[llvm] r317730 - Let replaceVTableHolder accept any type.
Adrian Prantl via llvm-commits
llvm-commits at lists.llvm.org
Fri Nov 10 08:36:27 PST 2017
> On Nov 9, 2017, at 10:49 PM, Maxim Kuvyrkov <maxim.kuvyrkov at linaro.org> wrote:
>
>> On Nov 10, 2017, at 7:47 AM, Yung, Douglas via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>>
>> Hi Adrian and Tom,
>>
>> The test added in this commit, llvm/trunk/test/DebugInfo/Generic/containing-type-extension-rust.ll contains the following line:
>>
>> target triple = "x86_64-unknown-linux-gnu"
>>
>> This causes it to fail on compilers that do not include x86 as a target:
>>
>> http://lab.llvm.org:8011/builders/clang-cmake-armv7-a15/builds/12905
>>
>> Perhaps this test should be moved to the X86 directory?
>
> Yes, please. Most ARM and AArch64 buildbots are failing because of this change.
>
Done in r317896.
-- adrian
> --
> Maxim Kuvyrkov
> www.linaro.org
>
>
>>
>> Douglas Yung
>>
>>> -----Original Message-----
>>> From: llvm-commits [mailto:llvm-commits-bounces at lists.llvm.org] On Behalf Of
>>> Adrian Prantl via llvm-commits
>>> Sent: Wednesday, November 08, 2017 14:05
>>> To: llvm-commits at lists.llvm.org
>>> Subject: [llvm] r317730 - Let replaceVTableHolder accept any type.
>>>
>>> Author: adrian
>>> Date: Wed Nov 8 14:04:43 2017
>>> New Revision: 317730
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=317730&view=rev
>>> Log:
>>> Let replaceVTableHolder accept any type.
>>>
>>> In Rust, a trait can be implemented for any type, and if a trait object
>>> pointer is used for the type, then a virtual table will be emitted for that
>>> trait/type combination.
>>>
>>> We would like debuggers to be able to inspect trait objects, which requires
>>> finding the concrete type associated with a given vtable.
>>>
>>> This patch changes LLVM so that any type can be passed to replaceVTableHolder.
>>> This allows the Rust compiler to emit the needed debug info -- associating a
>>> vtable with the concrete type for which it was emitted.
>>>
>>> This is a DWARF extension: DWARF only specifies the meaning of
>>> DW_AT_containing_type in one specific situation. This style of DWARF extension
>>> is routine, though, and LLVM already has one such case for
>>> DW_AT_containing_type.
>>>
>>> Patch by Tom Tromey!
>>>
>>> Differential Revision: https://reviews.llvm.org/D39503
>>>
>>> Added:
>>> llvm/trunk/test/DebugInfo/Generic/containing-type-extension-rust.ll
>>> llvm/trunk/test/DebugInfo/Generic/containing-type-extension.ll
>>> Modified:
>>> llvm/trunk/include/llvm/IR/DIBuilder.h
>>> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>>> llvm/trunk/lib/IR/DIBuilder.cpp
>>> llvm/trunk/unittests/IR/MetadataTest.cpp
>>>
>>> Modified: llvm/trunk/include/llvm/IR/DIBuilder.h
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/include/llvm/IR/DIBuilder.h?rev=317730&r1=317729&r2=317730&
>>> view=diff
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/IR/DIBuilder.h (original)
>>> +++ llvm/trunk/include/llvm/IR/DIBuilder.h Wed Nov 8 14:04:43 2017
>>> @@ -757,12 +757,12 @@ namespace llvm {
>>> const DILocation *DL,
>>> Instruction *InsertBefore);
>>>
>>> - /// Replace the vtable holder in the given composite type.
>>> + /// Replace the vtable holder in the given type.
>>> ///
>>> /// If this creates a self reference, it may orphan some unresolved
>>> cycles
>>> /// in the operands of \c T, so \a DIBuilder needs to track that.
>>> void replaceVTableHolder(DICompositeType *&T,
>>> - DICompositeType *VTableHolder);
>>> + DIType *VTableHolder);
>>>
>>> /// Replace arrays on a composite type.
