[bpf] error when unknown bpf helper is called

Emit error when BPF backend sees a call to a global function or to an external symbol.
The kernel verifier only allows calls to predefined helpers from bpf.h
which are defined in 'enum bpf_func_id'. Such calls in assembler must
look like 'call [1-9]+' where number matches bpf_func_id.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292204 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/BPF/BPFISelLowering.cpp b/lib/Target/BPF/BPFISelLowering.cpp
index cca3492a1992a55c5755df590bfc2824bea42a2a..b222022f0658632023d059a7b5b295332c224274 100644 (file)
--- a/lib/Target/BPF/BPFISelLowering.cpp
+++ b/lib/Target/BPF/BPFISelLowering.cpp
@@ -33,7 +33,7 @@ using namespace llvm;
 
 #define DEBUG_TYPE "bpf-lower"
 
-static void fail(const SDLoc &DL, SelectionDAG &DAG, const char *Msg) {
+static void fail(const SDLoc &DL, SelectionDAG &DAG, const Twine &Msg) {
   MachineFunction &MF = DAG.getMachineFunction();
   DAG.getContext()->diagnose(
       DiagnosticInfoUnsupported(*MF.getFunction(), Msg, DL.getDebugLoc()));
@@ -306,11 +306,23 @@ SDValue BPFTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   // If the callee is a GlobalAddress node (quite common, every direct call is)
   // turn it into a TargetGlobalAddress node so that legalize doesn't hack it.
   // Likewise ExternalSymbol -> TargetExternalSymbol.
-  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
+  if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee)) {
+    auto GV = G->getGlobal();
+    Twine Msg("A call to global function '" + StringRef(GV->getName())
+               + "' is not supported. "
+               + (GV->isDeclaration() ?
+                 "Only calls to predefined BPF helpers are allowed." :
+                 "Please use __attribute__((always_inline) to make sure"
+                 " this function is inlined."));
+    fail(CLI.DL, DAG, Msg);
     Callee = DAG.getTargetGlobalAddress(G->getGlobal(), CLI.DL, PtrVT,
                                         G->getOffset(), 0);
-  else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee))
+  } else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee)) {
     Callee = DAG.getTargetExternalSymbol(E->getSymbol(), PtrVT, 0);
+    fail(CLI.DL, DAG, Twine("A call to built-in function '"
+                            + StringRef(E->getSymbol())
+                            + "' is not supported."));
+  }
 
   // Returns a chain & a flag for retval copy to use.
   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);

diff --git a/lib/Target/BPF/BPFInstrInfo.td b/lib/Target/BPF/BPFInstrInfo.td
index a7910dea98dee7290a27f48319c8755a9d5319e7..93ee24371c4d92bd077f305ba548e89a6d57c7f9 100644 (file)
--- a/lib/Target/BPF/BPFInstrInfo.td
+++ b/lib/Target/BPF/BPFInstrInfo.td
@@ -470,6 +470,7 @@ def : Pat<(i64 (and (i64 GPR:$src), 0xffffFFFF)),
 
 // Calls
 def : Pat<(BPFcall tglobaladdr:$dst), (JAL tglobaladdr:$dst)>;
+def : Pat<(BPFcall texternalsym:$dst), (JAL texternalsym:$dst)>;
 def : Pat<(BPFcall imm:$dst), (JAL imm:$dst)>;
 
 // Loads

diff --git a/lib/Target/BPF/BPFMCInstLower.cpp b/lib/Target/BPF/BPFMCInstLower.cpp
index f64defecf3cc9b9bc85509f3dfecabb65dfd3529..1faa1c097656846a8301f8ef9c519c60629cd110 100644 (file)
--- a/lib/Target/BPF/BPFMCInstLower.cpp
+++ b/lib/Target/BPF/BPFMCInstLower.cpp
@@ -29,6 +29,11 @@ BPFMCInstLower::GetGlobalAddressSymbol(const MachineOperand &MO) const {
   return Printer.getSymbol(MO.getGlobal());
 }
 
+MCSymbol *
+BPFMCInstLower::GetExternalSymbolSymbol(const MachineOperand &MO) const {
+  return Printer.GetExternalSymbolSymbol(MO.getSymbolName());
+}
+
 MCOperand BPFMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
                                              MCSymbol *Sym) const {
 
