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Start plumbing through debug info type information with function parameters/return value (#6410)
This adds just enough debug info for i32/int parameters and return
values, with a path forward for adding DWARF type metadata for other
types.
As it happens, return type information is carried separately from
parameter information:
* Return type information is carried in the `type` of the `DISubprogram`
(as a `DISubroutineType` - which does carry parameter type information
as well, but that's unused when the DWARF is emitted by LLVM)
* Parameter information is carried by `DILocalVariable`s with a non-zero
`arg` value (representing the order of function parameters)
In the absence of locations for the parameters (future work), nothing
would usually keep the `DILocalVariable` live/reachable when emitting
DWARF - so for cases where this can happen (for clang, this happens in
optimized builds where all references to the parameter variable might be
optimized away) the variables can be "retained" in a list on the
`DISubprogram` - achieved by passing `AlwaysPreserve` parameter to
`createParameterVariable` (adds them to a list, then that list gets
attached to the `DISubprogram` when it's finalized later)
For now, any unsupported types are emitted as `void*` (except void
return, which is implemented as void) as a placeholder.
Given this example:
```
import Core library "io";
class MyClass {
}
fn Unsupported(v: MyClass) {
}
fn Ret() -> i32 {
return 42;
}
fn Arg(x: i32) {
Core.Print(x);
}
fn Run() {
}
```
this is the resulting DWARF:
```
DW_TAG_compile_unit
DW_AT_name ("test.carbon")
DW_TAG_subprogram
DW_AT_name ("Unsupported")
DW_TAG_formal_parameter
DW_AT_type (0x00000066 "void *")
DW_TAG_subprogram
DW_AT_name ("Ret")
DW_AT_type (0x00000062 "int")
DW_TAG_subprogram
DW_AT_name ("Arg")
DW_TAG_formal_parameter
DW_AT_type (0x00000062 "int")
DW_TAG_subprogram
DW_AT_name ("Run")
DW_TAG_base_type
DW_AT_name ("int")
DW_TAG_pointer_type
```
And the debugger:
```
(gdb) p Ret()
$1 = 42
(gdb) p Arg(4)
4
$2 = void
```
I'm not sure if there's a way this logic should be merged with the logic
for making the `llvm::Function` type (which the `DISubroutineType`
building code was inspired by/copied from) - since they're done at
different times/places, I don't think there's an easy way to do it in
one pass, but maybe the code can be shared (even if it's run twice) in
some generic `SemIR::Function` type walker.
---------
Co-authored-by: Dana Jansens <danakj@orodu.net>
This commit is contained in:
David Blaikie
co-authored by
Dana Jansens
Dana Jansens
parent
0baa74d96f
commit
a179bd461b
+50
-38
@@ -140,26 +140,26 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: ; Function Attrs: nounwind
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// CHECK:STDOUT: define void @_CPassShort.Main(i16 %a, ptr %b) #0 !dbg !17 {
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// CHECK:STDOUT: entry:
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// CHECK:STDOUT: %.loc17_18.1.temp = alloca i16, align 2, !dbg !18
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// CHECK:STDOUT: %.loc18_18.3.temp = alloca i16, align 2, !dbg !19
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// CHECK:STDOUT: %.loc19_18.2.temp = alloca i16, align 2, !dbg !20
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// CHECK:STDOUT: %.loc20_28.3.temp = alloca i16, align 2, !dbg !21
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc17_18.1.temp), !dbg !18
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// CHECK:STDOUT: store i16 %a, ptr %.loc17_18.1.temp, align 2, !dbg !18
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc17_18.1.temp), !dbg !22
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// CHECK:STDOUT: %.loc18_18.2 = load i16, ptr %b, align 2, !dbg !19
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc18_18.3.temp), !dbg !19
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// CHECK:STDOUT: store i16 %.loc18_18.2, ptr %.loc18_18.3.temp, align 2, !dbg !19
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc18_18.3.temp), !dbg !23
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// CHECK:STDOUT: %.loc19_18.1 = load i16, ptr @_Cc.Main, align 2, !dbg !20
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !20
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// CHECK:STDOUT: store i16 %.loc19_18.1, ptr %.loc19_18.2.temp, align 2, !dbg !20
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !24
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// CHECK:STDOUT: %MakeShort.call = call i16 @_CMakeShort.Main(), !dbg !21
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc20_28.3.temp), !dbg !21
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// CHECK:STDOUT: store i16 %MakeShort.call, ptr %.loc20_28.3.temp, align 2, !dbg !21
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc20_28.3.temp), !dbg !25
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// CHECK:STDOUT: ret void, !dbg !26
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// CHECK:STDOUT: %.loc17_18.1.temp = alloca i16, align 2, !dbg !25
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// CHECK:STDOUT: %.loc18_18.3.temp = alloca i16, align 2, !dbg !26
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// CHECK:STDOUT: %.loc19_18.2.temp = alloca i16, align 2, !dbg !27
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// CHECK:STDOUT: %.loc20_28.3.temp = alloca i16, align 2, !dbg !28
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc17_18.1.temp), !dbg !25
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// CHECK:STDOUT: store i16 %a, ptr %.loc17_18.1.temp, align 2, !dbg !25
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc17_18.1.temp), !dbg !29
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// CHECK:STDOUT: %.loc18_18.2 = load i16, ptr %b, align 2, !dbg !26
