+
+ // Windows stack unwinder gets confused when execution flow "falls through"
+ // after a call to 'noreturn' function.
+ // To prevent that, we emit a trap for 'unreachable' IR instructions.
+ // (which on X86, happens to be the 'ud2' instruction)
+ if (Subtarget.isTargetWin64())
+ this->Options.TrapUnreachable = true;
+
+ initAsmInfo();
+}
+
+const X86Subtarget *
+X86TargetMachine::getSubtargetImpl(const Function &F) const {
+ AttributeSet FnAttrs = F.getAttributes();
+ Attribute CPUAttr =
+ FnAttrs.getAttribute(AttributeSet::FunctionIndex, "target-cpu");
+ Attribute FSAttr =
+ FnAttrs.getAttribute(AttributeSet::FunctionIndex, "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 before we can generate a subtarget. We also need to use
+ // it as a key for the subtarget since that can be the only difference
+ // between two functions.
+ Attribute SFAttr =
+ FnAttrs.getAttribute(AttributeSet::FunctionIndex, "use-soft-float");
+ bool SoftFloat = !SFAttr.hasAttribute(Attribute::None)
+ ? SFAttr.getValueAsString() == "true"
+ : Options.UseSoftFloat;
+
+ auto &I = SubtargetMap[CPU + FS + (SoftFloat ? "use-soft-float=true"
+ : "use-soft-float=false")];
+ 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<X86Subtarget>(TargetTriple, CPU, FS, *this,
+ Options.StackAlignmentOverride);
+ }
+ return I.get();