@@ -66,6 +71,9 @@ void BPFMCInstLower::Lower(const MachineInstr *MI, MCInst &OutMI) const {
       break;
     case MachineOperand::MO_RegisterMask:
       continue;
+    case MachineOperand::MO_ExternalSymbol:
+      MCOp = LowerSymbolOperand(MO, GetExternalSymbolSymbol(MO));
+      break;
     case MachineOperand::MO_GlobalAddress:
       MCOp = LowerSymbolOperand(MO, GetGlobalAddressSymbol(MO));
       break;

diff --git a/lib/Target/BPF/BPFMCInstLower.h b/lib/Target/BPF/BPFMCInstLower.h
index 054e89407db281db82c3178c22a875e346673c10..eac811f4cf8821ed41c59e9cc24616537fb6a392 100644 (file)
--- a/lib/Target/BPF/BPFMCInstLower.h
+++ b/lib/Target/BPF/BPFMCInstLower.h
@@ -37,6 +37,7 @@ public:
   MCOperand LowerSymbolOperand(const MachineOperand &MO, MCSymbol *Sym) const;
 
   MCSymbol *GetGlobalAddressSymbol(const MachineOperand &MO) const;
+  MCSymbol *GetExternalSymbolSymbol(const MachineOperand &MO) const;
 };
 }
 

diff --git a/test/CodeGen/BPF/cc_args.ll b/test/CodeGen/BPF/cc_args.ll
index 4ad7a22c7e2ea6312f65456d08eebaf0a52bf205..a2ac03f0da1201e9f3549a5e95e7c2447cc5be42 100644 (file)
--- a/test/CodeGen/BPF/cc_args.ll
+++ b/test/CodeGen/BPF/cc_args.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpfel -show-mc-encoding | FileCheck %s
+; RUN: not llc < %s -march=bpfel -show-mc-encoding | FileCheck %s
 
 define void @test() #0 {
 entry:

diff --git a/test/CodeGen/BPF/cc_args_be.ll b/test/CodeGen/BPF/cc_args_be.ll
index 4d1efccf516068a6d8bec31238162642f7a94526..dc41ee0d8a7d0490f3a4ff5095cb3f5003fac69d 100644 (file)
--- a/test/CodeGen/BPF/cc_args_be.ll
+++ b/test/CodeGen/BPF/cc_args_be.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpfeb -show-mc-encoding | FileCheck %s
+; RUN: not llc < %s -march=bpfeb -show-mc-encoding | FileCheck %s
 ; test big endian
 
 define void @test() #0 {

diff --git a/test/CodeGen/BPF/cc_ret.ll b/test/CodeGen/BPF/cc_ret.ll
index 7bd01adc6ded5cc5cf09cf505765a7e25c2bb908..eab2a359b8f230de2e0babbba8d1c7400011567b 100644 (file)
--- a/test/CodeGen/BPF/cc_ret.ll
+++ b/test/CodeGen/BPF/cc_ret.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpfel | FileCheck %s
+; RUN: not llc < %s -march=bpfel | FileCheck %s
 
 define void @test() #0 {
 entry:

diff --git a/test/CodeGen/BPF/fi_ri.ll b/test/CodeGen/BPF/fi_ri.ll
index 12452988e8a9b175220243f9d85ebbf8bc157814..6ecc826796915fd724f12550a59ec30246193641 100644 (file)
--- a/test/CodeGen/BPF/fi_ri.ll
+++ b/test/CodeGen/BPF/fi_ri.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpf | FileCheck %s
+; RUN: not llc < %s -march=bpf | FileCheck %s
 
 %struct.key_t = type { i32, [16 x i8] }
 

diff --git a/test/CodeGen/BPF/intrinsics.ll b/test/CodeGen/BPF/intrinsics.ll
index e7a9de88cbb2cb14fa699940338014296dadadcf..88aba805adadbfc49a270718a8c159ebb5f3a6d5 100644 (file)
--- a/test/CodeGen/BPF/intrinsics.ll
+++ b/test/CodeGen/BPF/intrinsics.ll
@@ -52,14 +52,12 @@ declare i64 @llvm.bpf.load.word(i8*, i64) #1
 define i32 @ld_pseudo() #0 {
 entry:
   %call = tail call i64 @llvm.bpf.pseudo(i64 2, i64 3)
-  tail call void @bar(i64 %call, i32 4) #2
+  tail call void inttoptr (i64 4 to void (i64, i32)*)(i64 %call, i32 4) #2
   ret i32 0
 ; CHECK-LABEL: ld_pseudo:
 ; CHECK: ld_pseudo r1, 2, 3 # encoding: [0x18,0x21,0x00,0x00,0x03,0x00
 }
 