>>> ///
>>>
>>> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=317730&r1=317729&r
>>> 2=317730&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
>>> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Wed Nov 8 14:04:43
>>> +++ 2017
>>> @@ -960,8 +960,9 @@ void DwarfUnit::constructTypeDIE(DIE &Bu
>>>
>>> // This is outside the DWARF spec, but GDB expects a
>>> DW_AT_containing_type
>>> // inside C++ composite types to point to the base class with the vtable.
>>> - if (auto *ContainingType =
>>> - dyn_cast_or_null<DICompositeType>(resolve(CTy-
>>>> getVTableHolder())))
>>> + // Rust uses DW_AT_containing_type to link a vtable to the type
>>> + // for which it was created.
>>> + if (auto *ContainingType = resolve(CTy->getVTableHolder()))
>>> addDIEEntry(Buffer, dwarf::DW_AT_containing_type,
>>> *getOrCreateTypeDIE(ContainingType));
>>>
>>>
>>> Modified: llvm/trunk/lib/IR/DIBuilder.cpp
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/lib/IR/DIBuilder.cpp?rev=317730&r1=317729&r2=317730&view=di
>>> ff
>>> ==============================================================================
>>> --- llvm/trunk/lib/IR/DIBuilder.cpp (original)
>>> +++ llvm/trunk/lib/IR/DIBuilder.cpp Wed Nov 8 14:04:43 2017
>>> @@ -874,7 +874,7 @@ Instruction *DIBuilder::insertDbgValueIn }
>>>
>>> void DIBuilder::replaceVTableHolder(DICompositeType *&T,
>>> - DICompositeType *VTableHolder) {
>>> + DIType *VTableHolder) {
>>> {
>>> TypedTrackingMDRef<DICompositeType> N(T);
>>> N->replaceVTableHolder(VTableHolder);
>>>
>>> Added: llvm/trunk/test/DebugInfo/Generic/containing-type-extension-rust.ll
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/test/DebugInfo/Generic/containing-type-extension-
>>> rust.ll?rev=317730&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/test/DebugInfo/Generic/containing-type-extension-rust.ll
>>> (added)
>>> +++ llvm/trunk/test/DebugInfo/Generic/containing-type-extension-rust.ll
>>> +++ Wed Nov 8 14:04:43 2017
>>> @@ -0,0 +1,125 @@
>>> +; REQUIRES: object-emission
>>> +
>>> +; RUN: %llc_dwarf -O0 -filetype=obj < %s > %t ; RUN: llvm-dwarfdump -v
>>> +-debug-info %t | FileCheck %s
>>> +
>>> +; Check that any type can have a vtable holder.
>>> +; CHECK: [[SP:.*]]: DW_TAG_structure_type ; CHECK-NOT: TAG ; CHECK:
>>> +DW_AT_containing_type [DW_FORM_ref4] ; CHECK: DW_AT_name [DW_FORM_strp]
>>> +{{.*}}= "vtable")
>>> +
>>> +; This was compiled using
>>> +; rustc -g --emit=llvm-ir t2.rs
>>> +; ... and then edited by hand, because rustc is using a somewhat older llvm.
