[llvm] r282442 - [WebAssembly] Use the frame pointer instead of the stack pointer
Derek Schuff via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 26 14:18:03 PDT 2016
Author: dschuff
Date: Mon Sep 26 16:18:03 2016
New Revision: 282442
URL: http://llvm.org/viewvc/llvm-project?rev=282442&view=rev
Log:
[WebAssembly] Use the frame pointer instead of the stack pointer
When we have dynamic allocas we have a frame pointer, and
when we're lowering frame indexes we should make sure we use it.
Patch by Jacob Gravelle
Differential Revision: https://reviews.llvm.org/D24889
Modified:
llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
llvm/trunk/test/CodeGen/WebAssembly/userstack.ll
Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp?rev=282442&r1=282441&r2=282442&view=diff
==============================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp (original)
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp Mon Sep 26 16:18:03 2016
@@ -64,6 +64,11 @@ void WebAssemblyRegisterInfo::eliminateF
const MachineFrameInfo &MFI = MF.getFrameInfo();
int64_t FrameOffset = MFI.getStackSize() + MFI.getObjectOffset(FrameIndex);
+ assert(MFI.getObjectSize(FrameIndex) != 0 &&
+ "We assume that variable-sized objects have already been lowered, "
+ "and don't use FrameIndex operands.");
+ unsigned FrameRegister = getFrameRegister(MF);
+
// If this is the address operand of a load or store, make it relative to SP
// and fold the frame offset directly in.
if (MI.mayLoadOrStore() && FIOperandNum == WebAssembly::MemOpAddressOperandNo) {
@@ -73,7 +78,7 @@ void WebAssemblyRegisterInfo::eliminateF
if (static_cast<uint64_t>(Offset) <= std::numeric_limits<uint32_t>::max()) {
MI.getOperand(FIOperandNum - 1).setImm(Offset);
MI.getOperand(FIOperandNum)
- .ChangeToRegister(WebAssembly::SP32, /*IsDef=*/false);
+ .ChangeToRegister(FrameRegister, /*IsDef=*/false);
return;
}
}
@@ -94,7 +99,7 @@ void WebAssemblyRegisterInfo::eliminateF
MachineOperand &ImmMO = Def->getOperand(1);
ImmMO.setImm(ImmMO.getImm() + uint32_t(FrameOffset));
MI.getOperand(FIOperandNum)
- .ChangeToRegister(WebAssembly::SP32, /*IsDef=*/false);
+ .ChangeToRegister(FrameRegister, /*IsDef=*/false);
return;
}
}
@@ -104,7 +109,7 @@ void WebAssemblyRegisterInfo::eliminateF
// Otherwise create an i32.add SP, offset and make it the operand.
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
- unsigned FIRegOperand = WebAssembly::SP32;
+ unsigned FIRegOperand = FrameRegister;
if (FrameOffset) {
// Create i32.add SP, offset and make it the operand.
const TargetRegisterClass *PtrRC =
@@ -116,7 +121,7 @@ void WebAssemblyRegisterInfo::eliminateF
FIRegOperand = MRI.createVirtualRegister(PtrRC);
BuildMI(MBB, *II, II->getDebugLoc(), TII->get(WebAssembly::ADD_I32),
FIRegOperand)
- .addReg(WebAssembly::SP32)
+ .addReg(FrameRegister)
.addReg(OffsetOp);
}
MI.getOperand(FIOperandNum).ChangeToRegister(FIRegOperand, /*IsDef=*/false);
Modified: llvm/trunk/test/CodeGen/WebAssembly/userstack.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/WebAssembly/userstack.ll?rev=282442&r1=282441&r2=282442&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/userstack.ll (original)
+++ llvm/trunk/test/CodeGen/WebAssembly/userstack.ll Mon Sep 26 16:18:03 2016
@@ -173,21 +173,62 @@ define void @dynamic_alloca_redzone(i32
; CHECK-LABEL: dynamic_static_alloca:
define void @dynamic_static_alloca(i32 %alloc) noredzone {
; Decrement SP in the prolog by the static amount and writeback to memory.