-declare void @bar(i64, i32) #1
-
 declare i64 @llvm.bpf.pseudo(i64, i64) #2
 
 define i32 @bswap(i64 %a, i64 %b, i64 %c) #0 {

diff --git a/test/CodeGen/BPF/objdump_intrinsics.ll b/test/CodeGen/BPF/objdump_intrinsics.ll
index ddb92b9d8fba4d912195c1ee0a16469a6caa7a99..1d33e57de789d900bcb89ceb9cf8104be15eb4c4 100644 (file)
--- a/test/CodeGen/BPF/objdump_intrinsics.ll
+++ b/test/CodeGen/BPF/objdump_intrinsics.ll
@@ -52,14 +52,12 @@ declare i64 @llvm.bpf.load.word(i8*, i64) #1
 define i32 @ld_pseudo() #0 {
 entry:
   %call = tail call i64 @llvm.bpf.pseudo(i64 2, i64 3)
-  tail call void @bar(i64 %call, i32 4) #2
+  tail call void inttoptr (i64 4 to void (i64, i32)*)(i64 %call, i32 4) #2
   ret i32 0
 ; CHECK-LABEL: ld_pseudo:
 ; CHECK: ld_pseudo r1, 2, 3
 }
 
-declare void @bar(i64, i32) #1
-
 declare i64 @llvm.bpf.pseudo(i64, i64) #2
 
 define i32 @bswap(i64 %a, i64 %b, i64 %c) #0 {

diff --git a/test/CodeGen/BPF/objdump_trivial.ll b/test/CodeGen/BPF/objdump_trivial.ll
index 48fee21a2e4cf3fda00ed6d6839995763c060c2c..6b5423854ee77d9b19af7a88e5ef6cb2d659e21e 100644 (file)
--- a/test/CodeGen/BPF/objdump_trivial.ll
+++ b/test/CodeGen/BPF/objdump_trivial.ll
@@ -1,19 +1,18 @@
 ; RUN: llc -march=bpfel -filetype=obj -o - %s | llvm-objdump -d - | FileCheck %s
 
 ; CHECK: if r2 s> r1 goto
-; CHECK: call
+; CHECK: call 1
+; CHECK: exit
+; CHECK: call 2
 ; CHECK: exit
-
-declare void @a()
-declare void @b()
 
 define void @foo(i32 %a) {
 %b = icmp sgt i32 %a, -1
 br i1 %b, label %x, label %y
 x:
-call void @a()
+call void inttoptr (i64 1 to void ()*)()
 ret void
 y:
-call void @b()
+call void inttoptr (i64 2 to void ()*)()
 ret void
 }

diff --git a/test/CodeGen/BPF/sanity.ll b/test/CodeGen/BPF/sanity.ll
index f318c3a95e48923bfb61e7028a364c3d207b8329..a7aed65b821e398d953c88b6dc1e760405213f07 100644 (file)
--- a/test/CodeGen/BPF/sanity.ll
+++ b/test/CodeGen/BPF/sanity.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpfel | FileCheck %s
+; RUN: not llc < %s -march=bpfel | FileCheck %s
 
 @foo_printf.fmt = private unnamed_addr constant [9 x i8] c"hello  \0A\00", align 1
 

diff --git a/test/CodeGen/BPF/undef.ll b/test/CodeGen/BPF/undef.ll
index 1a925ccae803182f03fcce3f435f79768e2a895f..541d81ea07b738188823f506b5309337bc66e751 100644 (file)
--- a/test/CodeGen/BPF/undef.ll
+++ b/test/CodeGen/BPF/undef.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=bpf | FileCheck %s
+; RUN: not llc < %s -march=bpf | FileCheck %s
 
