ARM: HFAs must be passed in consecutive registers
When using the ARM AAPCS, HFAs (Homogeneous Floating-point Aggregates) must
be passed in a block of consecutive floating-point registers, or on the stack.
This means that unused floating-point registers cannot be back-filled with
part of an HFA, however this can currently happen. This patch, along with the
corresponding clang patch (http://reviews.llvm.org/D3083) prevents this.
llvm-svn: 208413
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 925b469..e483278 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -43,6 +43,7 @@
#include "llvm/IR/Type.h"
#include "llvm/MC/MCSectionMachO.h"
#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetOptions.h"
@@ -1211,40 +1212,58 @@
#include "ARMGenCallingConv.inc"
-/// CCAssignFnForNode - Selects the correct CCAssignFn for a the
-/// given CallingConvention value.
-CCAssignFn *ARMTargetLowering::CCAssignFnForNode(CallingConv::ID CC,
- bool Return,
- bool isVarArg) const {
+/// getEffectiveCallingConv - Get the effective calling convention, taking into
+/// account presence of floating point hardware and calling convention
+/// limitations, such as support for variadic functions.
+CallingConv::ID
+ARMTargetLowering::getEffectiveCallingConv(CallingConv::ID CC,
+ bool isVarArg) const {
switch (CC) {
default:
llvm_unreachable("Unsupported calling convention");
- case CallingConv::Fast:
- if (Subtarget->hasVFP2() && !isVarArg) {
- if (!Subtarget->isAAPCS_ABI())
- return (Return ? RetFastCC_ARM_APCS : FastCC_ARM_APCS);
- // For AAPCS ABI targets, just use VFP variant of the calling convention.
- return (Return ? RetCC_ARM_AAPCS_VFP : CC_ARM_AAPCS_VFP);
- }
- // Fallthrough
- case CallingConv::C: {
- // Use target triple & subtarget features to do actual dispatch.
+ case CallingConv::ARM_AAPCS:
+ case CallingConv::ARM_APCS:
+ case CallingConv::GHC:
+ return CC;
+ case CallingConv::ARM_AAPCS_VFP:
+ return isVarArg ? CallingConv::ARM_AAPCS : CallingConv::ARM_AAPCS_VFP;
+ case CallingConv::C:
if (!Subtarget->isAAPCS_ABI())
- return (Return ? RetCC_ARM_APCS : CC_ARM_APCS);
+ return CallingConv::ARM_APCS;
else if (Subtarget->hasVFP2() &&
getTargetMachine().Options.FloatABIType == FloatABI::Hard &&
!isVarArg)
- return (Return ? RetCC_ARM_AAPCS_VFP : CC_ARM_AAPCS_VFP);
- return (Return ? RetCC_ARM_AAPCS : CC_ARM_AAPCS);
+ return CallingConv::ARM_AAPCS_VFP;
+ else
+ return CallingConv::ARM_AAPCS;
+ case CallingConv::Fast:
+ if (!Subtarget->isAAPCS_ABI()) {
+ if (Subtarget->hasVFP2() && !isVarArg)
+ return CallingConv::Fast;
+ return CallingConv::ARM_APCS;
+ } else if (Subtarget->hasVFP2() && !isVarArg)
+ return CallingConv::ARM_AAPCS_VFP;
+ else
+ return CallingConv::ARM_AAPCS;
}
- case CallingConv::ARM_AAPCS_VFP:
- if (!isVarArg)
- return (Return ? RetCC_ARM_AAPCS_VFP : CC_ARM_AAPCS_VFP);
- // Fallthrough
- case CallingConv::ARM_AAPCS:
- return (Return ? RetCC_ARM_AAPCS : CC_ARM_AAPCS);
+}
+
+/// CCAssignFnForNode - Selects the correct CCAssignFn for the given
+/// CallingConvention.
