[llvm] 9786198 - [LiveDebugVariables] Fix a DBG_VALUE reordering issue (#111124)
David Stenberg via llvm-commits
llvm-commits at lists.llvm.org
Tue Oct 15 02:36:46 PDT 2024
Author: David Stenberg
Date: 2024-10-15T11:36:24+02:00
New Revision: 97861981cccce546b37f56e3e99e68d37c7586c7
URL: https://github.com/llvm/llvm-project/commit/97861981cccce546b37f56e3e99e68d37c7586c7
DIFF: https://github.com/llvm/llvm-project/commit/97861981cccce546b37f56e3e99e68d37c7586c7.diff
LOG: [LiveDebugVariables] Fix a DBG_VALUE reordering issue (#111124)
LDV could reorder reinserted fragment and non-fragment debug values for
the same variable (compared to the input order), potentially resulting
in stale values being presented.
For example, before:
DBG_VALUE 1001, $noreg, !13, !DIExpression(DW_OP_LLVM_fragment, 0, 16)
DBG_VALUE 1002, $noreg, !13, !DIExpression(DW_OP_LLVM_fragment, 16, 16)
DBG_VALUE %0, $noreg, !13, !DIExpression()
After (without this patch):
DBG_VALUE %stack.0, 0, !13, !DIExpression()
DBG_VALUE 1002, $noreg, !13, !DIExpression(DW_OP_LLVM_fragment, 16, 16)
DBG_VALUE 1001, $noreg, !13, !DIExpression(DW_OP_LLVM_fragment, 0, 16)
It would also reorder DBG_VALUEs for different variables. Although that
does not matter for the debug information output, it resulted in some
noise in before/after pass diffs.
This should hopefully align so that instruction referencing and
DBG_VALUE emit debug instructions in the same order (see the
sdag-salvage-add.ll change).
Added:
Modified:
llvm/lib/CodeGen/LiveDebugVariables.cpp
llvm/test/CodeGen/AMDGPU/debug-value2.ll
llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir
llvm/test/DebugInfo/Mips/livedebugvariables-reorder.mir
llvm/test/DebugInfo/X86/live-debug-vars-discard-invalid.mir
llvm/test/DebugInfo/X86/sdag-salvage-add.ll
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 822a1beb489592..2ff346d3fd0223 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -1625,8 +1625,9 @@ findInsertLocation(MachineBasicBlock *MBB, SlotIndex Idx, LiveIntervals &LIS,
}
// Don't insert anything after the first terminator, though.
- return MI->isTerminator() ? MBB->getFirstTerminator() :
- std::next(MachineBasicBlock::iterator(MI));
+ auto It = MI->isTerminator() ? MBB->getFirstTerminator()
+ : std::next(MachineBasicBlock::iterator(MI));
+ return skipDebugInstructionsForward(It, MBB->end());
}
/// Find an iterator for inserting the next DBG_VALUE instruction
diff --git a/llvm/test/CodeGen/AMDGPU/debug-value2.ll b/llvm/test/CodeGen/AMDGPU/debug-value2.ll
index 1d4c11de4076cb..b09d540dd6d7b5 100644
--- a/llvm/test/CodeGen/AMDGPU/debug-value2.ll
+++ b/llvm/test/CodeGen/AMDGPU/debug-value2.ll
@@ -12,11 +12,11 @@ define <4 x float> @Scene_transformT(i32 %subshapeIdx, <4 x float> %v, float %ti
entry:
; CHECK: v_mov_b32_e32 v[[COPIED_ARG_PIECE:[0-9]+]], v9
- ; CHECK: ;DEBUG_VALUE: Scene_transformT:gScene <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 0 32] $vgpr6
+ ; CHECK: ;DEBUG_VALUE: Scene_transformT:gSceneOffsets <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 32 32] $vgpr[[COPIED_ARG_PIECE]]
