64)
>> -    return "+64bit-mode";
>> -  return "-64bit-mode";
>> +    FS = "+64bit-mode";
>> +  else
>> +    FS = "-64bit-mode";
>> +  if (TheTriple.getOS() == Triple::NativeClient)
>> +    FS += ",+nacl-mode";
>> +  else
>> +    FS += ",-nacl-mode";
>> +  return FS;
>> }
>> 
>> /// GetCpuIDAndInfo - Execute the specified cpuid and return the 4 values in the
>> 
>> Modified: llvm/trunk/lib/Target/X86/X86.td
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86.td?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/X86.td (original)
>> +++ llvm/trunk/lib/Target/X86/X86.td Mon Sep  5 16:51:43 2011
>> @@ -23,6 +23,9 @@
>> def Mode64Bit : SubtargetFeature<"64bit-mode", "In64BitMode", "true",
>>                                  "64-bit mode (x86_64)">;
>> 
>> +def ModeNaCl  : SubtargetFeature<"nacl-mode", "InNaClMode", "true",
>> +                                 "Native Client mode">;
>> +
>> //===----------------------------------------------------------------------===//
>> // X86 Subtarget features.
>> //===----------------------------------------------------------------------===//
>> 
>> Modified: llvm/trunk/lib/Target/X86/X86InstrInfo.td
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86InstrInfo.td?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/X86InstrInfo.td (original)
>> +++ llvm/trunk/lib/Target/X86/X86InstrInfo.td Mon Sep  5 16:51:43 2011
>> @@ -482,6 +482,14 @@
>>                             AssemblerPredicate<"Mode64Bit">;
>> def IsWin64      : Predicate<"Subtarget->isTargetWin64()">;
>> def NotWin64     : Predicate<"!Subtarget->isTargetWin64()">;
>> +def IsNaCl       : Predicate<"Subtarget->isTargetNaCl()">,
>> +                             AssemblerPredicate<"ModeNaCl">;
>> +def IsNaCl32     : Predicate<"Subtarget->isTargetNaCl32()">,
>> +                             AssemblerPredicate<"ModeNaCl,!Mode64Bit">;
>> +def IsNaCl64     : Predicate<"Subtarget->isTargetNaCl64()">,
>> +                             AssemblerPredicate<"ModeNaCl,Mode64Bit">;
>> +def NotNaCl      : Predicate<"!Subtarget->isTargetNaCl()">,
>> +                             AssemblerPredicate<"!ModeNaCl">;
>> def SmallCode    : Predicate<"TM.getCodeModel() == CodeModel::Small">;
>> def KernelCode   : Predicate<"TM.getCodeModel() == CodeModel::Kernel">;
>> def FarData      : Predicate<"TM.getCodeModel() != CodeModel::Small &&"
>> 
>> Modified: llvm/trunk/lib/Target/X86/X86Subtarget.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.cpp?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/X86Subtarget.cpp (original)
>> +++ llvm/trunk/lib/Target/X86/X86Subtarget.cpp Mon Sep  5 16:51:43 2011
>> @@ -260,7 +260,8 @@
>>  // FIXME: this is a known good value for Yonah. How about others?
>>  , MaxInlineSizeThreshold(128)
>>  , TargetTriple(TT)
>> -  , In64BitMode(is64Bit) {
>> +  , In64BitMode(is64Bit)
>> +  , InNaClMode(false) {
>>  // Determine default and user specified characteristics
>>  if (!FS.empty() || !CPU.empty()) {
>>    std::string CPUName = CPU;
>> @@ -306,6 +307,11 @@
>>  if (In64BitMode)
>>    ToggleFeature(X86::Mode64Bit);
>> 
>> +  if (isTargetNaCl()) {
>> +    InNaClMode = true;
>> +    ToggleFeature(X86::ModeNaCl);
>> +  }
>> +
>>  if (HasAVX)
>>    X86SSELevel = NoMMXSSE;
>> 
>> 
>> Modified: llvm/trunk/lib/Target/X86/X86Subtarget.h
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Subtarget.h?rev=139125&r1=139124&r2=139125&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/Target/X86/X86Subtarget.h (original)
>> +++ llvm/trunk/lib/Target/X86/X86Subtarget.h Mon Sep  5 16:51:43 2011
>> @@ -119,6 +119,9 @@
>>  /// In64BitMode - True if compiling for 64-bit, false for 32-bit.
>>  bool In64BitMode;
>> 
>> +  /// InNaClMode - True if compiling for Native Client target.
>> +  bool InNaClMode;
>> +
>> public:
>> 
>>  /// This constructor initializes the data members to match that
>> @@ -190,6 +193,11 @@
>>    return !isTargetDarwin() && !isTargetWindows() && !isTargetCygMing();
>>  }
>>  bool isTargetLinux() const { return TargetTriple.getOS() == Triple::Linux; }
>> +  bool isTargetNaCl() const {
>> +    return TargetTriple.getOS() == Triple::NativeClient;
>> +  }
>> +  bool isTargetNaCl32() const { return isTargetNaCl() && !is64Bit(); }
>> +  bool isTargetNaCl64() const { return isTargetNaCl() && is64Bit(); }
>> 
>>  bool isTargetWindows() const { return TargetTriple.getOS() == Triple::Win32; }
>>  bool isTargetMingw() const { return TargetTriple.getOS() == Triple::MinGW32; }
>> 
>> 
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