[AArch64] Implement GHC calling convention

Original patch by Luke Iannini.  Minor improvements and test added by
Erik de Castro Lopo.

Differential Revision: http://reviews.llvm.org/D6877

From: Erik de Castro Lopo <erikd@mega-nerd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226473 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Greg Fitzgerald 2015-01-19 17:40:05 +00:00
parent 438f1e4979
commit 4b96323e81
6 changed files with 151 additions and 1 deletions

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@ -204,6 +204,44 @@ def RetCC_AArch64_WebKit_JS : CallingConv<[
[Q0, Q1, Q2, Q3, Q4, Q5, Q6, Q7]>>
]>;
//===----------------------------------------------------------------------===//
// ARM64 Calling Convention for GHC
//===----------------------------------------------------------------------===//
// This calling convention is specific to the Glasgow Haskell Compiler.
// The only documentation is the GHC source code, specifically the C header
// file:
//
// https://github.com/ghc/ghc/blob/master/includes/stg/MachRegs.h
//
// which defines the registers for the Spineless Tagless G-Machine (STG) that
// GHC uses to implement lazy evaluation. The generic STG machine has a set of
// registers which are mapped to appropriate set of architecture specific
// registers for each CPU architecture.
//
// The STG Machine is documented here:
//
// https://ghc.haskell.org/trac/ghc/wiki/Commentary/Compiler/GeneratedCode
//
// The AArch64 register mapping is under the heading "The ARMv8/AArch64 ABI
// register mapping".
def CC_AArch64_GHC : CallingConv<[
// Handle all vector types as either f64 or v2f64.
CCIfType<[v1i64, v2i32, v4i16, v8i8, v2f32], CCBitConvertToType<f64>>,
CCIfType<[v2i64, v4i32, v8i16, v16i8, v4f32, f128], CCBitConvertToType<v2f64>>,
CCIfType<[v2f64], CCAssignToReg<[Q4, Q5]>>,
CCIfType<[f32], CCAssignToReg<[S8, S9, S10, S11]>>,
CCIfType<[f64], CCAssignToReg<[D12, D13, D14, D15]>>,
// Promote i8/i16/i32 arguments to i64.
CCIfType<[i8, i16, i32], CCPromoteToType<i64>>,
// Pass in STG registers: Base, Sp, Hp, R1, R2, R3, R4, R5, R6, SpLim
CCIfType<[i64], CCAssignToReg<[X19, X20, X21, X22, X23, X24, X25, X26, X27, X28]>>
]>;
// FIXME: LR is only callee-saved in the sense that *we* preserve it and are
// presumably a callee to someone. External functions may not do so, but this
// is currently safe since BL has LR as an implicit-def and what happens after a
@ -249,3 +287,4 @@ def CSR_AArch64_AllRegs
(sequence "S%u", 0, 31), (sequence "D%u", 0, 31),
(sequence "Q%u", 0, 31))>;
def CSR_AArch64_NoRegs : CalleeSavedRegs<(add)>;

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@ -302,6 +302,8 @@ static unsigned getImplicitScaleFactor(MVT VT) {
CCAssignFn *AArch64FastISel::CCAssignFnForCall(CallingConv::ID CC) const {
if (CC == CallingConv::WebKit_JS)
return CC_AArch64_WebKit_JS;
if (CC == CallingConv::GHC)
return CC_AArch64_GHC;
return Subtarget->isTargetDarwin() ? CC_AArch64_DarwinPCS : CC_AArch64_AAPCS;
}

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@ -215,6 +215,11 @@ void AArch64FrameLowering::emitPrologue(MachineFunction &MF) const {
bool HasFP = hasFP(MF);
DebugLoc DL = MBB.findDebugLoc(MBBI);
// All calls are tail calls in GHC calling conv, and functions have no
// prologue/epilogue.
if (MF.getFunction()->getCallingConv() == CallingConv::GHC)
return;
int NumBytes = (int)MFI->getStackSize();
if (!AFI->hasStackFrame()) {
assert(!HasFP && "unexpected function without stack frame but with FP");
@ -451,6 +456,11 @@ void AArch64FrameLowering::emitEpilogue(MachineFunction &MF,
int NumBytes = MFI->getStackSize();
const AArch64FunctionInfo *AFI = MF.getInfo<AArch64FunctionInfo>();
// All calls are tail calls in GHC calling conv, and functions have no
// prologue/epilogue.
if (MF.getFunction()->getCallingConv() == CallingConv::GHC)
return;
// Initial and residual are named for consitency with the prologue. Note that
// in the epilogue, the residual adjustment is executed first.
uint64_t ArgumentPopSize = 0;

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@ -1990,6 +1990,8 @@ CCAssignFn *AArch64TargetLowering::CCAssignFnForCall(CallingConv::ID CC,
llvm_unreachable("Unsupported calling convention.");
case CallingConv::WebKit_JS:
return CC_AArch64_WebKit_JS;
case CallingConv::GHC:
return CC_AArch64_GHC;
case CallingConv::C:
case CallingConv::Fast:
if (!Subtarget->isTargetDarwin())