 %struct.bpf_map_def = type { i32, i32, i32, i32 }
 %struct.__sk_buff = type opaque

diff --git a/test/CodeGen/BPF/warn-call.ll b/test/CodeGen/BPF/warn-call.ll
new file mode 100644 (file)
index 0000000..ae7f78a
--- /dev/null
+++ b/test/CodeGen/BPF/warn-call.ll
@@ -0,0 +1,69 @@
+; RUN: not llc -march=bpfel < %s 2>&1 >/dev/null | FileCheck %s
+
+; CHECK: error: warn_call.c
+; CHECK: built-in function 'memcpy'
+; CHECK: error: warn_call.c
+; CHECK: global function 'foo'
+; CHECK: global function 'bar'
+define i8* @warn(i8* returned, i8*, i64) local_unnamed_addr #0 !dbg !6 {
+  tail call void @llvm.dbg.value(metadata i8* %0, i64 0, metadata !14, metadata !17), !dbg !18
+  tail call void @llvm.dbg.value(metadata i8* %1, i64 0, metadata !15, metadata !17), !dbg !19
+  tail call void @llvm.dbg.value(metadata i64 %2, i64 0, metadata !16, metadata !17), !dbg !20
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 %2, i32 1, i1 false), !dbg !21
+  %4 = tail call i8* @foo(i8* %0, i8* %1, i64 %2) #5, !dbg !22
+  %5 = tail call fastcc i8* @bar(i8* %0), !dbg !23
+  ret i8* %5, !dbg !24
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1) #1
+
+declare i8* @foo(i8*, i8*, i64) local_unnamed_addr #2
+
+; Function Attrs: noinline nounwind readnone
+define internal fastcc i8* @bar(i8* readnone returned) unnamed_addr #3 !dbg !25 {
+  tail call void @llvm.dbg.value(metadata i8* null, i64 0, metadata !28, metadata !17), !dbg !30
+  tail call void @llvm.dbg.value(metadata i64 0, i64 0, metadata !29, metadata !17), !dbg !31
+  ret i8* %0, !dbg !32
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #4
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 5.0.0 (trunk 292174) (llvm/trunk 292179)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "warn_call.c", directory: "/w/llvm/bld")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{!"clang version 5.0.0 (trunk 292174) (llvm/trunk 292179)"}
+!6 = distinct !DISubprogram(name: "warn", scope: !1, file: !1, line: 4, type: !7, isLocal: false, isDefinition: true, scopeLine: 5, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !13)
+!7 = !DISubroutineType(types: !8)
+!8 = !{!9, !9, !10, !12}
+!9 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !11, size: 64)
+!11 = !DIDerivedType(tag: DW_TAG_const_type, baseType: null)
+!12 = !DIBasicType(name: "long unsigned int", size: 64, encoding: DW_ATE_unsigned)
+!13 = !{!14, !15, !16}
+!14 = !DILocalVariable(name: "dst", arg: 1, scope: !6, file: !1, line: 4, type: !9)
+!15 = !DILocalVariable(name: "src", arg: 2, scope: !6, file: !1, line: 4, type: !10)
+!16 = !DILocalVariable(name: "len", arg: 3, scope: !6, file: !1, line: 4, type: !12)
+!17 = !DIExpression()
+!18 = !DILocation(line: 4, column: 18, scope: !6)
+!19 = !DILocation(line: 4, column: 35, scope: !6)
+!20 = !DILocation(line: 4, column: 54, scope: !6)
+!21 = !DILocation(line: 6, column: 2, scope: !6)
+!22 = !DILocation(line: 7, column: 2, scope: !6)
+!23 = !DILocation(line: 8, column: 9, scope: !6)
+!24 = !DILocation(line: 8, column: 2, scope: !6)
+!25 = distinct !DISubprogram(name: "bar", scope: !1, file: !1, line: 2, type: !7, isLocal: true, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !26)
+!26 = !{!27, !28, !29}
+!27 = !DILocalVariable(name: "dst", arg: 1, scope: !25, file: !1, line: 2, type: !9)
+!28 = !DILocalVariable(name: "src", arg: 2, scope: !25, file: !1, line: 2, type: !10)
+!29 = !DILocalVariable(name: "len", arg: 3, scope: !25, file: !1, line: 2, type: !12)
+!30 = !DILocation(line: 2, column: 67, scope: !25)
+!31 = !DILocation(line: 2, column: 86, scope: !25)
+!32 = !DILocation(line: 2, column: 93, scope: !25)