+CCAssignFn *ARMTargetLowering::CCAssignFnForNode(CallingConv::ID CC,
+ bool Return,
+ bool isVarArg) const {
+ switch (getEffectiveCallingConv(CC, isVarArg)) {
+ default:
+ llvm_unreachable("Unsupported calling convention");
case CallingConv::ARM_APCS:
return (Return ? RetCC_ARM_APCS : CC_ARM_APCS);
+ case CallingConv::ARM_AAPCS:
+ return (Return ? RetCC_ARM_AAPCS : CC_ARM_AAPCS);
+ case CallingConv::ARM_AAPCS_VFP:
+ return (Return ? RetCC_ARM_AAPCS_VFP : CC_ARM_AAPCS_VFP);
+ case CallingConv::Fast:
+ return (Return ? RetFastCC_ARM_APCS : FastCC_ARM_APCS);
case CallingConv::GHC:
return (Return ? RetCC_ARM_APCS : CC_ARM_APCS_GHC);
}
@@ -10628,3 +10647,77 @@
Val, Strex->getFunctionType()->getParamType(0)),
Addr);
}
+
+enum HABaseType {
+ HA_UNKNOWN = 0,
+ HA_FLOAT,
+ HA_DOUBLE,
+ HA_VECT64,
+ HA_VECT128
+};
+
+static bool isHomogeneousAggregate(Type *Ty, HABaseType &Base,
+ uint64_t &Members) {
+ if (const StructType *ST = dyn_cast<StructType>(Ty)) {
+ for (unsigned i = 0; i < ST->getNumElements(); ++i) {
+ uint64_t SubMembers = 0;
+ if (!isHomogeneousAggregate(ST->getElementType(i), Base, SubMembers))
+ return false;
+ Members += SubMembers;
+ }
+ } else if (const ArrayType *AT = dyn_cast<ArrayType>(Ty)) {
+ uint64_t SubMembers = 0;
+ if (!isHomogeneousAggregate(AT->getElementType(), Base, SubMembers))
+ return false;
+ Members += SubMembers * AT->getNumElements();
+ } else if (Ty->isFloatTy()) {
+ if (Base != HA_UNKNOWN && Base != HA_FLOAT)
+ return false;
+ Members = 1;
+ Base = HA_FLOAT;
+ } else if (Ty->isDoubleTy()) {
+ if (Base != HA_UNKNOWN && Base != HA_DOUBLE)
+ return false;
+ Members = 1;
+ Base = HA_DOUBLE;
+ } else if (const VectorType *VT = dyn_cast<VectorType>(Ty)) {
+ Members = 1;
+ switch (Base) {
+ case HA_FLOAT:
+ case HA_DOUBLE:
+ return false;
+ case HA_VECT64:
+ return VT->getBitWidth() == 64;
+ case HA_VECT128:
+ return VT->getBitWidth() == 128;
+ case HA_UNKNOWN:
+ switch (VT->getBitWidth()) {
+ case 64:
+ Base = HA_VECT64;
+ return true;
+ case 128:
+ Base = HA_VECT128;
+ return true;
+ default:
+ return false;
+ }
+ }
+ }
+
+ return (Members > 0 && Members <= 4);
+}
+
+/// \brief Return true if a type is an AAPCS-VFP homogeneous aggregate.
+bool ARMTargetLowering::functionArgumentNeedsConsecutiveRegisters(
+ Type *Ty, CallingConv::ID CallConv, bool isVarArg) const {
+ if (getEffectiveCallingConv(CallConv, isVarArg) ==
+ CallingConv::ARM_AAPCS_VFP) {
+ HABaseType Base = HA_UNKNOWN;
+ uint64_t Members = 0;
+ bool result = isHomogeneousAggregate(Ty, Base, Members);
+ DEBUG(dbgs() << "isHA: " << result << " "; Ty->dump(); dbgs() << "\n");
+ return result;
+ } else {
+ return false;
+ }
+}