[llvm] r252318 - [WinEH] Mark funclet entries and exits as clobbering all registers
Reid Kleckner via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 6 09:06:39 PST 2015
Author: rnk
Date: Fri Nov 6 11:06:38 2015
New Revision: 252318
URL: http://llvm.org/viewvc/llvm-project?rev=252318&view=rev
Log:
[WinEH] Mark funclet entries and exits as clobbering all registers
Summary:
In this implementation, LiveIntervalAnalysis invents a few register
masks on basic block boundaries that preserve no registers. The nice
thing about this is that it prevents the prologue inserter from thinking
it needs to spill all XMM CSRs, because it doesn't see any explicit
physreg defs in the MI.
Reviewers: MatzeB, qcolombet, JosephTremoulet, majnemer
Subscribers: MatzeB, llvm-commits
Differential Revision: http://reviews.llvm.org/D14407
Added:
llvm/trunk/test/CodeGen/X86/catchpad-regmask.ll
llvm/trunk/test/CodeGen/X86/cleanuppad-large-codemodel.ll
Modified:
llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.h
llvm/trunk/lib/Target/X86/X86RegisterInfo.h
Modified: llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h (original)
+++ llvm/trunk/include/llvm/CodeGen/MachineBasicBlock.h Fri Nov 6 11:06:38 2015
@@ -376,6 +376,14 @@ public:
return make_range(livein_begin(), livein_end());
}
+ /// Get the clobber mask for the start of this basic block. Funclets use this
+ /// to prevent register allocation across funclet transitions.
+ const uint32_t *getBeginClobberMask(const TargetRegisterInfo *TRI) const;
+
+ /// Get the clobber mask for the end of the basic block.
+ /// \see getBeginClobberMask()
+ const uint32_t *getEndClobberMask(const TargetRegisterInfo *TRI) const;
+
/// Return alignment of the basic block. The alignment is specified as
/// log2(bytes).
unsigned getAlignment() const { return Alignment; }
@@ -548,8 +556,8 @@ public:
return const_cast<MachineBasicBlock *>(this)->getLastNonDebugInstr();
}
- /// Convenience function that returns true if the block has no successors and
- /// contains a return instruction.
+ /// Convenience function that returns true if the block ends in a return
+ /// instruction.
bool isReturnBlock() const {
return !empty() && back().isReturn();
}
Modified: llvm/trunk/include/llvm/Target/TargetRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetRegisterInfo.h?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetRegisterInfo.h (original)
+++ llvm/trunk/include/llvm/Target/TargetRegisterInfo.h Fri Nov 6 11:06:38 2015
@@ -475,6 +475,11 @@ public:
return nullptr;
}
+ /// Return a register mask that clobbers everything.
+ virtual const uint32_t *getNoPreservedMask() const {
+ llvm_unreachable("target does not provide no presered mask");
+ }
+
/// Return all the call-preserved register masks defined for this target.
virtual ArrayRef<const uint32_t *> getRegMasks() const = 0;
virtual ArrayRef<const char *> getRegMaskNames() const = 0;
Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Fri Nov 6 11:06:38 2015
@@ -225,6 +225,13 @@ void LiveIntervals::computeRegMasks() {
for (MachineBasicBlock &MBB : *MF) {
std::pair<unsigned, unsigned> &RMB = RegMaskBlocks[MBB.getNumber()];
RMB.first = RegMaskSlots.size();
+
+ // Some block starts, such as EH funclets, create masks.
+ if (const uint32_t *Mask = MBB.getBeginClobberMask(TRI)) {
+ RegMaskSlots.push_back(Indexes->getMBBStartIdx(&MBB));
+ RegMaskBits.push_back(Mask);
+ }
+
for (MachineInstr &MI : MBB) {
for (const MachineOperand &MO : MI.operands()) {
if (!MO.isRegMask())
@@ -233,6 +240,13 @@ void LiveIntervals::computeRegMasks() {
RegMaskBits.push_back(MO.getRegMask());
}
}
+
+ // Some block ends, such as funclet returns, create masks.
+ if (const uint32_t *Mask = MBB.getEndClobberMask(TRI)) {
+ RegMaskSlots.push_back(Indexes->getMBBEndIdx(&MBB));
+ RegMaskBits.push_back(Mask);
+ }
+
// Compute the number of register mask instructions in this block.
RMB.second = RegMaskSlots.size() - RMB.first;
}
Modified: llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp (original)
+++ llvm/trunk/lib/CodeGen/MachineBasicBlock.cpp Fri Nov 6 11:06:38 2015
@@ -1301,3 +1301,17 @@ MachineBasicBlock::computeRegisterLivene
// At this point we have no idea of the liveness of the register.
return LQR_Unknown;
}
+
+const uint32_t *
+MachineBasicBlock::getBeginClobberMask(const TargetRegisterInfo *TRI) const {
+ // EH funclet entry does not preserve any registers.
