[llvm] r278967 - [WebAssembly] Handle debug information and virtual registers without crashing

Wed Aug 17 13:51:25 PDT 2016

Reverted in r278973.  I think you need some lit logic so that this only builds when the WebAssembly target is enabled (the bots weren't very happy).

> On 2016-Aug-17, at 13:11, Dominic Chen via llvm-commits <llvm-commits at lists.llvm.org> wrote:
> 
> Author: ddcc
> Date: Wed Aug 17 15:11:03 2016
> New Revision: 278967
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=278967&view=rev
> Log:
> [WebAssembly] Handle debug information and virtual registers without crashing
> 
> Summary: Currently, enabling debug information when compiling for WebAssembly crashes the backend. This commit fixes these by skipping debug values in backend passes.
> 
> Reviewers: jfb, aprantl, dschuff, echristo
> 
> Subscribers: mehdi_amini, yurydelendik, dexonsmith, MatzeB, jfb, dschuff, llvm-commits
> 
> Differential Revision: https://reviews.llvm.org/D21808
> 
> Added:
>    llvm/trunk/test/DebugInfo/WebAssembly/
>    llvm/trunk/test/DebugInfo/WebAssembly/dbg-declare.ll
> Modified:
>    llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
>    llvm/trunk/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp
>    llvm/trunk/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp
> 
> Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp?rev=278967&r1=278966&r2=278967&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp (original)
> +++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp Wed Aug 17 15:11:03 2016
> @@ -255,7 +255,7 @@ static bool HasOneUse(unsigned Reg, Mach
>   const VNInfo *DefVNI = LI.getVNInfoAt(
>       LIS.getInstructionIndex(*Def).getRegSlot());
>   assert(DefVNI);
> -  for (auto I : MRI.use_nodbg_operands(Reg)) {
> +  for (auto &I : MRI.use_nodbg_operands(Reg)) {
>     const auto &Result = LI.Query(LIS.getInstructionIndex(*I.getParent()));
>     if (Result.valueIn() == DefVNI) {
>       if (!Result.isKill())
> @@ -360,7 +360,7 @@ static bool OneUseDominatesOtherUses(uns
>   const MachineInstr *OneUseInst = OneUse.getParent();
>   VNInfo *OneUseVNI = LI.getVNInfoBefore(LIS.getInstructionIndex(*OneUseInst));
> 
> -  for (const MachineOperand &Use : MRI.use_operands(Reg)) {
> +  for (const MachineOperand &Use : MRI.use_nodbg_operands(Reg)) {
>     if (&Use == &OneUse)
>       continue;
> 
> 
> Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp?rev=278967&r1=278966&r2=278967&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp (original)
> +++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyReplacePhysRegs.cpp Wed Aug 17 15:11:03 2016
> @@ -88,6 +88,8 @@ bool WebAssemblyReplacePhysRegs::runOnMa
>         if (VReg == WebAssembly::NoRegister)
>           VReg = MRI.createVirtualRegister(RC);
>         MO.setReg(VReg);
> +        if (MO.getParent()->isDebugValue())
> +          MO.setIsDebug();
>         Changed = true;
>       }
>     }
> 
> Modified: llvm/trunk/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp?rev=278967&r1=278966&r2=278967&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp (original)
> +++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyStoreResults.cpp Wed Aug 17 15:11:03 2016
> @@ -90,7 +90,7 @@ static bool ReplaceDominatedUses(Machine
> 
>   SmallVector<SlotIndex, 4> Indices;
> 
> -  for (auto I = MRI.use_begin(FromReg), E = MRI.use_end(); I != E;) {
> +  for (auto I = MRI.use_nodbg_begin(FromReg), E = MRI.use_nodbg_end(); I != E;) {
>     MachineOperand &O = *I++;
>     MachineInstr *Where = O.getParent();
> 
> 
> Added: llvm/trunk/test/DebugInfo/WebAssembly/dbg-declare.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/WebAssembly/dbg-declare.ll?rev=278967&view=auto
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/WebAssembly/dbg-declare.ll (added)
> +++ llvm/trunk/test/DebugInfo/WebAssembly/dbg-declare.ll Wed Aug 17 15:11:03 2016
> @@ -0,0 +1,75 @@
