[llvm] r370334 - [DebugInfo] LiveDebugValues: correctly discriminate kinds of variable locations
Jeremy Morse via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 29 04:20:54 PDT 2019
Author: jmorse
Date: Thu Aug 29 04:20:54 2019
New Revision: 370334
URL: http://llvm.org/viewvc/llvm-project?rev=370334&view=rev
Log:
[DebugInfo] LiveDebugValues: correctly discriminate kinds of variable locations
The missing line added by this patch ensures that only spilt variable
locations are candidates for being restored from the stack. Otherwise,
register or constant-value information can be interpreted as a spill
location, through a union.
The added regression test replicates a scenario where this occurs: the
stack load from [rsp] causes the register-location DBG_VALUE to be
"restored" to rsi, when it should be left alone. See PR43058 for details.
Un x-fail a test that was suffering from this from a previous patch.
Differential Revision: https://reviews.llvm.org/D66895
Added:
llvm/trunk/test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir
Modified:
llvm/trunk/lib/CodeGen/LiveDebugValues.cpp
llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll
Modified: llvm/trunk/lib/CodeGen/LiveDebugValues.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveDebugValues.cpp?rev=370334&r1=370333&r2=370334&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveDebugValues.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveDebugValues.cpp Thu Aug 29 04:20:54 2019
@@ -875,6 +875,7 @@ void LiveDebugValues::transferSpillOrRes
LLVM_DEBUG(dbgs() << "Spilling Register " << printReg(Reg, TRI) << '('
<< VarLocIDs[ID].Var.getVar()->getName() << ")\n");
} else if (TKind == TransferKind::TransferRestore &&
+ VarLocIDs[ID].Kind == VarLoc::SpillLocKind &&
VarLocIDs[ID].Loc.SpillLocation == *Loc) {
LLVM_DEBUG(dbgs() << "Restoring Register " << printReg(Reg, TRI) << '('
<< VarLocIDs[ID].Var.getVar()->getName() << ")\n");
Modified: llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll?rev=370334&r1=370333&r2=370334&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/debug-info-blocks.ll Thu Aug 29 04:20:54 2019
@@ -1,8 +1,5 @@
; RUN: llc -filetype=obj -O0 < %s | llvm-dwarfdump -v - | FileCheck %s
-; XFAIL: *
-; PR43058
-
; debug_info content
; CHECK: DW_AT_name {{.*}} "foobar_func_block_invoke_0"
; CHECK-NOT: DW_TAG_subprogram
Added: llvm/trunk/test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir?rev=370334&view=auto
==============================================================================
--- llvm/trunk/test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir (added)
+++ llvm/trunk/test/DebugInfo/MIR/X86/live-debug-values-restore-collide.mir Thu Aug 29 04:20:54 2019
@@ -0,0 +1,85 @@
+# RUN: llc %s -o - -run-pass=livedebugvalues -mtriple=x86_64-unknown-unknown | FileCheck %s
+#
+# This is a regression test for register/stack variable locations being
+# interpreted as each other. We place a variable location on the stack, based
+# on $rsp. We later make a memory load from $rsp. On faulty versions of LLVM
+# this gets interpreted as a stack restore of the spilt value (it's not).
+#
+# Test that LiveDebugValues does not create any new variable locations.
+#
+# CHECK-LABEL: name: baaar
+# CHECK-LABEL: bb.0.entry:
+# CHECK: DBG_VALUE $r9d, $noreg, !{{[0-9]*}}, !DIExpression()
+# CHECK: DBG_VALUE $rsp, 0, !{{[0-9]*}}, !DIExpression(DW_OP_plus_uconst, 16)
+# CHECK-NOT: DBG_VALUE
+--- |
+ target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+ target triple = "x86_64-unknown-linux-gnu"
+
+ define void @baaar() !dbg !4 {
+ entry:
+ ret void
+ }
+
+ !llvm.module.flags = !{!0, !1}
+ !llvm.dbg.cu = !{!2}
+
+ !0 = !{i32 2, !"Debug Info Version", i32 3}
+ !1 = !{i32 2, !"Dwarf Version", i32 4}
+ !2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+ !3 = !DIFile(filename: "sheep.cpp", directory: ".")
+ !4 = distinct !DISubprogram(name: "baaar", scope: !3, file: !3, line: 1, type: !5, spFlags: DISPFlagDefinition, unit: !2, retainedNodes: !8)
+ !5 = !DISubroutineType(types: !6)
+ !6 = !{!7}
+ !7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+ !8 = !{!9}
+ !9 = !DILocalVariable(name: "moo", scope: !4, file: !3, line: 1, type: !7)
+ !10 = !DILocation(line: 1, scope: !4)
+
+...
+---
+name: baaar
+alignment: 4
+tracksRegLiveness: true
+liveins:
+ - { reg: '$rdi', virtual-reg: '' }
+ - { reg: '$rsi', virtual-reg: '' }
+ - { reg: '$rdx', virtual-reg: '' }
+ - { reg: '$rcx', virtual-reg: '' }
+ - { reg: '$r8', virtual-reg: '' }
+ - { reg: '$r9d', virtual-reg: '' }
+frameInfo:
+ stackSize: 24
+ offsetAdjustment: -24
+ maxAlignment: 8
+ adjustsStack: true
+ hasCalls: true
+fixedStack:
+stack:
+ - { id: 0, name: '', type: spill-slot, offset: -16, size: 8, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+ - { id: 1, name: '', type: spill-slot, offset: -32, size: 8, alignment: 8,
+ stack-id: default, callee-saved-register: '', callee-saved-restored: true,
+ debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
+body: |
+ bb.0.entry:
+ liveins: $rcx, $rdi, $rdx, $rsi, $r8, $r9d, $rbp, $r15, $r14, $r13, $r12, $rbx
+
+ ; Setup
+ DBG_VALUE $r9d, $noreg, !9, !DIExpression(), debug-location !10
+ $rsp = frame-setup SUB64ri8 $rsp, 24, implicit-def dead $eflags
+
+ ; Spill
+ MOV32mr $rsp, 1, $noreg, 16, $noreg, $r9d :: (store 4 into %stack.0)
+ DBG_VALUE $rsp, 0, !9, !DIExpression(DW_OP_plus_uconst, 16), debug-location !10
+
+ ; This load from the stack can be misinterpreted as a stack restore of
+ ; any DBG_VALUe pointing at $rsp.
+ $rsi = MOV64rm $rsp, 1, $noreg, 0, $noreg :: (load 8 from %stack.1)
+
+ ; Return faff
+ $eax = MOV32ri 0
+ $rsp = frame-destroy ADD64ri8 $rsp, 24, implicit-def dead $eflags
+ RETQ debug-location !10
+...
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