+ return isEHFuncletEntry() ? TRI->getNoPreservedMask() : nullptr;
+}
+
+const uint32_t *
+MachineBasicBlock::getEndClobberMask(const TargetRegisterInfo *TRI) const {
+ // If we see a return block with successors, this must be a funclet return,
+ // which does not preserve any registers. If there are no successors, we don't
+ // care what kind of return it is, putting a mask after it is a no-op.
+ return isReturnBlock() && !succ_empty() ? TRI->getNoPreservedMask() : nullptr;
+}
Modified: llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMBaseRegisterInfo.h Fri Nov 6 11:06:38 2015
@@ -94,7 +94,7 @@ public:
const MCPhysReg *getCalleeSavedRegs(const MachineFunction *MF) const override;
const uint32_t *getCallPreservedMask(const MachineFunction &MF,
CallingConv::ID) const override;
- const uint32_t *getNoPreservedMask() const;
+ const uint32_t *getNoPreservedMask() const override;
/// getThisReturnPreservedMask - Returns a call preserved mask specific to the
/// case that 'returned' is on an i32 first argument if the calling convention
Modified: llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.h?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.h (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCRegisterInfo.h Fri Nov 6 11:06:38 2015
@@ -77,7 +77,7 @@ public:
const MCPhysReg *getCalleeSavedRegs(const MachineFunction *MF) const override;
const uint32_t *getCallPreservedMask(const MachineFunction &MF,
CallingConv::ID CC) const override;
- const uint32_t *getNoPreservedMask() const;
+ const uint32_t *getNoPreservedMask() const override;
void adjustStackMapLiveOutMask(uint32_t *Mask) const override;
Modified: llvm/trunk/lib/Target/X86/X86RegisterInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86RegisterInfo.h?rev=252318&r1=252317&r2=252318&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86RegisterInfo.h (original)
+++ llvm/trunk/lib/Target/X86/X86RegisterInfo.h Fri Nov 6 11:06:38 2015
@@ -96,7 +96,7 @@ public:
getCalleeSavedRegs(const MachineFunction* MF) const override;
const uint32_t *getCallPreservedMask(const MachineFunction &MF,
CallingConv::ID) const override;
- const uint32_t *getNoPreservedMask() const;
+ const uint32_t *getNoPreservedMask() const override;
/// getReservedRegs - Returns a bitset indexed by physical register number
/// indicating if a register is a special register that has particular uses and
Added: llvm/trunk/test/CodeGen/X86/catchpad-regmask.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/catchpad-regmask.ll?rev=252318&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/catchpad-regmask.ll (added)
+++ llvm/trunk/test/CodeGen/X86/catchpad-regmask.ll Fri Nov 6 11:06:38 2015
@@ -0,0 +1,150 @@
+; RUN: llc < %s | FileCheck %s
+
+; Based on this code:
+;
+; extern "C" int array[4];
+; extern "C" void global_array(int idx1, int idx2, int idx3) {
+; try {
+; array[idx1] = 111;
+; throw;
+; } catch (...) {
+; array[idx2] = 222;
+; }
+; array[idx3] = 333;
+; }
+; extern "C" __declspec(dllimport) int imported;
+; extern "C" void access_imported() {
+; try {
+; imported = 111;
+; throw;
+; } catch (...) {
+; imported = 222;
+; }
+; imported = 333;
+; }
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc18.0.0"
+
+%eh.ThrowInfo = type { i32, i32, i32, i32 }
+
+ at array = external global [4 x i32], align 16
+ at imported = external dllimport global i32, align 4
+
+; Function Attrs: uwtable
+define void @global_array(i32 %idx1, i32 %idx2, i32 %idx3) #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+ %idxprom = sext i32 %idx1 to i64
+ %arrayidx = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom
+ store i32 111, i32* %arrayidx, align 4, !tbaa !2
+ invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
+ to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch: ; preds = %entry
+ %0 = catchpad [i8* null, i32 64, i8* null]
+ to label %catch unwind label %catchendblock
+
+catch: ; preds = %catch.dispatch
+ %idxprom1 = sext i32 %idx2 to i64
+ %arrayidx2 = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom1
+ store i32 222, i32* %arrayidx2, align 4, !tbaa !2
+ catchret %0 to label %try.cont
+
+try.cont: ; preds = %catch
+ %idxprom3 = sext i32 %idx3 to i64
+ %arrayidx4 = getelementptr inbounds [4 x i32], [4 x i32]* @array, i64 0, i64 %idxprom3
+ store i32 333, i32* %arrayidx4, align 4, !tbaa !2
+ ret void
+
+catchendblock: ; preds = %catch.dispatch
+ catchendpad unwind to caller
+
+unreachable: ; preds = %entry
+ unreachable
+}
+
+; CHECK-LABEL: global_array: # @global_array
+; CHECK: pushq %rbp
+; First array access
+; CHECK: movslq %ecx, %[[idx:[^ ]*]]
+; CHECK: leaq array(%rip), %[[base:[^ ]*]]
+; CHECK: movl $111, (%[[base]],%[[idx]],4)
+; Might throw an exception and return to below...
