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Reland (again): [DWARF] Allow cross-CU references of subprogram definitions This is a revert-of-revert (i.e. this reverts commit 802bec89, which itself reverted fa4701e1 and 79daafc9) with a fix folded in. The problem was that call site tags weren't emitted properly when LTO was enabled along with split-dwarf. This required a minor fix. I've added a reduced test case in test/DebugInfo/X86/fission-call-site.ll. Original commit message: This allows a call site tag in CU A to reference a callee DIE in CU B without resorting to creating an incomplete duplicate DIE for the callee inside of CU A. We already allow cross-CU references of subprogram declarations, so it doesn't seem like definitions ought to be special. This improves entry value evaluation and tail call frame synthesis in the LTO setting. During LTO, it's common for cross-module inlining to produce a call in some CU A where the callee resides in a different CU, and there is no declaration subprogram for the callee anywhere. In this case llvm would (unnecessarily, I think) emit an empty DW_TAG_subprogram in order to fill in the call site tag. That empty 'definition' defeats entry value evaluation etc., because the debugger can't figure out what it means. As a follow-up, maybe we could add a DWARF verifier check that a DW_TAG_subprogram at least has a DW_AT_name attribute. Update #1: Reland with a fix to create a declaration DIE when the declaration is missing from the CU's retainedTypes list. The declaration is left out of the retainedTypes list in two cases: 1) Re-compiling pre-r266445 bitcode (in which declarations weren't added to the retainedTypes list), and 2) Doing LTO function importing (which doesn't update the retainedTypes list). It's possible to handle (1) and (2) by modifying the retainedTypes list (in AutoUpgrade, or in the LTO importing logic resp.), but I don't see an advantage to doing it this way, as it would cause more DWARF to be emitted compared to creating the declaration DIEs lazily. Update #2: Fold in a fix for call site tag emission in the split-dwarf + LTO case. Tested with a stage2 ThinLTO+RelWithDebInfo build of clang, and with a ReleaseLTO-g build of the test suite. rdar://46577651, rdar://57855316, rdar://57840415, rdar://58888440 Differential Revision: https://reviews.llvm.org/D70350
2020-01-26 04:52:47 +08:00
; RUN: llc -mtriple=x86_64-apple-darwin -filetype=obj < %s -o %t.o
; RUN: llvm-dwarfdump %t.o | FileCheck %s -implicit-check-not=DW_TAG_subprogram
; RUN: llvm-dwarfdump --verify %t.o
; This test checks that cross-CU references within call site tags to subprogram
; definitions are well-formed. There are 5 cases checked in this test. Each set
; of checks is numbered and has a brief summary.
; Instructions to regenerate the IR:
; clang -O1 -g -emit-llvm -o a.bc -c a.c
; clang -O1 -g -emit-llvm -o b.bc -c b.c
; llvm-link -o linked.bc a.bc b.bc
; opt -O1 linked.bc -o merged.bc
; Source:
; // a.c
; __attribute__((optnone)) void noinline_func_in_a() {}
;
; __attribute__((optnone)) static void foo() {}
; __attribute__((always_inline)) void always_inline_helper_in_a_that_calls_foo() {
; foo();
; }
;
; extern void func_from_b();
; void call_func_in_b_from_a() {
; func_from_b();
; }
;
; // b.c
; extern void noinline_func_in_a();
; void call_noinline_func_in_a_from_b() {
; noinline_func_in_a();
; }
;
; __attribute__((optnone)) void foo() {}
; extern void always_inline_helper_in_a_that_calls_foo();
; void call_both_foos_from_b() {
; foo();
; always_inline_helper_in_a_that_calls_foo();
; }
;
; __attribute__((optnone)) void func_from_b() {}
; void call_func_in_b_from_b() {
; func_from_b();
; }
; === CU for a.c ===
; CHECK: DW_TAG_compile_unit
; CHECK: DW_AT_name ("a.c")
; CHECK: 0x{{0+}}[[NOINLINE_FUNC_IN_A:.*]]: DW_TAG_subprogram
; CHECK: DW_AT_name ("noinline_func_in_a")
; 1) Check that "always_inline_helper_in_a_that_calls_foo" calls the "foo" in
; a.c, and *not* the "foo" in b.c.