> +; RUN: llc < %s -verify-machineinstrs -mtriple=wasm32-unknown-unknown | FileCheck %s
> +; RUN: llc < %s -verify-machineinstrs -mtriple=wasm32-unknown-unknown -fast-isel | FileCheck --check-prefix=CHECK-FAST %s
> +; CHECK: #DEBUG_VALUE: decode:i <- [%vreg
> +; CHECK: #DEBUG_VALUE: decode:v <- [%vreg
> +; CHECK: DW_TAG_variable
> +; CHECK-FAST: DW_TAG_variable
> +
> +; Test that llvm.dbg.declare() instrinsics do not crash the backend
> +
> +target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
> +target triple = "wasm32-unknown-unknown"
> +
> +%0 = type opaque
> +
> + at key = external global [15 x i8], align 1
> +
> +; Function Attrs: nounwind
> +define internal zeroext i8 @0(i32, i8 zeroext)  !dbg !14 !type !19 {
> +  %3 = alloca i32, align 4
> +  %4 = alloca i8, align 1
> +  store i32 %0, i32* %3, align 4
> +  call void @llvm.dbg.declare(metadata i32* %3, metadata !20, metadata !21), !dbg !22
> +  store i8 %1, i8* %4, align 1
> +  call void @llvm.dbg.declare(metadata i8* %4, metadata !23, metadata !21), !dbg !24
> +  %5 = load i8, i8* %4, align 1, !dbg !25
> +  %6 = zext i8 %5 to i32, !dbg !25
> +  %7 = load i32, i32* %3, align 4, !dbg !26
> +  %8 = urem i32 %7, 15, !dbg !27
> +  %9 = getelementptr inbounds [15 x i8], [15 x i8]* @key, i32 0, i32 %8, !dbg !28
> +  %10 = load i8, i8* %9, align 1, !dbg !28
> +  %11 = zext i8 %10 to i32, !dbg !28
> +  %12 = xor i32 %6, %11, !dbg !29
> +  %13 = trunc i32 %12 to i8, !dbg !30
> +  ret i8 %13, !dbg !31
> +}
> +
> +; Function Attrs: nounwind readnone
> +declare void @llvm.dbg.declare(metadata, metadata, metadata)
> +
> +!llvm.dbg.cu = !{!0}
> +!llvm.module.flags = !{!11, !12}
> +!llvm.ident = !{!13}
> +
> +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 273884) (llvm/trunk 273897)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3)
> +!1 = !DIFile(filename: "crash.c", directory: "wasm/tests")
> +!2 = !{}
> +!3 = !{!4}
> +!4 = distinct !DIGlobalVariable(name: "key", scope: !0, file: !1, line: 7, type: !5, isLocal: false, isDefinition: true, variable: [15 x i8]* @key)
> +!5 = !DICompositeType(tag: DW_TAG_array_type, baseType: !6, size: 120, align: 8, elements: !9)
> +!6 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint8_t", file: !7, line: 185, baseType: !8)
> +!7 = !DIFile(filename: "wasm/emscripten/system/include/libc/bits/alltypes.h", directory: "wasm/tests")
> +!8 = !DIBasicType(name: "unsigned char", size: 8, align: 8, encoding: DW_ATE_unsigned_char)
> +!9 = !{!10}
> +!10 = !DISubrange(count: 15)
> +!11 = !{i32 2, !"Dwarf Version", i32 4}
> +!12 = !{i32 2, !"Debug Info Version", i32 3}
> +!13 = !{!"clang version 3.9.0 (trunk 273884) (llvm/trunk 273897)"}
> +!14 = distinct !DISubprogram(name: "decode", scope: !1, file: !1, line: 11, type: !15, isLocal: false, isDefinition: true, scopeLine: 11, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
> +!15 = !DISubroutineType(types: !16)
> +!16 = !{!6, !17, !6}
> +!17 = !DIDerivedType(tag: DW_TAG_typedef, name: "size_t", file: !7, line: 124, baseType: !18)
> +!18 = !DIBasicType(name: "long unsigned int", size: 32, align: 32, encoding: DW_ATE_unsigned)
> +!19 = !{i64 0, !"_ZTSFhmhE"}
> +!20 = !DILocalVariable(name: "i", arg: 1, scope: !14, file: !1, line: 11, type: !17)
> +!21 = !DIExpression()
> +!22 = !DILocation(line: 11, column: 23, scope: !14)
> +!23 = !DILocalVariable(name: "v", arg: 2, scope: !14, file: !1, line: 11, type: !6)
> +!24 = !DILocation(line: 11, column: 34, scope: !14)
> +!25 = !DILocation(line: 12, column: 11, scope: !14)
> +!26 = !DILocation(line: 12, column: 19, scope: !14)
> +!27 = !DILocation(line: 12, column: 21, scope: !14)
> +!28 = !DILocation(line: 12, column: 15, scope: !14)
> +!29 = !DILocation(line: 12, column: 13, scope: !14)
> +!30 = !DILocation(line: 12, column: 10, scope: !14)
> +!31 = !DILocation(line: 12, column: 3, scope: !14)
> 
> 
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