+; CHECK: callq _CxxThrowException
+; Third array access must remat the address of array
+; CHECK: movslq {{.*}}, %[[idx:[^ ]*]]
+; CHECK: leaq array(%rip), %[[base:[^ ]*]]
+; CHECK: movl $333, (%[[base]],%[[idx]],4)
+; CHECK: popq %rbp
+; CHECK: retq
+
+; CHECK: "?catch$2@?0?global_array at 4HA":
+; CHECK: pushq %rbp
+; CHECK: movslq {{.*}}, %[[idx:[^ ]*]]
+; CHECK: leaq array(%rip), %[[base:[^ ]*]]
+; CHECK: movl $222, (%[[base]],%[[idx]],4)
+; CHECK: popq %rbp
+; CHECK: retq # CATCHRET
+
+declare void @_CxxThrowException(i8*, %eh.ThrowInfo*)
+
+declare i32 @__CxxFrameHandler3(...)
+
+; Function Attrs: uwtable
+define void @access_imported() #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+entry:
+ store i32 111, i32* @imported, align 4, !tbaa !2
+ invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
+ to label %unreachable unwind label %catch.dispatch
+
+catch.dispatch: ; preds = %entry
+ %0 = catchpad [i8* null, i32 64, i8* null]
+ to label %catch unwind label %catchendblock
+
+catch: ; preds = %catch.dispatch
+ store i32 222, i32* @imported, align 4, !tbaa !2
+ catchret %0 to label %try.cont
+
+try.cont: ; preds = %catch
+ store i32 333, i32* @imported, align 4, !tbaa !2
+ ret void
+
+catchendblock: ; preds = %catch.dispatch
+ catchendpad unwind to caller
+
+unreachable: ; preds = %entry
+ unreachable
+}
+
+; CHECK-LABEL: access_imported: # @access_imported
+; CHECK: pushq %rbp
+; CHECK: movq __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl $111, (%[[base]])
+; Might throw an exception and return to below...
+; CHECK: callq _CxxThrowException
+; Third access must reload the address of imported
+; CHECK: movq __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl $333, (%[[base]])
+; CHECK: popq %rbp
+; CHECK: retq
+
+; CHECK: "?catch$2@?0?access_imported at 4HA":
+; CHECK: pushq %rbp
+; CHECK: movq __imp_imported(%rip), %[[base:[^ ]*]]
+; CHECK: movl $222, (%[[base]])
+; CHECK: popq %rbp
+; CHECK: retq # CATCHRET
+
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { noreturn }
+
+!llvm.module.flags = !{!0}
+!llvm.ident = !{!1}
+
+!0 = !{i32 1, !"PIC Level", i32 2}
+!1 = !{!"clang version 3.8.0 "}
+!2 = !{!3, !3, i64 0}
+!3 = !{!"int", !4, i64 0}
+!4 = !{!"omnipotent char", !5, i64 0}
+!5 = !{!"Simple C/C++ TBAA"}
Added: llvm/trunk/test/CodeGen/X86/cleanuppad-large-codemodel.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/cleanuppad-large-codemodel.ll?rev=252318&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/cleanuppad-large-codemodel.ll (added)
+++ llvm/trunk/test/CodeGen/X86/cleanuppad-large-codemodel.ll Fri Nov 6 11:06:38 2015
@@ -0,0 +1,27 @@
+; RUN: llc -mtriple=x86_64-pc-windows-msvc -code-model=large -o - < %s | FileCheck %s
+
+declare i32 @__CxxFrameHandler3(...)
+
+declare void @bar()
+
+define void @foo() personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+ invoke void @bar()
+ to label %exit unwind label %cleanup
+cleanup:
+ %c = cleanuppad []
+ call void @bar()
+ cleanupret %c unwind to caller
+exit:
+ ret void
+}
+
+; CHECK: foo: # @foo
+; CHECK: movabsq $bar, %[[reg:[^ ]*]]
+; CHECK: callq *%[[reg]]
+; CHECK: retq
+
+; CHECK: "?dtor$2@?0?foo at 4HA":
+; CHECK: movabsq $bar, %[[reg:[^ ]*]]
+; CHECK: callq *%[[reg]]
+; CHECK: retq # CLEANUPRET
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