; CHECK: 0x{{0+}}[[ALWAYS_INLINE_HELPER_IN_A:.*]]: DW_TAG_subprogram
; CHECK: DW_AT_abstract_origin ({{.*}} "always_inline_helper_in_a_that_calls_foo")
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_A:.*]])
; CHECK: 0x{{0+}}[[FOO_IN_A]]: DW_TAG_subprogram
; CHECK: DW_AT_name ("foo")
; 2) Check that "call_func_in_b_from_a" has a cross-CU ref into b.c.
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_name ("call_func_in_b_from_a")
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FUNC_FROM_B:.*]])
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_name ("always_inline_helper_in_a_that_calls_foo")
; CHECK: DW_AT_inline (DW_INL_inlined)
; === CU for b.c ===
; CHECK: DW_TAG_compile_unit
; CHECK: DW_AT_name ("b.c")
; 3) Validate the cross-CU ref from "call_func_in_b_from_a" in a.c.
; CHECK: 0x{{0+}}[[FUNC_FROM_B]]: DW_TAG_subprogram
; CHECK: DW_AT_name ("func_from_b")
; 4) Validate the cross-CU ref from "call_noinline_func_in_a_from_b" in b.c.
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_name ("call_noinline_func_in_a_from_b")
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[NOINLINE_FUNC_IN_A]])
; CHECK: 0x{{0+}}[[FOO_IN_B:.*]]: DW_TAG_subprogram
; CHECK: DW_AT_name ("foo")
; 5) Validate that we correctly emit a cross-CU ref when the call is inlined
; from another CU.
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_name ("call_both_foos_from_b")
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_B]])
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FOO_IN_A]])
; CHECK: DW_TAG_subprogram
; CHECK: DW_AT_name ("call_func_in_b_from_b")
; CHECK: DW_TAG_call_site
; CHECK-NEXT: DW_AT_call_origin (0x{{0+}}[[FUNC_FROM_B]])
target datalayout = "e-m:o-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.14.0"
define void @noinline_func_in_a() local_unnamed_addr #0 !dbg !17 {
entry:
ret void, !dbg !20
}
define void @always_inline_helper_in_a_that_calls_foo() local_unnamed_addr #1 !dbg !21 {
entry:
tail call fastcc void @foo.2(), !dbg !22
ret void, !dbg !23
}
define internal fastcc void @foo.2() unnamed_addr #0 !dbg !24 {
entry:
ret void, !dbg !25
}
define void @call_func_in_b_from_a() local_unnamed_addr !dbg !26 {
entry:
tail call void @func_from_b() #3, !dbg !27
ret void, !dbg !28
}
define void @call_noinline_func_in_a_from_b() local_unnamed_addr !dbg !29 {
entry:
tail call void @noinline_func_in_a() #3, !dbg !30
ret void, !dbg !31
}
define void @foo() local_unnamed_addr #0 !dbg !32 {
entry:
ret void, !dbg !33
}
define void @call_both_foos_from_b() local_unnamed_addr !dbg !34 {
entry:
tail call void @foo(), !dbg !35
tail call fastcc void @foo.2() #3, !dbg !36
ret void, !dbg !38
}
define void @func_from_b() local_unnamed_addr #0 !dbg !39 {
entry:
ret void, !dbg !40
}
define void @call_func_in_b_from_b() local_unnamed_addr !dbg !41 {
entry:
tail call void @func_from_b(), !dbg !42
ret void, !dbg !43
}
attributes #0 = { noinline }
attributes #1 = { alwaysinline }
!llvm.dbg.cu = !{!0, !7}
!llvm.ident = !{!12, !12}
!llvm.module.flags = !{!13, !14, !15, !16}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !3, nameTableKind: None)
!1 = !DIFile(filename: "a.c", directory: "/Users/vsk/tmp/lto-entry-vals")
!2 = !{}
!3 = !{!4}
!4 = !DISubprogram(name: "func_from_b", scope: !1, file: !1, line: 8, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