>>> +;
>>> +; t2.rs is:
>>> +;
>>> +; // trait object test case
>>> +;
>>> +; pub trait T {
>>> +; }
>>> +;
>>> +; impl T for f64 {
>>> +; }
>>> +;
>>> +; pub fn main() {
>>> +; let tu = &23.0f64 as &T;
>>> +; }
>>> +; t2.rs ends here ^^^
>>> +
>>> +; ModuleID = 't2.cgu-0.rs'
>>> +source_filename = "t2.cgu-0.rs"
>>> +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
>>> +target triple = "x86_64-unknown-linux-gnu"
>>> +
>>> + at ref.0 = internal unnamed_addr constant double 2.300000e+01, align 8
>>> + at vtable.1 = internal unnamed_addr constant { void (double*)*, i64, i64
>>> +} { void (double*)* @_ZN4core3ptr13drop_in_place17h2818a933abde117eE,
>>> +i64 8, i64 8 }, align 8, !dbg !0 @__rustc_debug_gdb_scripts_section__ =
>>> +linkonce_odr unnamed_addr constant [34 x i8]
>>> +c"\01gdb_load_rust_pretty_printers.py\00", section
>>> +".debug_gdb_scripts", align 1
>>> +
>>> +; core::ptr::drop_in_place
>>> +; Function Attrs: uwtable
>>> +define internal void
>>> + at _ZN4core3ptr13drop_in_place17h2818a933abde117eE(double*) unnamed_addr
>>> +#0 !dbg !11 {
>>> +start:
>>> + %arg0 = alloca double*
>>> + store double* %0, double** %arg0
>>> + call void @llvm.dbg.declare(metadata double** %arg0, metadata !20,
>>> +metadata !22), !dbg !23
>>> + ret void, !dbg !24
>>> +}
>>> +
>>> +; t2::main
>>> +; Function Attrs: uwtable
>>> +define internal void @_ZN2t24main17h6319e6ac7de3a097E() unnamed_addr #0
>>> +!dbg !25 {
>>> +start:
>>> + %tu = alloca { i8*, void (i8*)** }
>>> + call void @llvm.dbg.declare(metadata { i8*, void (i8*)** }* %tu,
>>> +metadata !29, metadata !22), !dbg !37
>>> + %0 = getelementptr inbounds { i8*, void (i8*)** }, { i8*, void
>>> +(i8*)** }* %tu, i32 0, i32 0, !dbg !37
>>> + store i8* bitcast (double* @ref.0 to i8*), i8** %0, !dbg !37
>>> + %1 = getelementptr inbounds { i8*, void (i8*)** }, { i8*, void
>>> +(i8*)** }* %tu, i32 0, i32 1, !dbg !37
>>> + store void (i8*)** bitcast ({ void (double*)*, i64, i64 }* @vtable.1
>>> +to void (i8*)**), void (i8*)*** %1, !dbg !37
>>> + ret void, !dbg !38
>>> +}
>>> +
>>> +; Function Attrs: nounwind readnone
>>> +declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
>>> +
>>> +define i32 @main(i32, i8**) unnamed_addr #2 {
>>> +top:
>>> + %2 = load volatile i8, i8* getelementptr inbounds ([34 x i8], [34 x
>>> +i8]* @__rustc_debug_gdb_scripts_section__, i32 0, i32 0), align 1
>>> + %3 = sext i32 %0 to i64
>>> +; call std::rt::lang_start
>>> + %4 = call i64 @_ZN3std2rt10lang_start17h2626caf1112a00beE(void ()*
>>> + at _ZN2t24main17h6319e6ac7de3a097E, i64 %3, i8** %1)
>>> + %5 = trunc i64 %4 to i32
>>> + ret i32 %5
>>> +}
>>> +
>>> +; std::rt::lang_start
>>> +declare i64 @_ZN3std2rt10lang_start17h2626caf1112a00beE(void ()*, i64,
>>> +i8**) unnamed_addr #3
>>> +
>>> +attributes #0 = { uwtable "no-frame-pointer-elim"="true"
>>> +"probe-stack"="__rust_probestack" } attributes #1 = { nounwind readnone
>>> +} attributes #2 = { "no-frame-pointer-elim"="true" } attributes #3 = {
>>> +"no-frame-pointer-elim"="true" "probe-stack"="__rust_probestack" }
>>> +
>>> +!llvm.module.flags = !{!6, !7}
>>> +!llvm.dbg.cu = !{!8}
>>> +
>>> +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
>>> +!1 = distinct !DIGlobalVariable(name: "vtable", scope: null, file: !2,
>>> +type: !3, isLocal: true, isDefinition: true)
>>> +!2 = !DIFile(filename: "<unknown>", directory: "")
>>> +!3 = !DICompositeType(tag: DW_TAG_structure_type, name: "vtable", file:
>>> +!2, size: 64, align: 64, flags: DIFlagArtificial, elements: !4,
>>> +vtableHolder: !5, identifier: "vtable")
>>> +!4 = !{}
