llvm-project/llvm/test/DebugInfo/X86/dbg-value-frame-index.ll

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; RUN: llc -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
; RUN: llc -mtriple=x86_64-unknown-unknown -filetype=obj < %s \
; RUN: | llvm-dwarfdump -v - | FileCheck %s --check-prefix=DWARF
define i1 @test() !dbg !4 {
entry:
%end = alloca i64, align 8
br label %while.cond
while.cond:
call void @llvm.dbg.value(metadata i64* %end, metadata !5, metadata !6), !dbg !7
%call = call i1 @fn(i64* %end, i64* %end, i64* null, i8* null, i64 0, i64* null, i32* null, i8* null), !dbg !7
br label %while.body
while.body:
br i1 0, label %while.end, label %while.cond
while.end:
ret i1 true
}
; CHECK-LABEL: test
[DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users LowerDbgDeclare inserts a dbg.value before each use of an address described by a dbg.declare. When inserting a dbg.value before a CallInst use, however, it fails to append DW_OP_deref to the DIExpression. The DW_OP_deref is needed to reflect the fact that a dbg.value describes a source variable directly (as opposed to a dbg.declare, which relies on pointer indirection). This patch adds in the DW_OP_deref where needed. This results in the correct values being shown during a debug session for a program compiled with ASan and optimizations (see https://reviews.llvm.org/D49520). Note that ConvertDebugDeclareToDebugValue is already correct -- no changes there were needed. One complication is that SelectionDAG is unable to distinguish between direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also fixes this long-standing issue in order to not regress integration tests relying on the incorrect assumption that all frame-index SDDbgValues are indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot be lowered properly otherwise. Basically the fix prevents a direct SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice by a debugger. There were a handful of tests relying on this incorrect "FRAMEIX => indirect" assumption which actually had incorrect DW_AT_locations: these are all fixed up in this patch. Testing: - check-llvm, and an end-to-end test using lldb to debug an optimized program. - Existing unit tests for DIExpression::appendToStack fully cover the new DIExpression::append utility. - check-debuginfo (the debug info integration tests) Differential Revision: https://reviews.llvm.org/D49454 llvm-svn: 338069
2018-07-27 04:56:53 +08:00
; To get the value of the variable, we need to do [$rsp+8], i.e:
; CHECK: #DEBUG_VALUE: test:w <- [DW_OP_plus_uconst 8, DW_OP_deref] $rsp
; DWARF: DW_AT_location [DW_FORM_sec_offset] (
; DWARF-NEXT: [{{.*}}, {{.*}}): DW_OP_breg7 RSP+8)
[DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users LowerDbgDeclare inserts a dbg.value before each use of an address described by a dbg.declare. When inserting a dbg.value before a CallInst use, however, it fails to append DW_OP_deref to the DIExpression. The DW_OP_deref is needed to reflect the fact that a dbg.value describes a source variable directly (as opposed to a dbg.declare, which relies on pointer indirection). This patch adds in the DW_OP_deref where needed. This results in the correct values being shown during a debug session for a program compiled with ASan and optimizations (see https://reviews.llvm.org/D49520). Note that ConvertDebugDeclareToDebugValue is already correct -- no changes there were needed. One complication is that SelectionDAG is unable to distinguish between direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also fixes this long-standing issue in order to not regress integration tests relying on the incorrect assumption that all frame-index SDDbgValues are indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot be lowered properly otherwise. Basically the fix prevents a direct SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice by a debugger. There were a handful of tests relying on this incorrect "FRAMEIX => indirect" assumption which actually had incorrect DW_AT_locations: these are all fixed up in this patch. Testing: - check-llvm, and an end-to-end test using lldb to debug an optimized program. - Existing unit tests for DIExpression::appendToStack fully cover the new DIExpression::append utility. - check-debuginfo (the debug info integration tests) Differential Revision: https://reviews.llvm.org/D49454 llvm-svn: 338069
2018-07-27 04:56:53 +08:00
; Note: A previous version of this test checked for `[DW_OP_plus_uconst 8] [$rsp+0]`,
; which is incorrect, because it adds the stack offset after dereferencing the stack pointer.
declare i1 @fn(i64*, i64*, i64*, i8*, i64, i64*, i32*, i8*)
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2,!3}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 4.0.0", emissionKind: FullDebug)
!1 = !DIFile(filename: "test.c", directory: "/")
!2 = !{i32 2, !"Dwarf Version", i32 4}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = distinct !DISubprogram(name: "test", type: !10, unit: !0)
!5 = !DILocalVariable(name: "w", scope: !4, type: !9)
[DebugInfo] LowerDbgDeclare: Add derefs when handling CallInst users LowerDbgDeclare inserts a dbg.value before each use of an address described by a dbg.declare. When inserting a dbg.value before a CallInst use, however, it fails to append DW_OP_deref to the DIExpression. The DW_OP_deref is needed to reflect the fact that a dbg.value describes a source variable directly (as opposed to a dbg.declare, which relies on pointer indirection). This patch adds in the DW_OP_deref where needed. This results in the correct values being shown during a debug session for a program compiled with ASan and optimizations (see https://reviews.llvm.org/D49520). Note that ConvertDebugDeclareToDebugValue is already correct -- no changes there were needed. One complication is that SelectionDAG is unable to distinguish between direct and indirect frame-index (FRAMEIX) SDDbgValues. This patch also fixes this long-standing issue in order to not regress integration tests relying on the incorrect assumption that all frame-index SDDbgValues are indirect. This is a necessary fix: the newly-added DW_OP_derefs cannot be lowered properly otherwise. Basically the fix prevents a direct SDDbgValue with DIExpression(DW_OP_deref) from being dereferenced twice by a debugger. There were a handful of tests relying on this incorrect "FRAMEIX => indirect" assumption which actually had incorrect DW_AT_locations: these are all fixed up in this patch. Testing: - check-llvm, and an end-to-end test using lldb to debug an optimized program. - Existing unit tests for DIExpression::appendToStack fully cover the new DIExpression::append utility. - check-debuginfo (the debug info integration tests) Differential Revision: https://reviews.llvm.org/D49454 llvm-svn: 338069
2018-07-27 04:56:53 +08:00
!6 = !DIExpression(DW_OP_deref)
!7 = !DILocation(line: 210, column: 12, scope: !4)
!8 = !{!9}
!9 = !DIBasicType(name: "bool", size: 8, encoding: DW_ATE_boolean)
!10 = !DISubroutineType(types: !8)