[llvm] r351910 - [CodeView] Allow empty types in member functions

[Tom Stellard via llvm-commits]

On 01/22/2019 04:53 PM, Josh Stone via llvm-commits wrote:
> Author: cuviper
> Date: Tue Jan 22 16:53:22 2019
> New Revision: 351910
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=351910&view=rev
> Log:
> [CodeView] Allow empty types in member functions
> 
> Summary:
> `CodeViewDebug::lowerTypeMemberFunction` used to default to a `Void`
> return type if the function's type array was empty. After D54667, it
> started blindly indexing the 0th item for the return type, which fails
> in `getOperand` for empty arrays if assertions are enabled.
> 
> This patch restores the `Void` return type for empty type arrays, and
> adds a test generated by Rust in line-only debuginfo mode.
> 

Hi Hans,

Can this be cherry-picked to the release_80 branch?

-Tom

> Reviewers: zturner, rnk
> 
> Reviewed By: rnk
> 
> Subscribers: hiraditya, JDevlieghere, llvm-commits
> 
> Differential Revision: https://reviews.llvm.org/D57070
> 
> Added:
>     llvm/trunk/test/DebugInfo/COFF/types-empty-member-fn.ll
> Modified:
>     llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
> 
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp?rev=351910&r1=351909&r2=351910&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp Tue Jan 22 16:53:22 2019
> @@ -1835,7 +1835,10 @@ TypeIndex CodeViewDebug::lowerTypeMember
>  
>    unsigned Index = 0;
>    SmallVector<TypeIndex, 8> ArgTypeIndices;
> -  TypeIndex ReturnTypeIndex = getTypeIndex(ReturnAndArgs[Index++]);
> +  TypeIndex ReturnTypeIndex = TypeIndex::Void();
> +  if (ReturnAndArgs.size() > Index) {
> +    ReturnTypeIndex = getTypeIndex(ReturnAndArgs[Index++]);
> +  }
>  
>    // If the first argument is a pointer type and this isn't a static method,
>    // treat it as the special 'this' parameter, which is encoded separately from
> 
> Added: llvm/trunk/test/DebugInfo/COFF/types-empty-member-fn.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/COFF/types-empty-member-fn.ll?rev=351910&view=auto
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/COFF/types-empty-member-fn.ll (added)
> +++ llvm/trunk/test/DebugInfo/COFF/types-empty-member-fn.ll Tue Jan 22 16:53:22 2019
> @@ -0,0 +1,72 @@
> +; RUN: llc < %s -filetype=obj | llvm-readobj - -codeview | FileCheck %s
> +
> +; ModuleID = 'foo.3a1fbbbh-cgu.0'
> +source_filename = "foo.3a1fbbbh-cgu.0"
> +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
> +target triple = "x86_64-pc-windows-msvc"
> +
> +; Rust source to regenerate:
> +; $ cat foo.rs
> +; pub struct Foo;
> +; impl Foo {
> +;     pub fn foo() {}
> +; }
> +; $ rustc foo.rs --crate-type lib -Cdebuginfo=1 --emit=llvm-ir
> +
> +; CHECK:      CodeViewTypes [
> +; CHECK:        MemberFunction (0x1006) {
> +; CHECK-NEXT:     TypeLeafKind: LF_MFUNCTION (0x1009)
> +; CHECK-NEXT:     ReturnType: void (0x3)
> +; CHECK-NEXT:     ClassType: foo::Foo (0x1000)
> +; CHECK-NEXT:     ThisType: 0x0
> +; CHECK-NEXT:     CallingConvention: NearC (0x0)
> +; CHECK-NEXT:     FunctionOptions [ (0x0)
> +; CHECK-NEXT:     ]
> +; CHECK-NEXT:     NumParameters: 0
> +; CHECK-NEXT:     ArgListType: () (0x1005)
> +; CHECK-NEXT:     ThisAdjustment: 0
> +; CHECK-NEXT:   }
> +; CHECK-NEXT:   MemberFuncId (0x1007) {
> +; CHECK-NEXT:     TypeLeafKind: LF_MFUNC_ID (0x1602)
> +; CHECK-NEXT:     ClassType: foo::Foo (0x1000)
> +; CHECK-NEXT:     FunctionType: void foo::Foo::() (0x1006)
> +; CHECK-NEXT:     Name: foo
> +; CHECK-NEXT:   }
> +; CHECK:      CodeViewDebugInfo [
> +; CHECK:        FunctionLineTable [
> +; CHECK-NEXT:     LinkageName: _ZN3foo3Foo3foo17hc557c2121772885bE
> +; CHECK-NEXT:     Flags: 0x0
> +; CHECK-NEXT:     CodeSize: 0x1
> +; CHECK-NEXT:     FilenameSegment [
> +; CHECK-NEXT:       Filename: D:\rust\foo.rs (0x0)
> +; CHECK-NEXT:       +0x0 [
> +; CHECK-NEXT:         LineNumberStart: 3
> +; CHECK-NEXT:         LineNumberEndDelta: 0
> +; CHECK-NEXT:         IsStatement: No
> +; CHECK-NEXT:       ]
> +; CHECK-NEXT:     ]
> +; CHECK-NEXT:   ]
> +
> +; foo::Foo::foo
> +; Function Attrs: uwtable
> +define void @_ZN3foo3Foo3foo17hc557c2121772885bE() unnamed_addr #0 !dbg !5 {
> +start:
> +  ret void, !dbg !10
> +}
> +
> +attributes #0 = { uwtable "target-cpu"="x86-64" }
> +
> +!llvm.dbg.cu = !{!0}
> +!llvm.module.flags = !{!3, !4}
> +
> +!0 = distinct !DICompileUnit(language: DW_LANG_Rust, file: !1, producer: "clang LLVM (rustc version 1.33.0-nightly (8b0f0156e 2019-01-22))", isOptimized: false, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
> +!1 = !DIFile(filename: "foo.rs", directory: "D:\5Crust")
> +!2 = !{}
> +!3 = !{i32 2, !"CodeView", i32 1}
> +!4 = !{i32 2, !"Debug Info Version", i32 3}
> +!5 = distinct !DISubprogram(name: "foo", linkageName: "_ZN3foo3Foo3foo17hc557c2121772885bE", scope: !6, file: !1, line: 3, type: !9, scopeLine: 3, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, templateParams: !2, retainedNodes: !2)
> +!6 = !DICompositeType(tag: DW_TAG_structure_type, name: "Foo", scope: !8, file: !7, align: 8, elements: !2, templateParams: !2, identifier: "5105d9fe1a2a3c68518268151b672274")
> +!7 = !DIFile(filename: "<unknown>", directory: "")
> +!8 = !DINamespace(name: "foo", scope: null)
> +!9 = !DISubroutineType(types: !2)
> +!10 = !DILocation(line: 3, scope: !5)
> 
> 
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