+ ; CHECK: ;DEBUG_VALUE: Scene_transformT:gSceneOffsets <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 0 32] $vgpr8
; CHECK: ;DEBUG_VALUE: Scene_transformT:gScene <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 32 32] $vgpr7
+ ; CHECK: ;DEBUG_VALUE: Scene_transformT:gScene <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 0 32] $vgpr6
call void @llvm.dbg.value(metadata ptr addrspace(1) %gScene, metadata !120, metadata !DIExpression(DW_OP_constu, 1, DW_OP_swap, DW_OP_xderef)), !dbg !154
- ; CHECK: ;DEBUG_VALUE: Scene_transformT:gSceneOffsets <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 0 32] $vgpr8
- ; CHECK: ;DEBUG_VALUE: Scene_transformT:gSceneOffsets <- [DW_OP_constu 1, DW_OP_swap, DW_OP_xderef, DW_OP_LLVM_fragment 32 32] $vgpr[[COPIED_ARG_PIECE]]
call void @llvm.dbg.value(metadata ptr addrspace(1) %gSceneOffsets, metadata !121, metadata !DIExpression(DW_OP_constu, 1, DW_OP_swap, DW_OP_xderef)), !dbg !155
%call = tail call ptr addrspace(1) @Scene_getSubShapeData(i32 %subshapeIdx, ptr addrspace(1) %gScene, ptr addrspace(1) %gSceneOffsets)
%m_linearMotion = getelementptr inbounds %struct.ShapeData, ptr addrspace(1) %call, i64 0, i32 2
diff --git a/llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir b/llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir
index 5df70096e9305d..d6171ec30b1271 100644
--- a/llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir
+++ b/llvm/test/DebugInfo/MIR/Mips/livedebugvars-stop-trimming-loc.mir
@@ -3,11 +3,13 @@
## This tests that LiveDebugVariables does not trim non-inlined variable
## location.
+# CHECK: ![[VARA:.*]] = !DILocalVariable(name: "a"
# CHECK: ![[VARB:.*]] = !DILocalVariable(name: "b"
# CHECK: ![[VARC:.*]] = !DILocalVariable(name: "c"
# CHECK: $at = COPY $a2
# CHECK-NEXT: DBG_VALUE $at, $noreg, ![[VARC]], !DIExpression(), debug-location
# CHECK: $s0 = COPY $a1
+# CHECK-NEXT: DBG_VALUE $a0, $noreg, ![[VARA]], !DIExpression(), debug-location
# CHECK-NEXT: DBG_VALUE $s0, $noreg, ![[VARB]], !DIExpression(), debug-location
--- |
diff --git a/llvm/test/DebugInfo/Mips/livedebugvariables-reorder.mir b/llvm/test/DebugInfo/Mips/livedebugvariables-reorder.mir
index 6b35af4a738c64..bc24c5272d3187 100644
--- a/llvm/test/DebugInfo/Mips/livedebugvariables-reorder.mir
+++ b/llvm/test/DebugInfo/Mips/livedebugvariables-reorder.mir
@@ -1,21 +1,21 @@
# RUN: llc -emit-call-site-info %s -mtriple=mips -start-before=register-coalescer -stop-after=virtregrewriter -o - | FileCheck %s
-# FIXME: LiveDebugVariables should not reorder the stack location DBG_VALUE and
-# the fragmented DBG_VALUEs for aaa, as the latter may represent a stale value.
-# It should also not reorder the DBG_VALUEs for the
diff erent variables, as
-# that results in noise in pass before/after
diff s.
+# Verify that LiveDebugVariables does not reorder the stack location DBG_VALUE
+# and the fragmented DBG_VALUEs for aaa, as the latter may represent a stale
+# value. It should also not reorder the DBG_VALUEs for the
diff erent variables,
+# as that results in noise in pass before/after
diff s.