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc18_18.3.temp), !dbg !26
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// CHECK:STDOUT: store i16 %.loc18_18.2, ptr %.loc18_18.3.temp, align 2, !dbg !26
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc18_18.3.temp), !dbg !30
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// CHECK:STDOUT: %.loc19_18.1 = load i16, ptr @_Cc.Main, align 2, !dbg !27
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc19_18.2.temp), !dbg !27
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// CHECK:STDOUT: store i16 %.loc19_18.1, ptr %.loc19_18.2.temp, align 2, !dbg !27
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc19_18.2.temp), !dbg !31
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// CHECK:STDOUT: %MakeShort.call = call i16 @_CMakeShort.Main(), !dbg !28
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// CHECK:STDOUT: call void @llvm.lifetime.start.p0(ptr %.loc20_28.3.temp), !dbg !28
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// CHECK:STDOUT: store i16 %MakeShort.call, ptr %.loc20_28.3.temp, align 2, !dbg !28
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// CHECK:STDOUT: call void @_Z10pass_shorts.carbon_thunk(ptr %.loc20_28.3.temp), !dbg !32
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// CHECK:STDOUT: ret void, !dbg !33
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
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@@ -244,7 +244,7 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: !6 = !DIFile(filename: "import_ints.carbon", directory: "")
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// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "MyF", linkageName: "_CMyF.Main", scope: null, file: !6, line: 6, type: !8, spFlags: DISPFlagDefinition, unit: !5)
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// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
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// CHECK:STDOUT: !9 = !{}
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// CHECK:STDOUT: !9 = !{null}
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// CHECK:STDOUT: !10 = !DILocation(line: 7, column: 19, scope: !7)
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// CHECK:STDOUT: !11 = !DILocation(line: 7, column: 22, scope: !7)
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// CHECK:STDOUT: !12 = !DILocation(line: 9, column: 21, scope: !7)
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@@ -252,16 +252,23 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: !14 = !DILocation(line: 7, column: 3, scope: !7)
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// CHECK:STDOUT: !15 = !DILocation(line: 9, column: 3, scope: !7)
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// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 1, scope: !7)
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// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "PassShort", linkageName: "_CPassShort.Main", scope: null, file: !6, line: 16, type: !8, spFlags: DISPFlagDefinition, unit: !5)
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// CHECK:STDOUT: !18 = !DILocation(line: 17, column: 18, scope: !17)
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// CHECK:STDOUT: !19 = !DILocation(line: 18, column: 18, scope: !17)
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// CHECK:STDOUT: !20 = !DILocation(line: 19, column: 18, scope: !17)
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// CHECK:STDOUT: !21 = !DILocation(line: 20, column: 18, scope: !17)
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// CHECK:STDOUT: !22 = !DILocation(line: 17, column: 3, scope: !17)
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// CHECK:STDOUT: !23 = !DILocation(line: 18, column: 3, scope: !17)
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// CHECK:STDOUT: !24 = !DILocation(line: 19, column: 3, scope: !17)
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// CHECK:STDOUT: !25 = !DILocation(line: 20, column: 3, scope: !17)
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// CHECK:STDOUT: !26 = !DILocation(line: 16, column: 1, scope: !17)
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// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "PassShort", linkageName: "_CPassShort.Main", scope: null, file: !6, line: 16, type: !18, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
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// CHECK:STDOUT: !18 = !DISubroutineType(types: !19)
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// CHECK:STDOUT: !19 = !{null, !20, !21}
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// CHECK:STDOUT: !20 = !DIBasicType(name: "int", size: 16, encoding: DW_ATE_signed)
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// CHECK:STDOUT: !21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
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// CHECK:STDOUT: !22 = !{!23, !24}
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// CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !17, type: !20)
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// CHECK:STDOUT: !24 = !DILocalVariable(arg: 2, scope: !17, type: !21)
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// CHECK:STDOUT: !25 = !DILocation(line: 17, column: 18, scope: !17)
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// CHECK:STDOUT: !26 = !DILocation(line: 18, column: 18, scope: !17)
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// CHECK:STDOUT: !27 = !DILocation(line: 19, column: 18, scope: !17)
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// CHECK:STDOUT: !28 = !DILocation(line: 20, column: 18, scope: !17)
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// CHECK:STDOUT: !29 = !DILocation(line: 17, column: 3, scope: !17)
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// CHECK:STDOUT: !30 = !DILocation(line: 18, column: 3, scope: !17)
