Add a way to grab the target options from the LTO command line.

When the command line target options were removed from the LLVM libraries, LTO
lost its ability to specify things like `-disable-fp-elim'. Add this back by
adding the command line variables to the `lto' project.
<rdar://problem/12038729>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161353 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 148 insertions, 2 deletions

diff --git a/tools/lto/LTOCodeGenerator.cpp b/tools/lto/LTOCodeGenerator.cpp
index 08139470be..e7d8b6e26d 100644
--- a/tools/lto/LTOCodeGenerator.cpp
+++ b/tools/lto/LTOCodeGenerator.cpp
@@ -46,10 +46,12 @@
 #include "llvm/ADT/StringExtras.h"
 using namespace llvm;
 
-static cl::opt<bool> DisableInline("disable-inlining", cl::init(false),
+static cl::opt<bool>
+DisableInline("disable-inlining", cl::init(false),
   cl::desc("Do not run the inliner pass"));
 
-static cl::opt<bool> DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
+static cl::opt<bool>
+DisableGVNLoadPRE("disable-gvn-loadpre", cl::init(false),
   cl::desc("Do not run the GVN load PRE pass"));
 
 const char* LTOCodeGenerator::getVersionString() {
@@ -239,6 +241,7 @@ bool LTOCodeGenerator::determineTarget(std::string& errMsg) {
     Features.getDefaultSubtargetFeatures(llvm::Triple(Triple));
     std::string FeatureStr = Features.getString();
     TargetOptions Options;
+    LTOModule::getTargetOptions(Options);
     _target = march->createTargetMachine(Triple, _mCpu, FeatureStr, Options,
                                          RelocModel, CodeModel::Default,
                                          CodeGenOpt::Aggressive);
diff --git a/tools/lto/LTOModule.cpp b/tools/lto/LTOModule.cpp
index 97b58896d2..1a55d56bac 100644
--- a/tools/lto/LTOModule.cpp
+++ b/tools/lto/LTOModule.cpp
@@ -26,6 +26,7 @@
 #include "llvm/MC/SubtargetFeature.h"
 #include "llvm/MC/MCParser/MCAsmParser.h"
 #include "llvm/Target/TargetRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.h"
@@ -37,6 +38,118 @@
 #include "llvm/ADT/Triple.h"
 using namespace llvm;
 
+static cl::opt<bool>
+EnableFPMAD("enable-fp-mad",
+  cl::desc("Enable less precise MAD instructions to be generated"),
+  cl::init(false));
+
+static cl::opt<bool>
+DisableFPElim("disable-fp-elim",
+  cl::desc("Disable frame pointer elimination optimization"),
+  cl::init(false));
+
+static cl::opt<bool>
+DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
+  cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
+  cl::init(false));
+
+static cl::opt<bool>
+EnableUnsafeFPMath("enable-unsafe-fp-math",
+  cl::desc("Enable optimizations that may decrease FP precision"),
+  cl::init(false));
+
+static cl::opt<bool>
+EnableNoInfsFPMath("enable-no-infs-fp-math",
+  cl::desc("Enable FP math optimizations that assume no +-Infs"),
+  cl::init(false));
+
+static cl::opt<bool>
+EnableNoNaNsFPMath("enable-no-nans-fp-math",
+  cl::desc("Enable FP math optimizations that assume no NaNs"),
+  cl::init(false));
+
+static cl::opt<bool>
+EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
+  cl::Hidden,
+  cl::desc("Force codegen to assume rounding mode can change dynamically"),
+  cl::init(false));
+
+static cl::opt<bool>
+GenerateSoftFloatCalls("soft-float",
+  cl::desc("Generate software floating point library calls"),
+  cl::init(false));
+
+static cl::opt<llvm::FloatABI::ABIType>
+FloatABIForCalls("float-abi",
+  cl::desc("Choose float ABI type"),
+  cl::init(FloatABI::Default),
+  cl::values(
+    clEnumValN(FloatABI::Default, "default",
+               "Target default float ABI type"),
+    clEnumValN(FloatABI::Soft, "soft",
+               "Soft float ABI (implied by -soft-float)"),
+    clEnumValN(FloatABI::Hard, "hard",
+               "Hard float ABI (uses FP registers)"),
+    clEnumValEnd));
+
+static cl::opt<llvm::FPOpFusion::FPOpFusionMode>
+FuseFPOps("fp-contract",
+  cl::desc("Enable aggresive formation of fused FP ops"),
+  cl::init(FPOpFusion::Standard),
+  cl::values(
+    clEnumValN(FPOpFusion::Fast, "fast",
+               "Fuse FP ops whenever profitable"),
+    clEnumValN(FPOpFusion::Standard, "on",
+               "Only fuse 'blessed' FP ops."),
+    clEnumValN(FPOpFusion::Strict, "off",
+               "Only fuse FP ops when the result won't be effected."),
+    clEnumValEnd));
+
+static cl::opt<bool>
+DontPlaceZerosInBSS("nozero-initialized-in-bss",
+  cl::desc("Don't place zero-initialized symbols into bss section"),
+  cl::init(false));
+
+static cl::opt<bool>
+EnableGuaranteedTailCallOpt("tailcallopt",
+  cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
+  cl::init(false));
+
+static cl::opt<bool>
+DisableTailCalls("disable-tail-calls",
+  cl::desc("Never emit tail calls"),
+  cl::init(false));
+
+static cl::opt<unsigned>
+OverrideStackAlignment("stack-alignment",
+  cl::desc("Override default stack alignment"),
+  cl::init(0));
+
+static cl::opt<bool>
+EnableRealignStack("realign-stack",
+  cl::desc("Realign stack if needed"),
+  cl::init(true));
+
+static cl::opt<std::string>
+TrapFuncName("trap-func", cl::Hidden,
+  cl::desc("Emit a call to trap function rather than a trap instruction"),
+  cl::init(""));
+
+static cl::opt<bool>
+EnablePIE("enable-pie",
+  cl::desc("Assume the creation of a position independent executable."),
+  cl::init(false));
+
+static cl::opt<bool>
+SegmentedStacks("segmented-stacks",
+  cl::desc("Use segmented stacks if possible."),
+  cl::init(false));
+
+static cl::opt<bool>
+UseInitArray("use-init-array",
+  cl::desc("Use .init_array instead of .ctors."),
+  cl::init(false));
+
 LTOModule::LTOModule(llvm::Module *m, llvm::TargetMachine *t)
   : _module(m), _target(t),
     _context(*_target->getMCAsmInfo(), *_target->getRegisterInfo(), NULL),
@@ -117,6 +230,30 @@ LTOModule *LTOModule::makeLTOModule(const void *mem, size_t length,
   return makeLTOModule(buffer.take(), errMsg);
 }
 