>>> +!5 = !DIBasicType(name: "f64", size: 64, encoding: DW_ATE_float)
>>> +!6 = !{i32 1, !"PIE Level", i32 2}
>>> +!7 = !{i32 2, !"Debug Info Version", i32 3}
>>> +!8 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !9,
>>> +producer: "clang LLVM (rustc version 1.22.0-dev)", isOptimized: false,
>>> +runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !10)
>>> +!9 = !DIFile(filename: "t2.rs", directory: "/home/tromey/Rust")
>>> +!10 = !{!0}
>>> +!11 = distinct !DISubprogram(name: "drop_in_place<f64>", linkageName:
>>> +"_ZN4core3ptr18drop_in_place<f64>E", scope: !13, file: !12, line: 59,
>>> +type: !15, isLocal: false, isDefinition: true, scopeLine: 59, flags:
>>> +DIFlagPrototyped, isOptimized: false, unit: !8, templateParams: !18,
>>> +variables: !4)
>>> +!12 = !DIFile(filename: "/home/tromey/Rust/rust/src/libcore/ptr.rs",
>>> +directory: "")
>>> +!13 = !DINamespace(name: "ptr", scope: !14)
>>> +!14 = !DINamespace(name: "core", scope: null)
>>> +!15 = !DISubroutineType(types: !16)
>>> +!16 = !{null, !17}
>>> +!17 = !DIDerivedType(tag: DW_TAG_pointer_type, name: "*mut f64",
>>> +baseType: !5, size: 64, align: 64)
>>> +!18 = !{!19}
>>> +!19 = !DITemplateTypeParameter(name: "T", type: !5)
>>> +!20 = !DILocalVariable(arg: 1, scope: !11, file: !21, line: 1, type:
>>> +!17)
>>> +!21 = !DIFile(filename: "t2.rs", directory: "")
>>> +!22 = !DIExpression()
>>> +!23 = !DILocation(line: 1, scope: !11)
>>> +!24 = !DILocation(line: 59, scope: !11)
>>> +!25 = distinct !DISubprogram(name: "main", linkageName: "_ZN2t24mainE",
>>> +scope: !26, file: !9, line: 9, type: !27, isLocal: true, isDefinition:
>>> +true, scopeLine: 9, flags: DIFlagPrototyped | DIFlagMainSubprogram,
>>> +isOptimized: false, unit: !8, templateParams: !4, variables: !4)
>>> +!26 = !DINamespace(name: "t2", scope: null)
>>> +!27 = !DISubroutineType(types: !28)
>>> +!28 = !{null}
>>> +!29 = !DILocalVariable(name: "tu", scope: !30, file: !9, line: 10,
>>> +type: !31, align: 8)
>>> +!30 = distinct !DILexicalBlock(scope: !25, file: !9, line: 10, column:
>>> +4)
>>> +!31 = !DICompositeType(tag: DW_TAG_structure_type, name: "&T", scope:
>>> +!26, file: !2, size: 128, align: 64, elements: !32, identifier:
>>> +"b9f642b757d8ad3984c1e721e3ce6016d14d9322")
>>> +!32 = !{!33, !36}
>>> +!33 = !DIDerivedType(tag: DW_TAG_member, name: "pointer", scope: !31,
>>> +file: !2, baseType: !34, size: 64, align: 64, flags: DIFlagArtificial)
>>> +!34 = !DIDerivedType(tag: DW_TAG_pointer_type, name: "*const u8",
>>> +baseType: !35, size: 64, align: 64)
>>> +!35 = !DIBasicType(name: "u8", size: 8, encoding: DW_ATE_unsigned)
>>> +!36 = !DIDerivedType(tag: DW_TAG_member, name: "vtable", scope: !31,
>>> +file: !2, baseType: !34, size: 64, align: 64, offset: 64, flags:
>>> +DIFlagArtificial)
>>> +!37 = !DILocation(line: 10, scope: !30)
>>> +!38 = !DILocation(line: 11, scope: !25)
>>>
>>> Added: llvm/trunk/test/DebugInfo/Generic/containing-type-extension.ll
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/test/DebugInfo/Generic/containing-type-
>>> extension.ll?rev=317730&view=auto
>>> ==============================================================================
>>> --- llvm/trunk/test/DebugInfo/Generic/containing-type-extension.ll (added)
>>> +++ llvm/trunk/test/DebugInfo/Generic/containing-type-extension.ll Wed
>>> +++ Nov 8 14:04:43 2017
>>> @@ -0,0 +1,39 @@
>>> +; REQUIRES: object-emission
>>> +
>>> +; RUN: %llc_dwarf -O0 -filetype=obj < %s > %t ; RUN: llvm-dwarfdump -v
>>> +-debug-info %t | FileCheck %s
>>> +
>>> +; Check that any type can have a vtable holder.
