0c5c7b52f0
The CodeView `S_ARMSWITCHTABLE` debug symbol is used to describe the layout of a jump table, it contains the following information:
* The address of the branch instruction that uses the jump table.
* The address of the jump table.
* The "base" address that the values in the jump table are relative to.
* The type of each entry (absolute pointer, a relative integer, a relative integer that is shifted).
Together this information can be used by debuggers and binary analysis tools to understand what an jump table indirect branch is doing and where it might jump to.
Documentation for the symbol can be found in the Microsoft PDB library dumper: 0fe89a942f/cvdump/dumpsym7.cpp (L5518)
This change adds support to LLVM to emit the `S_ARMSWITCHTABLE` debug symbol as well as to dump it out (for testing purposes).
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D149367
73 lines
3.2 KiB
LLVM
73 lines
3.2 KiB
LLVM
; REQUIRES: x86-registered-target
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; RUN: llc < %s | FileCheck %s
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; Repro for issue https://reviews.llvm.org/D149367#4619121
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; Validates that `indirect ptr null` and a jump table can be used in the same function.
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; Verify branch labels match what's in the CodeView
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; CHECK: .Ltmp2:
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; CHECK-NEXT: jmpq *%{{.*}}
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; Verify jump table have the same entry size, base offset and shift as what's in the CodeView
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; CHECK: {{\.?}}LJTI0_0:
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; CHECK-NEXT: .long .LBB0_[[#]]-.LJTI0_0
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; Verify CodeView
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; CHECK: .short 4441 # Record kind: S_ARMSWITCHTABLE
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; CHECK-NEXT: .secrel32 .LJTI0_0 # Base offset
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; CHECK-NEXT: .secidx .LJTI0_0 # Base section index
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; CHECK-NEXT: .short 4 # Switch type
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; CHECK-NEXT: .secrel32 .Ltmp2 # Branch offset
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; CHECK-NEXT: .secrel32 .LJTI0_0 # Table offset
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; CHECK-NEXT: .secidx .Ltmp2 # Branch section index
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; CHECK-NEXT: .secidx .LJTI0_0 # Table section index
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; CHECK-NEXT: .long 4 # Entries count
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; CHECK-NOT: .short 4441 # Record kind: S_ARMSWITCHTABLE
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target datalayout = "e-m:w-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-pc-windows-msvc19.34.0"
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define i32 @f() !dbg !5 {
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entry:
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indirectbr ptr null, [label %BC_SUCCEED], !dbg !11
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BC_SUCCEED: ; preds = %entry
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%0 = lshr i64 0, 0
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switch i64 %0, label %sw.default.i.i2445 [
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i64 3, label %sw.bb15.i.i
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i64 1, label %sw.bb7.i.i
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i64 2, label %sw.bb11.i.i2444
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i64 0, label %sw.bb3.i.i
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]
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sw.bb3.i.i: ; preds = %BC_SUCCEED
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ret i32 0
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sw.bb7.i.i: ; preds = %BC_SUCCEED
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ret i32 0
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sw.bb11.i.i2444: ; preds = %BC_SUCCEED
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ret i32 0
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sw.bb15.i.i: ; preds = %BC_SUCCEED
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ret i32 0
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sw.default.i.i2445: ; preds = %BC_SUCCEED
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ret i32 0
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4}
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!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2, globals: !2, imports: !2, splitDebugInlining: false, nameTableKind: None)
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!1 = !DIFile(filename: "../../v8/src/regexp\\regexp-interpreter.cc", directory: ".", checksumkind: CSK_MD5, checksum: "ddba353f72137fb1d64b5fc8ee071a9c")
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!2 = !{}
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!3 = !{i32 2, !"CodeView", i32 1}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = distinct !DISubprogram(name: "f", linkageName: "f", scope: !7, file: !6, line: 386, type: !10, scopeLine: 391, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !0, templateParams: !2, retainedNodes: !2)
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!6 = !DIFile(filename: "../../v8/src/regexp/regexp-interpreter.cc", directory: ".", checksumkind: CSK_MD5, checksum: "ddba353f72137fb1d64b5fc8ee071a9c")
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!7 = !DINamespace(scope: !8)
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!8 = !DINamespace(name: "internal", scope: !9)
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!9 = !DINamespace(name: "v8", scope: null)
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!10 = distinct !DISubroutineType(types: !2)
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!11 = !DILocation(line: 1, scope: !5) |