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-rw-r--r--contrib/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp94
1 files changed, 58 insertions, 36 deletions
diff --git a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
index 052c94e9d6a9..2d5aff28d27b 100644
--- a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
+++ b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
@@ -30,6 +30,7 @@
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfoImpls.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/MC/MCAsmInfo.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
@@ -42,8 +43,7 @@ using namespace llvm;
/// require stricter alignment than the stack pointer itself. Because we need
/// to shift the stack pointer by some unknown amount to force the alignment,
/// we need to record the value of the stack pointer on entry to the function.
-bool WebAssemblyFrameLowering::hasBP(
- const MachineFunction &MF) const {
+bool WebAssemblyFrameLowering::hasBP(const MachineFunction &MF) const {
const auto *RegInfo =
MF.getSubtarget<WebAssemblySubtarget>().getRegisterInfo();
return RegInfo->needsStackRealignment(MF);
@@ -78,36 +78,60 @@ bool WebAssemblyFrameLowering::hasReservedCallFrame(
return !MF.getFrameInfo().hasVarSizedObjects();
}
+// Returns true if this function needs a local user-space stack pointer for its
+// local frame (not for exception handling).
+bool WebAssemblyFrameLowering::needsSPForLocalFrame(
+ const MachineFunction &MF) const {
+ auto &MFI = MF.getFrameInfo();
+ return MFI.getStackSize() || MFI.adjustsStack() || hasFP(MF);
+}
+
+// In function with EH pads, we need to make a copy of the value of
+// __stack_pointer global in SP32 register, in order to use it when restoring
+// __stack_pointer after an exception is caught.
+bool WebAssemblyFrameLowering::needsPrologForEH(
+ const MachineFunction &MF) const {
+ auto EHType = MF.getTarget().getMCAsmInfo()->getExceptionHandlingType();
+ return EHType == ExceptionHandling::Wasm &&
+ MF.getFunction().hasPersonalityFn() && MF.getFrameInfo().hasCalls();
+}
/// Returns true if this function needs a local user-space stack pointer.
/// Unlike a machine stack pointer, the wasm user stack pointer is a global
/// variable, so it is loaded into a register in the prolog.
-bool WebAssemblyFrameLowering::needsSP(const MachineFunction &MF,
- const MachineFrameInfo &MFI) const {
- return MFI.getStackSize() || MFI.adjustsStack() || hasFP(MF);
+bool WebAssemblyFrameLowering::needsSP(const MachineFunction &MF) const {
+ return needsSPForLocalFrame(MF) || needsPrologForEH(MF);
}
/// Returns true if the local user-space stack pointer needs to be written back
-/// to memory by this function (this is not meaningful if needsSP is false). If
-/// false, the stack red zone can be used and only a local SP is needed.
+/// to __stack_pointer global by this function (this is not meaningful if
+/// needsSP is false). If false, the stack red zone can be used and only a local
+/// SP is needed.
bool WebAssemblyFrameLowering::needsSPWriteback(
- const MachineFunction &MF, const MachineFrameInfo &MFI) const {
- assert(needsSP(MF, MFI));
- return MFI.getStackSize() > RedZoneSize || MFI.hasCalls() ||
- MF.getFunction().hasFnAttribute(Attribute::NoRedZone);
+ const MachineFunction &MF) const {
+ auto &MFI = MF.getFrameInfo();
+ assert(needsSP(MF));
+ // When we don't need a local stack pointer for its local frame but only to
+ // support EH, we don't need to write SP back in the epilog, because we don't
+ // bump down the stack pointer in the prolog. We need to write SP back in the
+ // epilog only if
+ // 1. We need SP not only for EH support but also because we actually use
+ // stack or we have a frame address taken.
+ // 2. We cannot use the red zone.