- ; CHECK: i32.const $push[[L11:.+]]=, 0{{$}}
- ; CHECK: i32.const $push[[L8:.+]]=, 0{{$}}
- ; CHECK-NEXT: i32.load $push[[L9:.+]]=, __stack_pointer($pop[[L8]])
- ; CHECK-NEXT: i32.const $push[[L10:.+]]=, 16
- ; CHECK-NEXT: i32.sub $push[[L20:.+]]=, $pop[[L9]], $pop[[L10]]
- ; CHECK-NEXT: tee_local $push[[L19:.+]]=, $[[FP:.+]]=, $pop[[L20]]
- ; CHECK: i32.store $drop=, __stack_pointer($pop{{.+}}), $pop{{.+}}
+ ; CHECK: i32.const $push[[L13:.+]]=, 0{{$}}
+ ; CHECK: i32.const $push[[L10:.+]]=, 0{{$}}
+ ; CHECK-NEXT: i32.load $push[[L11:.+]]=, __stack_pointer($pop[[L10]])
+ ; CHECK-NEXT: i32.const $push[[L12:.+]]=, 16
+ ; CHECK-NEXT: i32.sub $push[[L23:.+]]=, $pop[[L11]], $pop[[L12]]
+ ; CHECK-NEXT: tee_local $push[[L22:.+]]=, $[[SP:.+]]=, $pop[[L23]]
+ ; CHECK-NEXT: i32.store $drop=, __stack_pointer($pop{{.+}}), $pop[[L22]]
+
+ ; Alloc and write to a static alloca
+ ; CHECK: copy_local $push[[L21:.+]]=, $[[SP]]
+ ; CHECK-NEXT: tee_local $push[[pushedFP:.+]]=, $[[FP:.+]]=, $pop[[L21]]
+ ; CHECK-NEXT: i32.const $push[[L0:.+]]=, 101
+ ; CHECK-NEXT: i32.store $drop=, [[static_offset:.+]]($pop[[pushedFP]]), $pop[[L0]]
+ %static = alloca i32
+ store volatile i32 101, i32* %static
+
+ ; Decrement SP in the body by the dynamic amount.
+ ; CHECK: i32.sub
+ ; CHECK: tee_local $push{{.+}}=, $[[dynamic_local:.+]]=, $pop{{.+}}
+ ; CHECK: i32.store {{.*}} __stack_pointer
+ %dynamic = alloca i32, i32 %alloc
+
+ ; Ensure we don't modify the frame pointer after assigning it.
+ ; CHECK-NOT: $[[FP]]=
+
+ ; Ensure the static address doesn't change after modifying the stack pointer.
+ ; CHECK: i32.const $push[[L7:.+]]=, 102
+ ; CHECK-NEXT: i32.store $drop=, [[static_offset]]($[[FP]]), $pop[[L7]]
+ ; CHECK-NEXT: i32.const $push[[L8:.+]]=, 103
+ ; CHECK-NEXT: i32.store $drop=, 0($[[dynamic_local]]), $pop[[L8]]
+ store volatile i32 102, i32* %static
+ store volatile i32 103, i32* %dynamic
+
; Decrement SP in the body by the dynamic amount.
; CHECK: i32.sub
+ ; CHECK: tee_local $push{{.+}}=, $[[dynamic2_local:.+]]=, $pop{{.+}}
+ %dynamic.2 = alloca i32, i32 %alloc
+
+ ; CHECK-NOT: $[[FP]]=
+
+ ; Ensure neither the static nor dynamic address changes after the second
+ ; modification of the stack pointer.
+ ; CHECK: i32.const $push[[L9:.+]]=, 104
+ ; CHECK-NEXT: i32.store $drop=, [[static_offset]]($[[FP]]), $pop[[L9]]
+ ; CHECK-NEXT: i32.const $push[[L10:.+]]=, 105
+ ; CHECK-NEXT: i32.store $drop=, 0($[[dynamic_local]]), $pop[[L10]]
+ ; CHECK-NEXT: i32.const $push[[L11:.+]]=, 106
+ ; CHECK-NEXT: i32.store $drop=, 0($[[dynamic2_local]]), $pop[[L11]]
+ store volatile i32 104, i32* %static
+ store volatile i32 105, i32* %dynamic
+ store volatile i32 106, i32* %dynamic.2
+
; Writeback to memory.
- ; CHECK: i32.store $drop=, __stack_pointer($pop{{.+}}), $pop{{.+}}
- %r1 = alloca i32
- %r = alloca i32, i32 %alloc
- store i32 0, i32* %r
- ; CHEC: i32.store $drop=, 0($pop{{.+}}), $pop{{.+}}
+ ; CHECK: i32.const $push[[L17:.+]]=, 16
+ ; CHECK-NEXT: i32.add $push[[L18:.+]]=, $[[FP]], $pop[[L17]]
+ ; CHECK-NEXT: i32.store $drop=, __stack_pointer($pop{{.+}}), $pop[[L18]]
ret void
}
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