[DebugInfo][InstrRef] Describe value sizes when spilt to stack

InstrRefBasedLDV can track and describe variable values that are spilt to
the stack -- however it does not current describe the size of the value on
the stack. This can cause uninitialized bytes to be read from the stack if
a small register is spilt for a larger variable, or theoretically on
big-endian machines if a large value on the stack is used for a small
variable.

Fix this by using DW_OP_deref_size to specify the amount of data to load
from the stack, if there's any possibility for ambiguity. There are a few
scenarios where this can be omitted (such as when using DW_OP_piece and a
non-DW_OP_stack_value location), see deref-spills-with-size.mir for an
explicit table of inputs flavours and output expressions.

Differential Revision: https://reviews.llvm.org/D123599
This commit is contained in:
Jeremy Morse 2022-04-27 09:40:31 +01:00
parent 4a8c13a6f4
commit a15b66e76d
5 changed files with 449 additions and 19 deletions

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@ -870,19 +870,70 @@ MachineInstrBuilder MLocTracker::emitLoc(Optional<LocIdx> MLoc,
// the variable is.
if (Offset == 0) {
const SpillLoc &Spill = SpillLocs[SpillID.id()];
Expr = TRI.prependOffsetExpression(Expr, DIExpression::ApplyOffset,
Spill.SpillOffset);
unsigned Base = Spill.SpillBase;
MIB.addReg(Base);
MIB.addImm(0);
// Being on the stack makes this location indirect; if it was _already_
// indirect though, we need to add extra indirection. See this test for
// a scenario where this happens:
// llvm/test/DebugInfo/X86/spill-nontrivial-param.ll
// There are several ways we can dereference things, and several inputs
// to consider:
// * NRVO variables will appear with IsIndirect set, but should have
// nothing else in their DIExpressions,
// * Variables with DW_OP_stack_value in their expr already need an
// explicit dereference of the stack location,
// * Values that don't match the variable size need DW_OP_deref_size,
// * Everything else can just become a simple location expression.
// We need to use deref_size whenever there's a mismatch between the
// size of value and the size of variable portion being read.
// Additionally, we should use it whenever dealing with stack_value
// fragments, to avoid the consumer having to determine the deref size
// from DW_OP_piece.
bool UseDerefSize = false;
unsigned ValueSizeInBits = getLocSizeInBits(*MLoc);
unsigned DerefSizeInBytes = ValueSizeInBits / 8;
if (auto Fragment = Var.getFragment()) {
unsigned VariableSizeInBits = Fragment->SizeInBits;
if (VariableSizeInBits != ValueSizeInBits || Expr->isComplex())
UseDerefSize = true;
} else if (auto Size = Var.getVariable()->getSizeInBits()) {
if (*Size != ValueSizeInBits) {
UseDerefSize = true;
}
}
if (Properties.Indirect) {
std::vector<uint64_t> Elts = {dwarf::DW_OP_deref};
Expr = DIExpression::append(Expr, Elts);
// This is something like an NRVO variable, where the pointer has been
// spilt to the stack. It should end up being a memory location, with
// the pointer to the variable loaded off the stack with a deref:
assert(!Expr->isComplex());
Expr = TRI.prependOffsetExpression(
Expr, DIExpression::ApplyOffset | DIExpression::DerefAfter,
Spill.SpillOffset);
MIB.addImm(0);
} else if (UseDerefSize) {
// We're loading a value off the stack that's not the same size as the
// variable. Add / subtract stack offset, explicitly deref with a size,
// and add DW_OP_stack_value if not already present.
SmallVector<uint64_t, 2> Ops = {dwarf::DW_OP_deref_size,
DerefSizeInBytes};
Expr = DIExpression::prependOpcodes(Expr, Ops, true);
unsigned Flags = DIExpression::StackValue | DIExpression::ApplyOffset;
Expr = TRI.prependOffsetExpression(Expr, Flags, Spill.SpillOffset);
MIB.addReg(0);
} else if (Expr->isComplex()) {
// A variable with no size ambiguity, but with extra elements in it's
// expression. Manually dereference the stack location.
assert(Expr->isComplex());
Expr = TRI.prependOffsetExpression(
Expr, DIExpression::ApplyOffset | DIExpression::DerefAfter,
Spill.SpillOffset);
MIB.addReg(0);
} else {
// A plain value that has been spilt to the stack, with no further
// context. Request a location expression, marking the DBG_VALUE as
// IsIndirect.