+ bool CanUseRedZone = MFI.getStackSize() <= RedZoneSize && !MFI.hasCalls() &&
+ !MF.getFunction().hasFnAttribute(Attribute::NoRedZone);
+ return needsSPForLocalFrame(MF) && !CanUseRedZone;
}
-static void writeSPToMemory(unsigned SrcReg, MachineFunction &MF,
- MachineBasicBlock &MBB,
- MachineBasicBlock::iterator &InsertAddr,
- MachineBasicBlock::iterator &InsertStore,
- const DebugLoc &DL) {
+void WebAssemblyFrameLowering::writeSPToGlobal(
+ unsigned SrcReg, MachineFunction &MF, MachineBasicBlock &MBB,
+ MachineBasicBlock::iterator &InsertStore, const DebugLoc &DL) const {
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
const char *ES = "__stack_pointer";
auto *SPSymbol = MF.createExternalSymbolName(ES);
- BuildMI(MBB, InsertStore, DL, TII->get(WebAssembly::SET_GLOBAL_I32))
- .addExternalSymbol(SPSymbol)
+ BuildMI(MBB, InsertStore, DL, TII->get(WebAssembly::GLOBAL_SET_I32))
+ .addExternalSymbol(SPSymbol, WebAssemblyII::MO_SYMBOL_GLOBAL)
.addReg(SrcReg);
}
@@ -119,9 +143,9 @@ WebAssemblyFrameLowering::eliminateCallFramePseudoInstr(
"Call frame pseudos should only be used for dynamic stack adjustment");
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
if (I->getOpcode() == TII->getCallFrameDestroyOpcode() &&
- needsSPWriteback(MF, MF.getFrameInfo())) {
+ needsSPWriteback(MF)) {
DebugLoc DL = I->getDebugLoc();
- writeSPToMemory(WebAssembly::SP32, MF, MBB, I, I, DL);
+ writeSPToGlobal(WebAssembly::SP32, MF, MBB, I, DL);
}
return MBB.erase(I);
}
@@ -133,7 +157,8 @@ void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
assert(MFI.getCalleeSavedInfo().empty() &&
"WebAssembly should not have callee-saved registers");
- if (!needsSP(MF, MFI)) return;
+ if (!needsSP(MF))
+ return;
uint64_t StackSize = MFI.getStackSize();
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
@@ -152,8 +177,8 @@ void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
const char *ES = "__stack_pointer";
auto *SPSymbol = MF.createExternalSymbolName(ES);
- BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::GET_GLOBAL_I32), SPReg)
- .addExternalSymbol(SPSymbol);
+ BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::GLOBAL_GET_I32), SPReg)
+ .addExternalSymbol(SPSymbol, WebAssemblyII::MO_SYMBOL_GLOBAL);
bool HasBP = hasBP(MF);
if (HasBP) {
@@ -177,7 +202,7 @@ void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
unsigned BitmaskReg = MRI.createVirtualRegister(PtrRC);
unsigned Alignment = MFI.getMaxAlignment();
assert((1u << countTrailingZeros(Alignment)) == Alignment &&
- "Alignment must be a power of 2");
+ "Alignment must be a power of 2");
BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::CONST_I32), BitmaskReg)
.addImm((int)~(Alignment - 1));
BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::AND_I32),
@@ -189,20 +214,19 @@ void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
// Unlike most conventional targets (where FP points to the saved FP),
// FP points to the bottom of the fixed-size locals, so we can use positive
// offsets in load/store instructions.
- BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::COPY),
- WebAssembly::FP32)
+ BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::COPY), WebAssembly::FP32)
.addReg(WebAssembly::SP32);
}
- if (StackSize && needsSPWriteback(MF, MFI)) {
- writeSPToMemory(WebAssembly::SP32, MF, MBB, InsertPt, InsertPt, DL);
+ if (StackSize && needsSPWriteback(MF)) {
+ writeSPToGlobal(WebAssembly::SP32, MF, MBB, InsertPt, DL);
}
}
void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
MachineBasicBlock &MBB) const {
- auto &MFI = MF.getFrameInfo();
- uint64_t StackSize = MFI.getStackSize();
- if (!needsSP(MF, MFI) || !needsSPWriteback(MF, MFI)) return;
+ uint64_t StackSize = MF.getFrameInfo().getStackSize();
+ if (!needsSP(MF) || !needsSPWriteback(MF))
+ return;
const auto *TII = MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
auto &MRI = MF.getRegInfo();
auto InsertPt = MBB.getFirstTerminator();
@@ -214,7 +238,6 @@ void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
// Restore the stack pointer. If we had fixed-size locals, add the offset
// subtracted in the prolog.
unsigned SPReg = 0;
- MachineBasicBlock::iterator InsertAddr = InsertPt;
if (hasBP(MF)) {
auto FI = MF.getInfo<WebAssemblyFunctionInfo>();
SPReg = FI->getBasePointerVreg();
@@ -222,9 +245,8 @@ void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
const TargetRegisterClass *PtrRC =
MRI.getTargetRegisterInfo()->getPointerRegClass(MF);
unsigned OffsetReg = MRI.createVirtualRegister(PtrRC);
- InsertAddr =
- BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::CONST_I32), OffsetReg)
- .addImm(StackSize);
+ BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::CONST_I32), OffsetReg)
+ .addImm(StackSize);
// In the epilog we don't need to write the result back to the SP32 physreg
// because it won't be used again. We can use a stackified register instead.
SPReg = MRI.createVirtualRegister(PtrRC);
@@ -235,5 +257,5 @@ void WebAssemblyFrameLowering::emitEpilogue(MachineFunction &MF,
SPReg = hasFP(MF) ? WebAssembly::FP32 : WebAssembly::SP32;
}
- writeSPToMemory(SPReg, MF, MBB, InsertAddr, InsertPt, DL);
+ writeSPToGlobal(SPReg, MF, MBB, InsertPt, DL);
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-10-26 01:34:18 +0000