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// CHECK:STDOUT: !31 = !DILocation(line: 19, column: 3, scope: !17)
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// CHECK:STDOUT: !32 = !DILocation(line: 20, column: 3, scope: !17)
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// CHECK:STDOUT: !33 = !DILocation(line: 16, column: 1, scope: !17)
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// CHECK:STDOUT: ; ModuleID = 'import_struct.carbon'
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// CHECK:STDOUT: source_filename = "import_struct.carbon"
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// CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
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@@ -331,7 +338,7 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: !6 = !DIFile(filename: "import_struct.carbon", directory: "")
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// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "Test", linkageName: "_CTest.Main", scope: null, file: !6, line: 6, type: !8, spFlags: DISPFlagDefinition, unit: !5)
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// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
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// CHECK:STDOUT: !9 = !{}
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// CHECK:STDOUT: !9 = !{null}
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// CHECK:STDOUT: !10 = !DILocation(line: 7, column: 3, scope: !7)
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// CHECK:STDOUT: !11 = !DILocation(line: 8, column: 3, scope: !7)
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// CHECK:STDOUT: !12 = !DILocation(line: 9, column: 3, scope: !7)
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@@ -375,8 +382,8 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: ; Function Attrs: nounwind
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// CHECK:STDOUT: define void @_CPassValueExpr.Main(ptr %y) #0 !dbg !20 {
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// CHECK:STDOUT: entry:
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// CHECK:STDOUT: call void @_Z11pass_struct1Y.carbon_thunk(ptr %y), !dbg !21
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// CHECK:STDOUT: ret void, !dbg !22
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// CHECK:STDOUT: call void @_Z11pass_struct1Y.carbon_thunk(ptr %y), !dbg !26
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// CHECK:STDOUT: ret void, !dbg !27
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// CHECK:STDOUT: }
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// CHECK:STDOUT:
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// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
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@@ -418,7 +425,7 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: !6 = !DIFile(filename: "import_class_with_nontrivial_copy.carbon", directory: "")
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// CHECK:STDOUT: !7 = distinct !DISubprogram(name: "PassRefExpr", linkageName: "_CPassRefExpr.Main", scope: null, file: !6, line: 6, type: !8, spFlags: DISPFlagDefinition, unit: !5)
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// CHECK:STDOUT: !8 = !DISubroutineType(types: !9)
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// CHECK:STDOUT: !9 = !{}
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// CHECK:STDOUT: !9 = !{null}
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// CHECK:STDOUT: !10 = !DILocation(line: 7, column: 3, scope: !7)
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// CHECK:STDOUT: !11 = !DILocation(line: 8, column: 3, scope: !7)
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// CHECK:STDOUT: !12 = !DILocation(line: 9, column: 3, scope: !7)
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@@ -429,6 +436,11 @@ fn PassValueExpr(y: Cpp.Y) {
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// CHECK:STDOUT: !17 = !DILocation(line: 17, column: 19, scope: !16)
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// CHECK:STDOUT: !18 = !DILocation(line: 17, column: 3, scope: !16)
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// CHECK:STDOUT: !19 = !DILocation(line: 16, column: 1, scope: !16)
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// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "PassValueExpr", linkageName: "_CPassValueExpr.Main", scope: null, file: !6, line: 20, type: !8, spFlags: DISPFlagDefinition, unit: !5)
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// CHECK:STDOUT: !21 = !DILocation(line: 21, column: 3, scope: !20)
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// CHECK:STDOUT: !22 = !DILocation(line: 20, column: 1, scope: !20)
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// CHECK:STDOUT: !20 = distinct !DISubprogram(name: "PassValueExpr", linkageName: "_CPassValueExpr.Main", scope: null, file: !6, line: 20, type: !21, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !24)
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// CHECK:STDOUT: !21 = !DISubroutineType(types: !22)
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// CHECK:STDOUT: !22 = !{null, !23}
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// CHECK:STDOUT: !23 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 8)
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// CHECK:STDOUT: !24 = !{!25}
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// CHECK:STDOUT: !25 = !DILocalVariable(arg: 1, scope: !20, type: !23)
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// CHECK:STDOUT: !26 = !DILocation(line: 21, column: 3, scope: !20)
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// CHECK:STDOUT: !27 = !DILocation(line: 20, column: 1, scope: !20)
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