[Sparc] Add Soft Float support

This change adds support for software floating point operations for Sparc targets.

This is the first in a set of patches to enable software floating point on Sparc. The next patch will enable the option to be used with Clang.

Differential Revision: http://reviews.llvm.org/D19265

llvm-svn: 269892

1 files changed, 36 insertions, 2 deletions

diff --git a/llvm/lib/Target/Sparc/SparcTargetMachine.cpp b/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
index fa6cc73c529..6e75c634d0e 100644
--- a/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
+++ b/llvm/lib/Target/Sparc/SparcTargetMachine.cpp
@@ -62,13 +62,47 @@ SparcTargetMachine::SparcTargetMachine(const Target &T, const Triple &TT,
                                        CodeGenOpt::Level OL, bool is64bit)
     : LLVMTargetMachine(T, computeDataLayout(TT, is64bit), TT, CPU, FS, Options,
                         RM, CM, OL),
-      TLOF(make_unique<SparcELFTargetObjectFile>()),
-      Subtarget(TT, CPU, FS, *this, is64bit) {
+      TLOF(make_unique<SparcELFTargetObjectFile>()) {
   initAsmInfo();
+  this->is64Bit = is64bit;
 }
 
 SparcTargetMachine::~SparcTargetMachine() {}
 
+const SparcSubtarget * 
+SparcTargetMachine::getSubtargetImpl(const Function &F) const {
+  Attribute CPUAttr = F.getFnAttribute("target-cpu");
+  Attribute FSAttr = F.getFnAttribute("target-features");
+
+  std::string CPU = !CPUAttr.hasAttribute(Attribute::None)
+                        ? CPUAttr.getValueAsString().str()
+                        : TargetCPU;
+  std::string FS = !FSAttr.hasAttribute(Attribute::None)
+                       ? FSAttr.getValueAsString().str()
+                       : TargetFS;
+
+  // FIXME: This is related to the code below to reset the target options,
+  // we need to know whether or not the soft float flag is set on the
+  // function, so we can enable it as a subtarget feature.
+  bool softFloat =
+      F.hasFnAttribute("use-soft-float") &&
+      F.getFnAttribute("use-soft-float").getValueAsString() == "true";
+
+  if (softFloat)         
+    FS += FS.empty() ? "+soft-float" : ",+soft-float";
+
+  auto &I = SubtargetMap[CPU + FS];
+  if (!I) {
+    // This needs to be done before we create a new subtarget since any
+    // creation will depend on the TM and the code generation flags on the
+    // function that reside in TargetOptions.
+    resetTargetOptions(F);
+    I = llvm::make_unique<SparcSubtarget>(TargetTriple, CPU, FS, *this,
+                                          this->is64Bit);
+  }
+  return I.get();
+}
+
 namespace {
 /// Sparc Code Generator Pass Configuration Options.
 class SparcPassConfig : public TargetPassConfig {