[X86] Disabling PLT in Regcall CC Functions
According to psABI, PLT stub clobbers XMM8-XMM15.
In Regcall calling convention those registers are used for passing parameters.
Thus we need to prevent lazy binding in Regcall.
Differential Revision: https://reviews.llvm.org/D32430
llvm-svn: 302124
diff --git a/llvm/lib/Target/X86/X86Subtarget.cpp b/llvm/lib/Target/X86/X86Subtarget.cpp
index 9ab751e..d66d39d 100644
--- a/llvm/lib/Target/X86/X86Subtarget.cpp
+++ b/llvm/lib/Target/X86/X86Subtarget.cpp
@@ -139,12 +139,18 @@
return X86II::MO_NO_FLAG;
assert(!isTargetCOFF());
+ const Function *F = dyn_cast_or_null<Function>(GV);
- if (isTargetELF())
+ if (isTargetELF()) {
+ if (is64Bit() && F && (CallingConv::X86_RegCall == F->getCallingConv()))
+ // According to psABI, PLT stub clobbers XMM8-XMM15.
+ // In Regcall calling convention those registers are used for passing
+ // parameters. Thus we need to prevent lazy binding in Regcall.
+ return X86II::MO_GOTPCREL;
return X86II::MO_PLT;
+ }
if (is64Bit()) {
- auto *F = dyn_cast_or_null<Function>(GV);
if (F && F->hasFnAttribute(Attribute::NonLazyBind))
// If the function is marked as non-lazy, generate an indirect call
// which loads from the GOT directly. This avoids runtime overhead