Expr = TRI.prependOffsetExpression(Expr, DIExpression::ApplyOffset,
Spill.SpillOffset);
MIB.addImm(0);
}
} else {
// This is a stack location with a weird subregister offset: emit an undef

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@ -633,6 +633,19 @@ public:
/// Return true if Idx is a spill machine location.
bool isSpill(LocIdx Idx) const { return LocIdxToLocID[Idx] >= NumRegs; }
/// How large is this location (aka, how wide is a value defined there?).
unsigned getLocSizeInBits(LocIdx L) const {
unsigned ID = LocIdxToLocID[L];
if (!isSpill(L)) {
return TRI.getRegSizeInBits(Register(ID), MF.getRegInfo());
} else {
// The slot location on the stack is uninteresting, we care about the
// position of the value within the slot (which comes with a size).
StackSlotPos Pos = locIDToSpillIdx(ID);
return Pos.first;
}
}
MLocIterator begin() { return MLocIterator(LocIdxToIDNum, 0); }
MLocIterator end() {

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@ -0,0 +1,371 @@
# RUN: llc %s -o - -experimental-debug-variable-locations=true \
# RUN: -run-pass=livedebugvalues \
# RUN: | FileCheck %s --implicit-check-not=DBG_VALUE
# RUN: llc %s -o - -experimental-debug-variable-locations=true \
# RUN: -start-before=livedebugvalues -filetype=obj \
# RUN: | llvm-dwarfdump - | FileCheck %s --check-prefix=DWARF
#
# LLVM can produce DIExpressions that convert from one value of arbitrary size
# to another. This is normally fine, however that means the value for a
# variable tracked in instruction referencing might not be the same size as the
# variable itself.
#
# This becomes a problem when values move onto the stack and we emit
# DW_OP_deref: there is no information about how large a value the consumer
# should load from the stack. The convention today appears to be the size of
# the variable, and as a result if you have a value that's smaller than the
# variable size, extra information is loaded onto the DWARF expression stack.
# This then appears as a false variable value to the consumer.
#
# In this test, there are various scenarios to test where the size of the value
# needs to reach the expression emitter in LiveDebugValues. However, there are
# even more scenarios to consider where the value is in a spill slot, and:
# * The value is larger than the variable, the same, or smaller,
# * The variable is a normal scalar, or a fragment,
# * There is a DW_OP_stack_value in the expression, or not
# That gives us twelve situations to consider, and the easiest way to confirm
# correctness is to write them all out. The final DWARF expressions to
# produce are:
# * No stack value,
# * Scalar (32 bits),
# * Larger value (64 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value
# * Same value (32 bits)
# DW_OP_breg7 RSP-8
# * Smaller value (8 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
# * Fragment (32 bits)
# * Larger value (64 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value, DW_OP_piece 0x4
# * Same value (32 bits)
# DW_OP_breg7 RSP-8, DW_OP_piece 0x4
# * Smaller value (8 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value, DW_OP_piece 0x4
# * Stack value (imagine there was some arithmetic on the stack before the
# DW_OP_stack_value opcode),
# * Scalar (32 bits),
# * Larger value (64 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value
# * Same value (32 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_stack_value
# * Smaller value (8 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
# * Fragment (32 bits)
# * Larger value (64 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value, DW_OP_piece 0x4
# * Same value (32 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_stack_value, DW_OP_piece 0x4
# * Smaller value (8 bits)
# DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value, DW_OP_piece 0x4
#
# The outlier from the pattern is (Stack value, Fragment, Same value size): we
# put a DW_OP_deref_size in where a DW_OP_deref could have sufficied. However,
# if we used DW_OP_deref, it would force the consumer to derive the deref size
# from the DW_OP_piece, which is un-necessarily hard.
## Capture variable num,
# CHECK-DAG: ![[VARNUM:[0-9]+]] = !DILocalVariable(name: "flannel",
# CHECK-DAG: ![[VARNUM2:[0-9]+]] = !DILocalVariable(name: "shoes",
# DWARF: DW_TAG_variable
# DWARF-NEXT: DW_AT_location
## Defined in register, spilt to stack.
# DWARF-NEXT: DW_OP_breg0 RAX+0, DW_OP_constu 0xff, DW_OP_and, DW_OP_convert (0x00000026) "DW_ATE_signed_8", DW_OP_convert (0x0000002a) "DW_ATE_signed_32", DW_OP_stack_value
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_convert (0x00000026) "DW_ATE_signed_8", DW_OP_convert (0x0000002a) "DW_ATE_signed_32", DW_OP_stack_value