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@ -40,6 +40,10 @@ AArch64RegisterInfo::AArch64RegisterInfo(const AArch64InstrInfo *tii,
const MCPhysReg *
AArch64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
assert(MF && "Invalid MachineFunction pointer.");
if (MF->getFunction()->getCallingConv() == CallingConv::GHC)
// GHC set of callee saved regs is empty as all those regs are
// used for passing STG regs around
return CSR_AArch64_NoRegs_SaveList;
if (MF->getFunction()->getCallingConv() == CallingConv::AnyReg)
return CSR_AArch64_AllRegs_SaveList;
else
@ -48,6 +52,9 @@ AArch64RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
const uint32_t *
AArch64RegisterInfo::getCallPreservedMask(CallingConv::ID CC) const {
if (CC == CallingConv::GHC)
// This is academic becase all GHC calls are (supposed to be) tail calls
return CSR_AArch64_NoRegs_RegMask;
if (CC == CallingConv::AnyReg)
return CSR_AArch64_AllRegs_RegMask;
else
@ -63,7 +70,7 @@ const uint32_t *AArch64RegisterInfo::getTLSCallPreservedMask() const {
}
const uint32_t *
AArch64RegisterInfo::getThisReturnPreservedMask(CallingConv::ID) const {
AArch64RegisterInfo::getThisReturnPreservedMask(CallingConv::ID CC) const {
// This should return a register mask that is the same as that returned by
// getCallPreservedMask but that additionally preserves the register used for
// the first i64 argument (which must also be the register used to return a
@ -71,6 +78,7 @@ AArch64RegisterInfo::getThisReturnPreservedMask(CallingConv::ID) const {
//
// In case that the calling convention does not use the same register for
// both, the function should return NULL (does not currently apply)
assert(CC != CallingConv::GHC && "should not be GHC calling convention.");
return CSR_AArch64_AAPCS_ThisReturn_RegMask;
}

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@ -0,0 +1,89 @@
; RUN: llc -mtriple=aarch64-unknown-linux-gnu < %s | FileCheck %s
; Check the GHC call convention works (aarch64)
@base = external global i64 ; assigned to register: r19
@sp = external global i64 ; assigned to register: r20
@hp = external global i64 ; assigned to register: r21
@r1 = external global i64 ; assigned to register: r22
@r2 = external global i64 ; assigned to register: r23
@r3 = external global i64 ; assigned to register: r24
@r4 = external global i64 ; assigned to register: r25
@r5 = external global i64 ; assigned to register: r26
@r6 = external global i64 ; assigned to register: r27
@splim = external global i64 ; assigned to register: r28
@f1 = external global float ; assigned to register: s8
@f2 = external global float ; assigned to register: s9
@f3 = external global float ; assigned to register: s10
@f4 = external global float ; assigned to register: s11
@d1 = external global double ; assigned to register: d12
@d2 = external global double ; assigned to register: d13
@d3 = external global double ; assigned to register: d14
@d4 = external global double ; assigned to register: d15
define ghccc i64 @addtwo(i64 %x, i64 %y) nounwind {
entry:
; CHECK-LABEL: addtwo
; CHECK: add x0, x19, x20
; CHECK-NEXT: ret
%0 = add i64 %x, %y
ret i64 %0
}
define void @zap(i64 %a, i64 %b) nounwind {
entry:
; CHECK-LABEL: zap
; CHECK-NOT: mov {{x[0-9]+}}, sp
; CHECK: bl addtwo
; CHECK-NEXT: bl foo
%0 = call ghccc i64 @addtwo(i64 %a, i64 %b)
call void @foo() nounwind
ret void
}
define ghccc void @foo_i64 () nounwind {
entry:
; CHECK-LABEL: foo_i64
; CHECK: adrp {{x[0-9]+}}, base
; CHECK-NEXT: ldr x19, [{{x[0-9]+}}, :lo12:base]
; CHECK-NEXT: bl bar_i64
; CHECK-NEXT: ret
%0 = load i64* @base
tail call ghccc void @bar_i64( i64 %0 ) nounwind
ret void
}
define ghccc void @foo_float () nounwind {
entry:
; CHECK-LABEL: foo_float
; CHECK: adrp {{x[0-9]+}}, f1
; CHECK-NEXT: ldr s8, [{{x[0-9]+}}, :lo12:f1]
; CHECK-NEXT: bl bar_float
; CHECK-NEXT: ret
%0 = load float* @f1
tail call ghccc void @bar_float( float %0 ) nounwind
ret void
}
define ghccc void @foo_double () nounwind {
entry:
; CHECK-LABEL: foo_double
; CHECK: adrp {{x[0-9]+}}, d1
; CHECK-NEXT: ldr d12, [{{x[0-9]+}}, :lo12:d1]
; CHECK-NEXT: bl bar_double
; CHECK-NEXT: ret
%0 = load double* @d1
tail call ghccc void @bar_double( double %0 ) nounwind
ret void
}
declare ghccc void @foo ()
declare ghccc void @bar_i64 (i64)
declare ghccc void @bar_float (float)
declare ghccc void @bar_double (double)