From: Bjorn Pettersson Date: Fri, 25 Oct 2019 17:03:18 +0000 (+0200) Subject: [LDV][RAGreedy] Inform LiveDebugVariables about new VRegs added by InlineSpiller X-Git-Tag: llvmorg-11-init~5248 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=56c22931bdfafe8257e610cb9f29b9d64478f812;p=platform%2Fupstream%2Fllvm.git [LDV][RAGreedy] Inform LiveDebugVariables about new VRegs added by InlineSpiller Summary: Make sure RAGreedy informs LiveDebugVariables about new VRegs that is introduced at spill by InlineSpiller. Consider this example LDV: !"var" [48r;128r):0 Loc0=%2 48B %2 = ... ... 128B %7 = ADD %2, ... If %2 is spilled the InlineSpiller will insert spill/reload instructions and introduces some new vregs. So we get 48B %4 = ... 56B spill %4 ... 120B reload %5 128B %3 = ADD %5, ... In the past we did not inform LDV about this, and when reintroducing DBG_VALUE instruction LDV still got information that "var" had the location of the spilled register %2 for the interval [48r;128r). The result was bad, since we mapped "var" to the spill slot even before the spill happened: %4 = ... DBG_VALUE %spill.0, !"var" spill %4 to %spill.0 ... reload %5 %3 = ADD %5, ... This patch will inform LDV about the interval split introduced due to spilling. So the location map in LDV will become !"var" [48r;56r):1 [56r;120r):0 [120r;128r):2 Loc0=%2 Loc1=%4 Loc2=%5 And when inserting DBG_VALUE instructions we get %4 = ... DBG_VALUE %4, !"var" spill %4 to %spill.0 DBG_VALUE %spill.0, !"var" ... reload %5 DBG_VALUE %5, !"var" %3 = ADD %5, ... Fixes: https://bugs.llvm.org/show_bug.cgi?id=38899 Reviewers: jmorse, vsk, aprantl Reviewed By: jmorse Subscribers: dstenb, wuzish, MatzeB, qcolombet, nemanjai, hiraditya, jsji, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D69584 --- diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp index 253bdbb..cace044 100644 --- a/llvm/lib/CodeGen/LiveDebugVariables.cpp +++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp @@ -255,6 +255,25 @@ public: return locations.size() - 1; } + /// Remove (recycle) a location number. If \p LocNo still is used by the + /// locInts nothing is done. + void removeLocationIfUnused(unsigned LocNo) { + // Bail out if LocNo still is used. + for (LocMap::const_iterator I = locInts.begin(); I.valid(); ++I) { + DbgValueLocation Loc = I.value(); + if (Loc.locNo() == LocNo) + return; + } + // Remove the entry in the locations vector, and adjust all references to + // location numbers above the removed entry. + locations.erase(locations.begin() + LocNo); + for (LocMap::iterator I = locInts.begin(); I.valid(); ++I) { + DbgValueLocation Loc = I.value(); + if (!Loc.isUndef() && Loc.locNo() > LocNo) + I.setValueUnchecked(Loc.changeLocNo(Loc.locNo() - 1)); + } + } + /// Ensure that all virtual register locations are mapped. void mapVirtRegs(LDVImpl *LDV); @@ -1073,23 +1092,14 @@ UserValue::splitLocation(unsigned OldLocNo, ArrayRef NewRegs, } } - // Finally, remove any remaining OldLocNo intervals and OldLocNo itself. - locations.erase(locations.begin() + OldLocNo); - LocMapI.goToBegin(); - while (LocMapI.valid()) { - DbgValueLocation v = LocMapI.value(); - if (v.locNo() == OldLocNo) { - LLVM_DEBUG(dbgs() << "Erasing [" << LocMapI.start() << ';' - << LocMapI.stop() << ")\n"); - LocMapI.erase(); - } else { - // Undef values always have location number UndefLocNo, so don't change - // locNo in that case. See getLocationNo(). - if (!v.isUndef() && v.locNo() > OldLocNo) - LocMapI.setValueUnchecked(v.changeLocNo(v.locNo() - 1)); - ++LocMapI; - } - } + // Finally, remove OldLocNo unless it is still used by some interval in the + // locInts map. One case when OldLocNo still is in use is when the register + // has been spilled. In such situations the spilled register is kept as a + // location until rewriteLocations is called (VirtRegMap is mapping the old + // register to the spill slot). So for a while we can have locations that map + // to virtual registers that have been removed from both the MachineFunction + // and from LiveIntervals. + removeLocationIfUnused(OldLocNo); LLVM_DEBUG({ dbgs() << "Split result: \t"; diff --git a/llvm/lib/CodeGen/RegAllocGreedy.cpp b/llvm/lib/CodeGen/RegAllocGreedy.cpp index d27db67..fc12a49 100644 --- a/llvm/lib/CodeGen/RegAllocGreedy.cpp +++ b/llvm/lib/CodeGen/RegAllocGreedy.cpp @@ -3126,6 +3126,11 @@ unsigned RAGreedy::selectOrSplitImpl(LiveInterval &VirtReg, spiller().spill(LRE); setStage(NewVRegs.begin(), NewVRegs.end(), RS_Done); + // Tell LiveDebugVariables about the new ranges. Ranges not being covered by + // the new regs are kept in LDV (still mapping to the old register), until + // we rewrite spilled locations in LDV at a later stage. + DebugVars->splitRegister(VirtReg.reg, LRE.regs(), *LIS); + if (VerifyEnabled) MF->verify(this, "After spilling"); } diff --git a/llvm/test/CodeGen/PowerPC/pr38899-split-register-at-spill.mir b/llvm/test/CodeGen/PowerPC/pr38899-split-register-at-spill.mir new file mode 100644 index 0000000..06b8eed --- /dev/null +++ b/llvm/test/CodeGen/PowerPC/pr38899-split-register-at-spill.mir @@ -0,0 +1,74 @@ +# RUN: llc -mtriple=powerpc64le-unknown-unknown -start-before=greedy -stop-after=virtregrewriter -o - %s | FileCheck %s + +--- | + ; Function Attrs: nounwind + define signext i32 @test1(i32 signext %a, i32 signext %b) local_unnamed_addr !dbg !8 { + entry: + %mul = mul nsw i32 %b, %a, !dbg !18 + call void @llvm.dbg.value(metadata i32 %mul, metadata !15, metadata !DIExpression()), !dbg !19 + tail call void asm sideeffect "", "~{r0},~{r1},~{r2},~{r3},~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r10},~{r11},~{r12},~{r13},~{r14},~{r15},~{r16},~{r17},~{r18},~{r19},~{r20},~{r21},~{r22},~{r23},~{r24},~{r25},~{r26},~{r27},~{r28},~{r29},~{r30},~{r31}"() #2, !dbg !20, !srcloc !25 + ret i32 %mul, !dbg !26 + } + + ; Function Attrs: nounwind readnone speculatable willreturn + declare void @llvm.dbg.value(metadata, metadata, metadata) + + !llvm.dbg.cu = !{!0} + !llvm.module.flags = !{!3, !4, !5, !6} + !llvm.ident = !{!7} + + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 8.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None) + !1 = !DIFile(filename: "foo.c", directory: "/") + !2 = !{} + !3 = !{i32 2, !"Dwarf Version", i32 4} + !4 = !{i32 2, !"Debug Info Version", i32 3} + !5 = !{i32 1, !"wchar_size", i32 4} + !6 = !{i32 7, !"PIC Level", i32 2} + !7 = !{!"clang version 8.0.0"} + !8 = distinct !DISubprogram(name: "test1", scope: !1, file: !1, line: 8, type: !9, scopeLine: 8, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !12) + !9 = !DISubroutineType(types: !10) + !10 = !