## Defined on stack.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_convert (0x00000026) "DW_ATE_signed_8", DW_OP_convert (0x0000002a) "DW_ATE_signed_32", DW_OP_stack_value
## DBG_PHI that moves to stack.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
## DBG_PHI of stack with size.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x2, DW_OP_stack_value
## Followed by scalar / no-stack-value locations with various sizes.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value
# DWARF-NEXT: DW_OP_breg7 RSP-8
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value
## scalar / stack value with various sizes.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value)
# DWARF: DW_AT_name ("flannel")
# Variable with fragments.
# DWARF: DW_TAG_variable
# DWARF-NEXT: DW_AT_location
## Scalar / no-stack-value locations with various sizes.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_stack_value, DW_OP_piece 0x4
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_piece 0x4
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_stack_value, DW_OP_piece 0x4
## Scalar / stack value with various sizes.
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x8, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x4, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4
# DWARF-NEXT: DW_OP_breg7 RSP-8, DW_OP_deref_size 0x1, DW_OP_lit1, DW_OP_plus, DW_OP_stack_value, DW_OP_piece 0x4)
# DWARF: DW_AT_name ("shoes")
--- |
; ModuleID = 'missingvar.ll'
source_filename = "a"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define linkonce_odr void @_ZNSt5dequeIPN4llvm4LoopESaIS2_EE13_M_insert_auxESt15_Deque_iteratorIS2_RS2_PS2_EmRKS2_() local_unnamed_addr align 2 !dbg !3 {
entry:
call void @llvm.dbg.value(metadata i32 0, metadata !8, metadata !DIExpression()), !dbg !7
call void @llvm.dbg.value(metadata i32 0, metadata !10, metadata !DIExpression()), !dbg !7
ret void
}
declare void @llvm.dbg.value(metadata, metadata, metadata)
!llvm.module.flags = !{!0, !9}
!llvm.dbg.cu = !{!1}
!0 = !{i32 2, !"Debug Info Version", i32 3}
!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "beards", isOptimized: true, runtimeVersion: 4, emissionKind: FullDebug)
!2 = !DIFile(filename: "bees.cpp", directory: "")
!3 = distinct !DISubprogram(name: "nope", scope: !2, file: !2, line: 1, type: !4, spFlags: DISPFlagDefinition, unit: !1)
!4 = !DISubroutineType(types: !5)
!5 = !{!6}
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!7 = !DILocation(line: 1, scope: !3)
!8 = !DILocalVariable(name: "flannel", scope: !3, type: !6)
!9 = !{i32 2, !"Dwarf Version", i32 5}
!10 = !DILocalVariable(name: "shoes", scope: !3, type: !11)
!11 = !DIBasicType(name: "long", size: 64, encoding: DW_ATE_signed)
...
---
name: _ZNSt5dequeIPN4llvm4LoopESaIS2_EE13_M_insert_auxESt15_Deque_iteratorIS2_RS2_PS2_EmRKS2_
alignment: 16
tracksRegLiveness: true
liveins:
- { reg: '$rdi' }
- { reg: '$rsi' }
- { reg: '$rdx' }
frameInfo:
stackSize: 48
offsetAdjustment: -48
maxAlignment: 8
maxCallFrameSize: 0
cvBytesOfCalleeSavedRegisters: 48
fixedStack:
- { id: 0, type: spill-slot, offset: -56, size: 8, alignment: 8, callee-saved-register: '$rbx' }
- { id: 1, type: spill-slot, offset: -48, size: 8, alignment: 16, callee-saved-register: '$r12' }
- { id: 2, type: spill-slot, offset: -40, size: 8, alignment: 8, callee-saved-register: '$r13' }
- { id: 3, type: spill-slot, offset: -32, size: 8, alignment: 16, callee-saved-register: '$r14' }
- { id: 4, type: spill-slot, offset: -24, size: 8, alignment: 8, callee-saved-register: '$r15' }
- { id: 5, type: spill-slot, offset: -16, size: 8, alignment: 16, callee-saved-register: '$rbp' }
stack:
- { id: 0, type: spill-slot, offset: -64, size: 8, alignment: 8 }
machineFunctionInfo: {}
body: |
bb.0.entry:
liveins: $rdi, $rdx, $rsi, $rbp, $r15, $r14, $r13, $r12, $rbx
; CHECK-LABEL: bb.0.entry:
;; PART ONE: For this first block of tests, check that information about
;; the size of the value on the stack makes it through to the expression.