# CHECK-DAG: ![[aaa:[0-9]+]] = !DILocalVariable(name: "aaa"
# CHECK-DAG: ![[bbb:[0-9]+]] = !DILocalVariable(name: "bbb"
# CHECK-DAG: ![[ccc:[0-9]+]] = !DILocalVariable(name: "ccc"
# CHECK-DAG: ![[ddd:[0-9]+]] = !DILocalVariable(name: "ddd"
-# CHECK: DBG_VALUE %stack.0, 0, ![[aaa]], !DIExpression()
-# CHECK-NEXT: DBG_VALUE 444, $noreg, ![[ddd]], !DIExpression()
-# CHECK-NEXT: DBG_VALUE 333, $noreg, ![[ccc]], !DIExpression()
-# CHECK-NEXT: DBG_VALUE 222, $noreg, ![[bbb]], !DIExpression()
+# CHECK: DBG_VALUE 1001, $noreg, ![[aaa]], !DIExpression(DW_OP_LLVM_fragment, 0, 16)
# CHECK-NEXT: DBG_VALUE 1002, $noreg, ![[aaa]], !DIExpression(DW_OP_LLVM_fragment, 16, 16)
-# CHECK-NEXT: DBG_VALUE 1001, $noreg, ![[aaa]], !DIExpression(DW_OP_LLVM_fragment, 0, 16)
+# CHECK-NEXT: DBG_VALUE 222, $noreg, ![[bbb]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE 333, $noreg, ![[ccc]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE 444, $noreg, ![[ddd]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE %stack.0, 0, ![[aaa]], !DIExpression()
--- |
target datalayout = "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"
diff --git a/llvm/test/DebugInfo/X86/live-debug-vars-discard-invalid.mir b/llvm/test/DebugInfo/X86/live-debug-vars-discard-invalid.mir
index 08130b47b4c5c9..7c8aa966d3d643 100644
--- a/llvm/test/DebugInfo/X86/live-debug-vars-discard-invalid.mir
+++ b/llvm/test/DebugInfo/X86/live-debug-vars-discard-invalid.mir
@@ -118,15 +118,15 @@ body: |
# CHECK-LABEL: bb.3:
# CHECK: dead renamable $rcx = IMPLICIT_DEF
-# CHECK-NEXT: DBG_VALUE 0, $noreg, !23, !DIExpression()
# CHECK-NEXT: DBG_VALUE $rcx, $noreg, !18, !DIExpression()
+# CHECK-NEXT: DBG_VALUE 0, $noreg, !23, !DIExpression()
# CHECK-LABEL: bb.4:
# CHECK: liveins: $rax
# CHECK: DBG_VALUE $rax, $noreg, !18, !DIExpression()
# CHECK-NEXT: renamable $rax = BTS64ri8 killed renamable $rax, 0, implicit-def $eflags
-# CHECK-NEXT: DBG_VALUE 0, $noreg, !23, !DIExpression()
# CHECK-NEXT: DBG_VALUE $rax, $noreg, !18, !DIExpression()
+# CHECK-NEXT: DBG_VALUE 0, $noreg, !23, !DIExpression()
# CHECK-NEXT: renamable $rax = BTS64ri8 killed renamable $rax, 0, implicit-def $eflags
# CHECK-NEXT: DBG_VALUE $rax, $noreg, !18, !DIExpression()
# CHECK-NEXT: dead renamable $rax = BTS64ri8 killed renamable $rax, 0, implicit-def $eflags
diff --git a/llvm/test/DebugInfo/X86/sdag-salvage-add.ll b/llvm/test/DebugInfo/X86/sdag-salvage-add.ll
index 5a77b9504206cb..bd3ff01f9a8266 100644
--- a/llvm/test/DebugInfo/X86/sdag-salvage-add.ll
+++ b/llvm/test/DebugInfo/X86/sdag-salvage-add.ll
@@ -27,21 +27,18 @@
; instruction selection as it is folded into the load. As a result, we should
; refer to s4 and myVar with complex expressions.
;
-; NB: instruction referencing and DBG_VALUE modes produce debug insts in a
-;
diff erent order.
-;
; CHECK: ![[S4:.*]] = !DILocalVariable(name: "s4",
; CHECK: ![[MYVAR:.*]] = !DILocalVariable(name: "myVar",
; CHECK: $rax = MOV64rm
; INSTRREF-SAME: debug-instr-number 2,
; INSTRREF-NEXT: DBG_INSTR_REF ![[S4]],
-; DBGVALUE-NEXT: DBG_VALUE $rax, $noreg, ![[MYVAR]],
+; DBGVALUE-NEXT: DBG_VALUE $rax, $noreg, ![[S4]],
; DBGVALUE-SAME: !DIExpression(DW_OP_plus_uconst, 4096, DW_OP_stack_value)
; INSTRREF-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_plus_uconst, 4096, DW_OP_stack_value)
; INSTRREF-SAME: dbg-instr-ref(2, 0)
; INSTRREF: DBG_INSTR_REF ![[MYVAR]],
-; DBGVALUE: DBG_VALUE $rax, $noreg, ![[S4]],
+; DBGVALUE: DBG_VALUE $rax, $noreg, ![[MYVAR]],
; DBGVALUE-SAME: !DIExpression(DW_OP_plus_uconst, 4096, DW_OP_stack_value)
; INSTRREF-SAME: !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_plus_uconst, 4096, DW_OP_stack_value)
; INSTRREF-SAME: dbg-instr-ref(2, 0)
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