[llvm] r317730 - Let replaceVTableHolder accept any type.
Maxim Kuvyrkov via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 9 22:49:32 PST 2017
> 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.
--
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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