$al = MOV8ri 0, debug-instr-number 1, debug-location !7
DBG_INSTR_REF 1, 0, !8, !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value), debug-location !7
; CHECK: DBG_VALUE $al, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed,
; CHECK-SAME : DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)
MOV8mr $rsp, 1, $noreg, -8, $noreg, renamable $al :: (store 1 into %stack.0)
;; Clobber to force variable location onto stack. We should use a
;; deref_size 1 because the value is smaller than the variable.
$al = MOV8ri 0, debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus,
; CHECK-SAME: DW_OP_deref_size, 1, DW_OP_LLVM_convert, 8, DW_ATE_signed,
; CHECK-SAME: DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value),
; Terminate the current variable location,
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg, ![[VARNUM]], !DIExpression()
;; Try again, but with the value originating on the stack, to ensure that
;; we can find its size. It should be deref_size 1 again.
INC8m $rsp, 1, $noreg, 4, $noreg, implicit-def dead $eflags, debug-instr-number 2, debug-location !7 :: (store (s8) into %stack.0)
DBG_INSTR_REF 2, 1000000, !8, !DIExpression(DW_OP_LLVM_convert, 8, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus,
; CHECK-SAME: DW_OP_deref_size, 1, DW_OP_LLVM_convert, 8, DW_ATE_signed,
; CHECK-SAME: DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
;; How about DBG_PHIs? The size of the value is communicated by the register
;; size, or an extra DBG_PHI operand, and that should feed through into the
;; decision of whether to deref_size or not.
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg
$al = MOV8ri 0, debug-location !7
DBG_PHI $al, 7
MOV32mr $rsp, 1, $noreg, -8, $noreg, renamable $eax :: (store 4 into %stack.0)
$eax = MOV32ri 0, debug-location !7
DBG_INSTR_REF 7, 0, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_stack_value)
$eax = MOV32ri 0, debug-location !7
;; And for when the DBG_PHI specifies a stack size...
DBG_PHI %stack.0, 8, 16
DBG_INSTR_REF 8, 0, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 2, DW_OP_stack_value)
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; PART TWO: test the twelve kinds of location expression mentioned in the
;; opening comment of this test, in that order. Please update the opening
;; comment, these lines and the DWARF check lines at the same time.
;; In each test we'll state a location, give it an instruction to cover,
;; and then terminate it.
;; Scalar (32), Large value (64), no stack value,
$rax = MOV64ri 0, debug-instr-number 10, debug-location !7
MOV64mr $rsp, 1, $noreg, -8, $noreg, renamable $rax :: (store 8 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 10, 0, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Scalar (32), Same value size (32), no stack value,
$eax = MOV32ri 0, debug-instr-number 11, debug-location !7
MOV32mr $rsp, 1, $noreg, -8, $noreg, renamable $eax :: (store 4 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 11, 0, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Scalar (32), Smaller value (8), no stack value,
$al = MOV8ri 0, debug-instr-number 12, debug-location !7
MOV8mr $rsp, 1, $noreg, -8, $noreg, renamable $al :: (store 1 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 12, 0, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Larger value (64), no stack value,
$rax = MOV64ri 0, debug-instr-number 13, debug-location !7
MOV64mr $rsp, 1, $noreg, -8, $noreg, renamable $rax :: (store 8 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 13, 0, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Same value size (32), no stack value,
$eax = MOV32ri 0, debug-instr-number 14, debug-location !7
MOV32mr $rsp, 1, $noreg, -8, $noreg, renamable $eax :: (store 4 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 14, 0, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, 0, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Smaller value (8), no stack value,
$al = MOV8ri 0, debug-instr-number 15, debug-location !7
MOV8mr $rsp, 1, $noreg, -8, $noreg, renamable $al :: (store 1 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 15, 0, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Scalar (32), Large value (64), with stack value,
$rax = MOV64ri 0, debug-instr-number 16, debug-location !7
MOV64mr $rsp, 1, $noreg, -8, $noreg, renamable $rax :: (store 8 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 16, 0, !8, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Scalar (32), Same value size (32), no stack value,