{!11, !11, !11} + !11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !12 = !{!15} + !15 = !DILocalVariable(name: "c", scope: !8, file: !1, line: 9, type: !11) + !16 = !DILocation(line: 8, column: 14, scope: !8) + !17 = !DILocation(line: 8, column: 21, scope: !8) + !18 = !DILocation(line: 9, column: 13, scope: !8) + !19 = !DILocation(line: 9, column: 7, scope: !8) + !20 = !DILocation(line: 2, column: 3, scope: !21, inlinedAt: !24) + !21 = distinct !DISubprogram(name: "force_spill", scope: !1, file: !1, line: 1, type: !22, scopeLine: 1, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !2) + !22 = !DISubroutineType(types: !23) + !23 = !{null} + !24 = distinct !DILocation(line: 10, column: 3, scope: !8) + !25 = !{i32 55} + !26 = !DILocation(line: 11, column: 3, scope: !8) + +... +--- +name: test1 +tracksRegLiveness: true +body: | + bb.0.entry: + liveins: $x3, $x4 + + %4:gprc = nsw MULLW $r4, $r3, debug-location !18 + DBG_VALUE %4, $noreg, !15, !DIExpression(), debug-location !19 + INLINEASM &"", 1, 12, implicit-def dead early-clobber $r0, 12, implicit-def early-clobber $r1, 12, implicit-def early-clobber $r2, 12, implicit-def dead early-clobber $r3, 12, implicit-def dead early-clobber $r4, 12, implicit-def dead early-clobber $r5, 12, implicit-def dead early-clobber $r6, 12, implicit-def dead early-clobber $r7, 12, implicit-def dead early-clobber $r8, 12, implicit-def dead early-clobber $r9, 12, implicit-def dead early-clobber $r10, 12, implicit-def dead early-clobber $r11, 12, implicit-def dead early-clobber $r12, 12, implicit-def early-clobber $r13, 12, implicit-def dead early-clobber $r14, 12, implicit-def dead early-clobber $r15, 12, implicit-def dead early-clobber $r16, 12, implicit-def dead early-clobber $r17, 12, implicit-def dead early-clobber $r18, 12, implicit-def dead early-clobber $r19, 12, implicit-def dead early-clobber $r20, 12, implicit-def dead early-clobber $r21, 12, implicit-def dead early-clobber $r22, 12, implicit-def dead early-clobber $r23, 12, implicit-def dead early-clobber $r24, 12, implicit-def dead early-clobber $r25, 12, implicit-def dead early-clobber $r26, 12, implicit-def dead early-clobber $r27, 12, implicit-def dead early-clobber $r28, 12, implicit-def dead early-clobber $r29, 12, implicit-def dead early-clobber $r30, 12, implicit-def early-clobber $r31, !25, debug-location !20 + %5:g8rc = EXTSW_32_64 %4, debug-location !26 + $x3 = COPY %5, debug-location !26 + BLR8 implicit $lr8, implicit $rm, implicit $x3, debug-location !26 + +... + +# Verify that we get three DBG_VALUE instructions. One between the MULLW and +# the spill, one between the spill and reload, and one after the reload. +# +# CHECK-LABEL: name: test1 +# CHECK: renamable [[REG1:\$r[0-9]+]] = nsw MULLW +# CHECK-NEXT: DBG_VALUE [[REG1]], $noreg, [[VAR:![0-9]+]], !DIExpression(), +# CHECK-NEXT: STW killed renamable [[REG1]], 0, %stack.0 :: +# CHECK-NEXT: DBG_VALUE %stack.0, 0, [[VAR]], !DIExpression(), +# CHECK-NEXT: INLINEASM +# CHECK-NEXT: renamable [[REG2:\$r[0-9]+]] = LWZ 0, %stack.0, +# CHECK-NEXT: DBG_VALUE [[REG2]], $noreg, [[VAR]], !DIExpression(), +# CHECK-NEXT: EXTSW_32_64 killed renamable [[REG2]],