Author: Jeremy Morse Date: 2022-02-07T13:26:39-08:00 New Revision: 64adff8ec0c14d2184a4a7cfae4bc503ed41bcea
URL: https://github.com/llvm/llvm-project/commit/64adff8ec0c14d2184a4a7cfae4bc503ed41bcea DIFF: https://github.com/llvm/llvm-project/commit/64adff8ec0c14d2184a4a7cfae4bc503ed41bcea.diff LOG: [DebugInfo][InstrRef] Fix a tombstone-in-DenseMap crash from D117877 This is a follow-up to D117877: variable assignments of DBG_VALUE $noreg, or DBG_INSTR_REFs where no value can be found, are represented by a DbgValue object with Kind "Undef", explicitly meaning "there is no value". In D117877 I added a special-case to some assignment accounting faster, without considering this scenario. It causes variables to be given the value ValueIDNum::EmptyValue, which then ends up being a DenseMap key. The DenseMap asserts, because EmptyValue is the tombstone key. Fix this by handling the assign-undef scenario in the special case, to match what happens in the general case: the variable has no value if it's only ever assigned $noreg / undef. Differential Revision: https://reviews.llvm.org/D118715 (cherry picked from commit 43de305704a50983bf134d8fb916f752a02eb076) Added: Modified: llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp llvm/test/DebugInfo/MIR/InstrRef/single-assign-propagation.mir Removed: ################################################################################ diff --git a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp index cc800736a2dc1..3b4d717c9ab4a 100644 --- a/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp +++ b/llvm/lib/CodeGen/LiveDebugValues/InstrRefBasedImpl.cpp @@ -2796,6 +2796,11 @@ void InstrRefBasedLDV::placePHIsForSingleVarDefinition( auto ValueIt = VLocs.Vars.find(Var); const DbgValue &Value = ValueIt->second; + // If it's an explicit assignment of "undef", that means there is no location + // anyway, anywhere. + if (Value.Kind == DbgValue::Undef) + return; + // Assign the variable value to entry to each dominated block that's in scope. // Skip the definition block -- it's assigned the variable value in the middle // of the block somewhere. diff --git a/llvm/test/DebugInfo/MIR/InstrRef/single-assign-propagation.mir b/llvm/test/DebugInfo/MIR/InstrRef/single-assign-propagation.mir index 19408b2ec4291..c247004368837 100644 --- a/llvm/test/DebugInfo/MIR/InstrRef/single-assign-propagation.mir +++ b/llvm/test/DebugInfo/MIR/InstrRef/single-assign-propagation.mir @@ -1,9 +1,11 @@ # RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -o - \ # RUN: -experimental-debug-variable-locations=true \ -# RUN: | FileCheck %s -implicit-check-not=DBG_VALUE +# RUN: | FileCheck %s -implicit-check-not=DBG_VALUE \ +# RUN: --check-prefixes=CHECK,COMMON # RUN: llc %s -march=x86-64 -run-pass=livedebugvalues -o - \ # RUN: -experimental-debug-variable-locations=false \ -# RUN: | FileCheck %s --check-prefixes=VARLOC -implicit-check-not=DBG_VALUE +# RUN: | FileCheck %s -implicit-check-not=DBG_VALUE \ +# RUN: --check-prefixes=VARLOC,COMMON # # This test is designed to stimulate a simplification of variable-value # propagation in InstrRefBasedLDV. When we only have a single assignment of @@ -63,12 +65,23 @@ # VARLOC-LABEL: bb.3: # VARLOC: DBG_VALUE # +## Common tail for 'test2' -- this is checking that the assignment of undef or +## $noreg in single-assignment mode doesn't lead to trouble further down the +## line, specifically assertion failures. +# +# COMMON-LABEL: name: test2 +# COMMON: DBG_VALUE $noreg --- | define i32 @_Z8bb_to_bb() local_unnamed_addr !dbg !12 { entry: ret i32 0, !dbg !17 } + define i32 @test2() local_unnamed_addr !dbg !112 { + entry: + ret i32 0, !dbg !117 + } + !llvm.dbg.cu = !{!0} !llvm.module.flags = !{!7, !8, !9, !10} !llvm.ident = !{!11} @@ -94,6 +107,13 @@ !18 = distinct !DILexicalBlock(scope: !12, file: !1, line: 1, column: 1) !19 = distinct !DILexicalBlock(scope: !12, file: !1, line: 1, column: 1) !20 = !DILocation(line: 10, scope: !19) + !112 = distinct !DISubprogram(name: "test2", linkageName: "102", scope: !1, file: !1, line: 6, type: !13, scopeLine: 6, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !115) + !115 = !{!116} + !116 = !DILocalVariable(name: "myVar", scope: !118, file: !1, line: 7, type: !6) + !117 = !DILocation(line: 10, scope: !118) + !118 = distinct !DILexicalBlock(scope: !112, file: !1, line: 1, column: 1) + !119 = distinct !DILexicalBlock(scope: !112, file: !1, line: 1, column: 1) + !120 = !DILocation(line: 10, scope: !119) ... --- @@ -136,3 +156,44 @@ body: | bb.6: RET 0, debug-location !17 +... +--- +name: test2 +debugValueSubstitutions: + - { srcinst: 4, srcop: 0, dstinst: 3, dstop: 0, subreg: 0 } +body: | + bb.0.entry: + successors: %bb.1, %bb.5, %bb.6 + + $rax = MOV64ri 1, debug-instr-number 1, debug-location !117 + JCC_1 %bb.5, 1, implicit $eflags + JCC_1 %bb.6, 2, implicit $eflags + JMP_1 %bb.1 + + bb.1: + successors: %bb.2, %bb.3 + + DBG_VALUE $noreg, $noreg, !116, !DIExpression(), debug-location !117 + JCC_1 %bb.3, 1, implicit $eflags, debug-location !117 + + bb.2: + successors: %bb.4 + + JMP_1 %bb.4, debug-location !120 + + bb.3: + successors: %bb.4 + + JMP_1 %bb.4, debug-location !117 + + bb.4: + successors: %bb.5, %bb.6 + + JCC_1 %bb.5, 1, implicit $eflags, debug-location !117 + JMP_1 %bb.6, debug-location !117 + + bb.5: + RET 0, debug-location !117 + + bb.6: + RET 0, debug-location !117 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