$eax = MOV32ri 0, debug-instr-number 17, debug-location !7
MOV32mr $rsp, 1, $noreg, -8, $noreg, renamable $eax :: (store 4 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 17, 0, !8, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Scalar (32), Smaller value (8), no stack value,
$al = MOV8ri 0, debug-instr-number 18, debug-location !7
MOV8mr $rsp, 1, $noreg, -8, $noreg, renamable $al :: (store 1 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 18, 0, !8, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !8, !DIExpression(), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Larger value (64), no stack value,
$rax = MOV64ri 0, debug-instr-number 19, debug-location !7
MOV64mr $rsp, 1, $noreg, -8, $noreg, renamable $rax :: (store 8 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 19, 0, !10, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 8, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Same value size (32), no stack value,
$eax = MOV32ri 0, debug-instr-number 20, debug-location !7
MOV32mr $rsp, 1, $noreg, -8, $noreg, renamable $eax :: (store 4 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 20, 0, !10, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 4, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
;; Fragment (32), Smaller value (8), no stack value,
$al = MOV8ri 0, debug-instr-number 21, debug-location !7
MOV8mr $rsp, 1, $noreg, -8, $noreg, renamable $al :: (store 1 into %stack.0)
$rax = MOV64ri 0, debug-location !7
DBG_INSTR_REF 21, 0, !10, !DIExpression(DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $rsp, $noreg, ![[VARNUM2]],
; CHECK-SAME: !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref_size, 1, DW_OP_constu, 1, DW_OP_plus, DW_OP_stack_value, DW_OP_LLVM_fragment, 0, 32),
$eax = MOV32ri 0, debug-location !7
DBG_VALUE $noreg, $noreg, !10, !DIExpression(DW_OP_LLVM_fragment, 0, 32), debug-location !7
; CHECK: DBG_VALUE $noreg, $noreg
RET64 0, debug-location !7
...

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@ -414,15 +414,12 @@ body: |
# This third function tests that complex expressions are spilt, and restored
# correctly within a basic block.
# FIXME: the spilt location below is wrong, there should be a deref between
# the spill-offset and the DW_OP_plus_uconst.
# CHECK-LABEL: name: h
# CHECK-LABEL: bb.0.entry:
# CHECK: DBG_VALUE $rdi, $noreg, ![[RVAR]], !DIExpression(DW_OP_plus_uconst, 1)
# CHECK-LABEL: bb.1.if.then:
# CHECK: DBG_VALUE $rdi, $noreg, ![[RVAR]], !DIExpression(DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, 0, ![[RVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, $noreg, ![[RVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rdi, $noreg, ![[RVAR]], !DIExpression(DW_OP_plus_uconst, 1)
# CHECK-LABEL: bb.2.if.end:
# CHECK: DBG_VALUE $rdi, $noreg, ![[RVAR]], !DIExpression(DW_OP_plus_uconst, 1)
@ -527,8 +524,6 @@ body: |
# bb 2 and 3, neither of which modifies the stack loc. The exit block (3)
# should still be tracking the spill, and restore it on stack load.
# FIXME: this test too contains a broken spill location.
# Summary: loc is in $rdi in bb0, spills to stack in bb1, remains in stack
# in bb2, starts in stack then loaded in bb3.
@ -537,11 +532,11 @@ body: |
# CHECK: DBG_VALUE $rdi, $noreg, ![[SVAR]], !DIExpression(DW_OP_plus_uconst, 1)
# CHECK-LABEL: bb.1.foo:
# CHECK: DBG_VALUE $rdi, $noreg, ![[SVAR]], !DIExpression(DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, 0, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, $noreg, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1)
# CHECK-LABEL: bb.2.if.then:
# CHECK: DBG_VALUE $rsp, 0, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, $noreg, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1)
# CHECK-LABEL: bb.3.if.end
# CHECK: DBG_VALUE $rsp, 0, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rsp, $noreg, ![[SVAR]], !DIExpression(DW_OP_constu, 8, DW_OP_minus, DW_OP_deref, DW_OP_plus_uconst, 1)
# CHECK: DBG_VALUE $rdi, $noreg, ![[SVAR]], !DIExpression(DW_OP_plus_uconst, 1)
name: i
alignment: 16

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@ -52,7 +52,7 @@
!3 = !{!4}
!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
!5 = distinct !DIGlobalVariable(name: "start", scope: !0, file: !1, line: 4, type: !6, isLocal: false, isDefinition: true)
!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!6 = !DIBasicType(name: "int", size: 64, encoding: DW_ATE_signed)
!7 = !{i32 2, !"Dwarf Version", i32 4}
!8 = !{i32 2, !"Debug Info Version", i32 3}
!9 = !{i32 1, !"wchar_size", i32 2}