forked from OSchip/llvm-project
[bpf] error when BPF stack size exceeds 512 bytes
Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 292180
This commit is contained in:
Alexei Starovoitov
parent
36d382b773
commit
05de2e4818
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@ -21,6 +21,7 @@
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Target/TargetFrameLowering.h"
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#include "llvm/Target/TargetInstrInfo.h"
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#include "llvm/IR/DiagnosticInfo.h"
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#define GET_REGINFO_TARGET_DESC
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#include "BPFGenRegisterInfo.inc"
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@ -41,6 +42,18 @@ BitVector BPFRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
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return Reserved;
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}
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static void WarnSize(int Offset, MachineFunction &MF, DebugLoc& DL)
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{
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if (Offset <= -512) {
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auto F = MF.getFunction();
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DiagnosticInfoUnsupported DiagStackSize(*F,
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"Looks like the BPF stack limit of 512 bytes is exceeded. "
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"Please move large on stack variables into BPF per-cpu array map.\n",
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DL);
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F->getContext().diagnose(DiagStackSize);
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}
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}
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void BPFRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
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int SPAdj, unsigned FIOperandNum,
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RegScavenger *RS) const {
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@ -48,9 +61,18 @@ void BPFRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
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unsigned i = 0;
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MachineInstr &MI = *II;
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MachineFunction &MF = *MI.getParent()->getParent();
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MachineBasicBlock &MBB = *MI.getParent();
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MachineFunction &MF = *MBB.getParent();
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DebugLoc DL = MI.getDebugLoc();
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if (!DL)
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/* try harder to get some debug loc */
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for (auto &I : MBB)
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if (I.getDebugLoc()) {
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DL = I.getDebugLoc();
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break;
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}
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while (!MI.getOperand(i).isFI()) {
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++i;
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assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
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@ -59,11 +81,11 @@ void BPFRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
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unsigned FrameReg = getFrameRegister(MF);
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int FrameIndex = MI.getOperand(i).getIndex();
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const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
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MachineBasicBlock &MBB = *MI.getParent();
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if (MI.getOpcode() == BPF::MOV_rr) {
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int Offset = MF.getFrameInfo().getObjectOffset(FrameIndex);
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WarnSize(Offset, MF, DL);
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MI.getOperand(i).ChangeToRegister(FrameReg, false);
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unsigned reg = MI.getOperand(i - 1).getReg();
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BuildMI(MBB, ++II, DL, TII.get(BPF::ADD_ri), reg)
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@ -78,6 +100,8 @@ void BPFRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
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if (!isInt<32>(Offset))
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llvm_unreachable("bug in frame offset");
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WarnSize(Offset, MF, DL);
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if (MI.getOpcode() == BPF::FI_ri) {
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// architecture does not really support FI_ri, replace it with
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// MOV_rr <target_reg>, frame_reg
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@ -0,0 +1,76 @@
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; RUN: not llc -march=bpfel < %s 2>&1 >/dev/null | FileCheck %s
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;; CHECK-NOT: nowarn
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define void @nowarn() local_unnamed_addr #0 !dbg !6 {
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%1 = alloca [504 x i8], align 1
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%2 = getelementptr inbounds [504 x i8], [504 x i8]* %1, i64 0, i64 0, !dbg !15
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call void @llvm.lifetime.start(i64 504, i8* nonnull %2) #4, !dbg !15
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tail call void @llvm.dbg.declare(metadata [504 x i8]* %1, metadata !10, metadata !16), !dbg !17
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call void @doit(i8* nonnull %2) #4, !dbg !18
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call void @llvm.lifetime.end(i64 504, i8* nonnull %2) #4, !dbg !19
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ret void, !dbg !19
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}
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.start(i64, i8* nocapture) #1
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; Function Attrs: nounwind readnone
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #2
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declare void @doit(i8*) local_unnamed_addr #3
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; Function Attrs: argmemonly nounwind
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declare void @llvm.lifetime.end(i64, i8* nocapture) #1
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; CHECK: error: warn_stack.c
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; CHECK: BPF stack limit
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define void @warn() local_unnamed_addr #0 !dbg !20 {
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%1 = alloca [512 x i8], align 1
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%2 = getelementptr inbounds [512 x i8], [512 x i8]* %1, i64 0, i64 0, !dbg !26
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call void @llvm.lifetime.start(i64 512, i8* nonnull %2) #4, !dbg !26
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tail call void @llvm.dbg.declare(metadata [512 x i8]* %1, metadata !22, metadata !16), !dbg !27
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call void @doit(i8* nonnull %2) #4, !dbg !28
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call void @llvm.lifetime.end(i64 512, i8* nonnull %2) #4, !dbg !29
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ret void, !dbg !29
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}
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attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #1 = { argmemonly nounwind }
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attributes #2 = { nounwind readnone }
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attributes #3 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
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attributes #4 = { nounwind }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4}
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!llvm.ident = !{!5}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 5.0.0 (trunk 292141) (llvm/trunk 292156)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "warn_stack.c", directory: "/w/llvm/bld")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{!"clang version 5.0.0 (trunk 292141) (llvm/trunk 292156)"}
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!6 = distinct !DISubprogram(name: "nowarn", scope: !1, file: !1, line: 2, type: !7, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !9)
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!7 = !DISubroutineType(types: !8)
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!8 = !{null}
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!9 = !{!10}
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!10 = !DILocalVariable(name: "buf", scope: !6, file: !1, line: 4, type: !11)
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!11 = !DICompositeType(tag: DW_TAG_array_type, baseType: !12, size: 4088, elements: !13)
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!12 = !DIBasicType(name: "char", size: 8, encoding: DW_ATE_signed_char)
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!13 = !{!14}
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!14 = !DISubrange(count: 504)
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!15 = !DILocation(line: 4, column: 2, scope: !6)
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!16 = !DIExpression()
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!17 = !DILocation(line: 4, column: 7, scope: !6)
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!18 = !DILocation(line: 5, column: 2, scope: !6)
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!19 = !DILocation(line: 6, column: 1, scope: !6)
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!20 = distinct !DISubprogram(name: "warn", scope: !1, file: !1, line: 7, type: !7, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !21)
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!21 = !{!22}
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!22 = !DILocalVariable(name: "buf", scope: !20, file: !1, line: 9, type: !23)
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!23 = !DICompositeType(tag: DW_TAG_array_type, baseType: !12, size: 4096, elements: !24)
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!24 = !{!25}
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!25 = !DISubrange(count: 512)
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!26 = !DILocation(line: 9, column: 2, scope: !20)
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!27 = !DILocation(line: 9, column: 7, scope: !20)
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!28 = !DILocation(line: 10, column: 2, scope: !20)
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!29 = !DILocation(line: 11, column: 1, scope: !20)
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