>>> +; CHECK: [[SP:.*]]: DW_TAG_structure_type ; CHECK-NOT: TAG ; CHECK:
>>> +DW_AT_containing_type [DW_FORM_ref4] ; CHECK: DW_AT_name [DW_FORM_strp]
>>> +{{.*}}= "vtable")
>>> +
>>> +; The code doesn't actually matter.
>>> +define i32 @main() #0 !dbg !4 {
>>> +entry:
>>> + %retval = alloca i32, align 4
>>> + store i32 0, i32* %retval
>>> + ret i32 0, !dbg !10
>>> +}
>>> +
>>> +attributes #0 = { nounwind uwtable }
>>> +
>>> +!llvm.dbg.cu = !{!0}
>>> +!llvm.module.flags = !{!9, !11}
>>> +
>>> +!0 = distinct !DICompileUnit(language: DW_LANG_Rust, producer: "clang
>>> +version 3.4 (trunk 185475)", isOptimized: false, emissionKind:
>>> +FullDebug, file: !1, enums: !2, retainedTypes: !2, globals: !15,
>>> +imports: !2)
>>> +!1 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
>>> +!2 = !{}
>>> +!4 = distinct !DISubprogram(name: "main", line: 6, isLocal: false,
>>> +isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped |
>>> +DIFlagMainSubprogram, isOptimized: false, unit: !0, scopeLine: 6, file:
>>> +!1, scope: !5, type: !6, variables: !2)
>>> +!5 = !DIFile(filename: "CodeGen/dwarf-version.c", directory: "test")
>>> +!6 = !DISubroutineType(types: !7)
>>> +!7 = !{!8}
>>> +!8 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align:
>>> +32, encoding: DW_ATE_signed)
>>> +!9 = !{i32 2, !"Dwarf Version", i32 4}
>>> +!10 = !DILocation(line: 7, scope: !4)
>>> +!11 = !{i32 1, !"Debug Info Version", i32 3}
>>> +!12 = !DICompositeType(tag: DW_TAG_structure_type, name: "vtable",
>>> +size: 8, align: 8, elements: !2, identifier: "vtable", vtableHolder:
>>> +!8)
>>> +!13 = !DIGlobalVariableExpression(var: !14, expr: !DIExpression())
>>> +!14 = !DIGlobalVariable(name: "vtable", linkageName: "vtable", scope:
>>> +null, file: !1, line: 1, type: !12, isLocal: true, isDefinition: true)
>>> +!15 = !{!13}
>>>
>>> Modified: llvm/trunk/unittests/IR/MetadataTest.cpp
>>> URL: http://llvm.org/viewvc/llvm-
>>> project/llvm/trunk/unittests/IR/MetadataTest.cpp?rev=317730&r1=317729&r2=31773
>>> 0&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/unittests/IR/MetadataTest.cpp (original)
>>> +++ llvm/trunk/unittests/IR/MetadataTest.cpp Wed Nov 8 14:04:43 2017
>>> @@ -1314,6 +1314,11 @@ TEST_F(DICompositeTypeTest, replaceOpera
>>> EXPECT_EQ(nullptr, N->getVTableHolder());
>>> N->replaceVTableHolder(VTableHolder);
>>> EXPECT_EQ(VTableHolder, N->getVTableHolder());
>>> + // As an extension, the containing type can be anything. This is //
>>> + used by Rust to associate vtables with their concrete type.
>>> + DIType *BasicType = getBasicType("basic");
>>> + N->replaceVTableHolder(BasicType);
>>> + EXPECT_EQ(BasicType, N->getVTableHolder());
>>> N->replaceVTableHolder(nullptr);
>>> EXPECT_EQ(nullptr, N->getVTableHolder());
>>>
>>>
>>>
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