!5 = !DISubroutineType(types: !6)
!6 = !{null, null}
!7 = distinct !DICompileUnit(language: DW_LANG_C99, file: !8, producer: "clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !9, nameTableKind: None)
!8 = !DIFile(filename: "b.c", directory: "/Users/vsk/tmp/lto-entry-vals")
!9 = !{!10, !11}
!10 = !DISubprogram(name: "noinline_func_in_a", scope: !8, file: !8, line: 1, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
!11 = !DISubprogram(name: "always_inline_helper_in_a_that_calls_foo", scope: !8, file: !8, line: 7, type: !5, spFlags: DISPFlagOptimized, retainedNodes: !2)
!12 = !{!"clang version 10.0.0 (git@github.com:llvm/llvm-project.git 310e85309f870ee7347ef979d7d8da9bf28e92ea)"}
!13 = !{i32 7, !"Dwarf Version", i32 4}
!14 = !{i32 2, !"Debug Info Version", i32 3}
!15 = !{i32 1, !"wchar_size", i32 4}
!16 = !{i32 7, !"PIC Level", i32 2}
!17 = distinct !DISubprogram(name: "noinline_func_in_a", scope: !1, file: !1, line: 1, type: !18, scopeLine: 1, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
!18 = !DISubroutineType(types: !19)
!19 = !{null}
!20 = !DILocation(line: 1, column: 53, scope: !17)
!21 = distinct !DISubprogram(name: "always_inline_helper_in_a_that_calls_foo", scope: !1, file: !1, line: 4, type: !18, scopeLine: 4, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
!22 = !DILocation(line: 5, column: 3, scope: !21)
!23 = !DILocation(line: 6, column: 1, scope: !21)
!24 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !18, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
!25 = !DILocation(line: 3, column: 45, scope: !24)
!26 = distinct !DISubprogram(name: "call_func_in_b_from_a", scope: !1, file: !1, line: 9, type: !18, scopeLine: 9, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2)
!27 = !DILocation(line: 10, column: 3, scope: !26)
!28 = !DILocation(line: 11, column: 1, scope: !26)
!29 = distinct !DISubprogram(name: "call_noinline_func_in_a_from_b", scope: !8, file: !8, line: 2, type: !18, scopeLine: 2, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
!30 = !DILocation(line: 3, column: 3, scope: !29)
!31 = !DILocation(line: 4, column: 1, scope: !29)
!32 = distinct !DISubprogram(name: "foo", scope: !8, file: !8, line: 6, type: !18, scopeLine: 6, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
!33 = !DILocation(line: 6, column: 38, scope: !32)
!34 = distinct !DISubprogram(name: "call_both_foos_from_b", scope: !8, file: !8, line: 8, type: !18, scopeLine: 8, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
!35 = !DILocation(line: 9, column: 3, scope: !34)
!36 = !DILocation(line: 5, column: 3, scope: !21, inlinedAt: !37)
!37 = distinct !DILocation(line: 10, column: 3, scope: !34)
!38 = !DILocation(line: 11, column: 1, scope: !34)
!39 = distinct !DISubprogram(name: "func_from_b", scope: !8, file: !8, line: 13, type: !18, scopeLine: 13, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
!40 = !DILocation(line: 13, column: 46, scope: !39)
!41 = distinct !DISubprogram(name: "call_func_in_b_from_b", scope: !8, file: !8, line: 14, type: !18, scopeLine: 14, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !7, retainedNodes: !2)
!42 = !DILocation(line: 15, column: 3, scope: !41)
!43 = !DILocation(line: 16, column: 1, scope: !41)