+void LTOModule::getTargetOptions(TargetOptions &Options) {
+  Options.LessPreciseFPMADOption = EnableFPMAD;
+  Options.NoFramePointerElim = DisableFPElim;
+  Options.NoFramePointerElimNonLeaf = DisableFPElimNonLeaf;
+  Options.AllowFPOpFusion = FuseFPOps;
+  Options.UnsafeFPMath = EnableUnsafeFPMath;
+  Options.NoInfsFPMath = EnableNoInfsFPMath;
+  Options.NoNaNsFPMath = EnableNoNaNsFPMath;
+  Options.HonorSignDependentRoundingFPMathOption =
+    EnableHonorSignDependentRoundingFPMath;
+  Options.UseSoftFloat = GenerateSoftFloatCalls;
+  if (FloatABIForCalls != FloatABI::Default)
+    Options.FloatABIType = FloatABIForCalls;
+  Options.NoZerosInBSS = DontPlaceZerosInBSS;
+  Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
+  Options.DisableTailCalls = DisableTailCalls;
+  Options.StackAlignmentOverride = OverrideStackAlignment;
+  Options.RealignStack = EnableRealignStack;
+  Options.TrapFuncName = TrapFuncName;
+  Options.PositionIndependentExecutable = EnablePIE;
+  Options.EnableSegmentedStacks = SegmentedStacks;
+  Options.UseInitArray = UseInitArray;
+}
+
 LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
                                     std::string &errMsg) {
   static bool Initialized = false;
@@ -150,6 +287,7 @@ LTOModule *LTOModule::makeLTOModule(MemoryBuffer *buffer,
   std::string FeatureStr = Features.getString();
   std::string CPU;
   TargetOptions Options;
+  getTargetOptions(Options);
   TargetMachine *target = march->createTargetMachine(Triple, CPU, FeatureStr,
                                                      Options);
   LTOModule *Ret = new LTOModule(m.take(), target);
diff --git a/tools/lto/LTOModule.h b/tools/lto/LTOModule.h
index cafb927abf..8e52206b5b 100644
--- a/tools/lto/LTOModule.h
+++ b/tools/lto/LTOModule.h
@@ -29,6 +29,7 @@ namespace llvm {
   class Function;
   class GlobalValue;
   class MemoryBuffer;
+  class TargetOptions;
   class Value;
 }
 
@@ -126,6 +127,10 @@ public:
     return _asm_undefines;
   }
 
+  /// getTargetOptions - Fill the TargetOptions object with the options
+  /// specified on the command line.
+  static void getTargetOptions(llvm::TargetOptions &Options);
+
 private:
   /// parseSymbols - Parse the symbols from the module and model-level ASM and
   /// add them to either the defined or undefined lists.