From e3ae958f94f6ceaaad9fed107316fbcc022a8628 Mon Sep 17 00:00:00 2001 From: "Duncan P. N. Exon Smith" Date: Sun, 24 May 2015 16:14:59 +0000 Subject: [PATCH] AsmPrinter: Emit the DwarfStringPool offset directly when possible Change `DwarfStringPool` to calculate byte offsets on-the-fly, and update `DwarfUnit::getLocalString()` to use a `DIEInteger` instead of a `DIEDelta` when Dwarf doesn't use relocations (i.e., Mach-O). This eliminates another call to `EmitLabelDifference()`, and drops memory usage from 865 MB down to 861 MB, around 0.5%. (I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc`; see r236629 for details.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238114 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DwarfStringPool.cpp | 32 ++++++++++--------- lib/CodeGen/AsmPrinter/DwarfStringPool.h | 19 ++++++++--- lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 7 ++-- .../DebugInfo/2010-06-29-InlinedFnLocalVar.ll | 2 +- test/DebugInfo/X86/stringpool.ll | 7 ++-- 5 files changed, 39 insertions(+), 28 deletions(-) diff --git a/lib/CodeGen/AsmPrinter/DwarfStringPool.cpp b/lib/CodeGen/AsmPrinter/DwarfStringPool.cpp index fc98ed4b784..a599126f0b7 100644 --- a/lib/CodeGen/AsmPrinter/DwarfStringPool.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfStringPool.cpp @@ -12,12 +12,16 @@ using namespace llvm; -std::pair &DwarfStringPool::getEntry(AsmPrinter &Asm, - StringRef Str) { - std::pair &Entry = Pool[Str]; - if (!Entry.first) { - Entry.second = Pool.size() - 1; - Entry.first = Asm.createTempSymbol(Prefix); +DwarfStringPool::EntryTy &DwarfStringPool::getEntry(AsmPrinter &Asm, + StringRef Str) { + auto &Entry = Pool[Str]; + if (!Entry.Symbol) { + Entry.Index = Pool.size() - 1; + Entry.Offset = NumBytes; + Entry.Symbol = Asm.createTempSymbol(Prefix); + + NumBytes += Str.size() + 1; + assert(NumBytes > Entry.Offset && "Unexpected overflow"); } return Entry; } @@ -32,17 +36,18 @@ void DwarfStringPool::emit(AsmPrinter &Asm, MCSection *StrSection, // Get all of the string pool entries and put them in an array by their ID so // we can sort them. - SmallVector> *, 64> - Entries(Pool.size()); + SmallVector *, 64> Entries(Pool.size()); for (const auto &E : Pool) - Entries[E.getValue().second] = &E; + Entries[E.getValue().Index] = &E; for (const auto &Entry : Entries) { // Emit a label for reference from debug information entries. - Asm.OutStreamer->EmitLabel(Entry->getValue().first); + Asm.OutStreamer->EmitLabel(Entry->getValue().Symbol); // Emit the string itself with a terminating null byte. + Asm.OutStreamer->AddComment("string offset=" + + Twine(Entry->getValue().Offset)); Asm.OutStreamer->EmitBytes( StringRef(Entry->getKeyData(), Entry->getKeyLength() + 1)); } @@ -50,11 +55,8 @@ void DwarfStringPool::emit(AsmPrinter &Asm, MCSection *StrSection, // If we've got an offset section go ahead and emit that now as well. if (OffsetSection) { Asm.OutStreamer->SwitchSection(OffsetSection); - unsigned offset = 0; unsigned size = 4; // FIXME: DWARF64 is 8. - for (const auto &Entry : Entries) { - Asm.OutStreamer->EmitIntValue(offset, size); - offset += Entry->getKeyLength() + 1; - } + for (const auto &Entry : Entries) + Asm.OutStreamer->EmitIntValue(Entry->getValue().Offset, size); } } diff --git a/lib/CodeGen/AsmPrinter/DwarfStringPool.h b/lib/CodeGen/AsmPrinter/DwarfStringPool.h index ba0d595c140..77b6ffaa9f1 100644 --- a/lib/CodeGen/AsmPrinter/DwarfStringPool.h +++ b/lib/CodeGen/AsmPrinter/DwarfStringPool.h @@ -25,8 +25,14 @@ class StringRef; // A String->Symbol mapping of strings used by indirect // references. class DwarfStringPool { - StringMap, BumpPtrAllocator &> Pool; + struct EntryTy { + MCSymbol *Symbol; + unsigned Offset; + unsigned Index; + }; + StringMap Pool; StringRef Prefix; + unsigned NumBytes = 0; public: DwarfStringPool(BumpPtrAllocator &A, AsmPrinter &Asm, StringRef Prefix) @@ -38,19 +44,24 @@ public: /// \brief Returns an entry into the string pool with the given /// string text. MCSymbol *getSymbol(AsmPrinter &Asm, StringRef Str) { - return getEntry(Asm, Str).first; + return getEntry(Asm, Str).Symbol; + } + + /// Get a byte offset into the string pool with the given text. + unsigned getOffset(AsmPrinter &Asm, StringRef Str) { + return getEntry(Asm, Str).Offset; } /// \brief Returns the index into the string pool with the given /// string text. unsigned getIndex(AsmPrinter &Asm, StringRef Str) { - return getEntry(Asm, Str).second; + return getEntry(Asm, Str).Index; } bool empty() const { return Pool.empty(); } private: - std::pair &getEntry(AsmPrinter &Asm, StringRef Str); + EntryTy &getEntry(AsmPrinter &Asm, StringRef Str); }; } #endif diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp index 47a8c6d8264..018d2b9918d 100644 --- a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp @@ -239,14 +239,13 @@ void DwarfUnit::addIndexedString(DIE &Die, dwarf::Attribute Attribute, void DwarfUnit::addLocalString(DIE &Die, dwarf::Attribute Attribute, StringRef String) { - const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); - MCSymbol *Symb = DU->getStringPool().getSymbol(*Asm, String); DIEValue *Value; if (Asm->MAI->doesDwarfUseRelocationsAcrossSections()) - Value = new (DIEValueAllocator) DIELabel(Symb); + Value = new (DIEValueAllocator) + DIELabel(DU->getStringPool().getSymbol(*Asm, String)); else Value = new (DIEValueAllocator) - DIEDelta(Symb, TLOF.getDwarfStrSection()->getBeginSymbol()); + DIEInteger(DU->getStringPool().getOffset(*Asm, String)); DIEValue *Str = new (DIEValueAllocator) DIEString(Value, String); Die.addValue(Attribute, dwarf::DW_FORM_strp, Str); } diff --git a/test/DebugInfo/2010-06-29-InlinedFnLocalVar.ll b/test/DebugInfo/2010-06-29-InlinedFnLocalVar.ll index 609ad885565..27a0535bc8c 100644 --- a/test/DebugInfo/2010-06-29-InlinedFnLocalVar.ll +++ b/test/DebugInfo/2010-06-29-InlinedFnLocalVar.ll @@ -3,7 +3,7 @@ ; CHECK: section_info ; CHECK: DW_TAG_structure_type -; CHECK-NEXT: info_string +; CHECK-NEXT: DW_AT_name @i = common global i32 0 ; [#uses=2] diff --git a/test/DebugInfo/X86/stringpool.ll b/test/DebugInfo/X86/stringpool.ll index 23c0fc46fb1..62b2b1bb55c 100644 --- a/test/DebugInfo/X86/stringpool.ll +++ b/test/DebugInfo/X86/stringpool.ll @@ -18,7 +18,7 @@ ; LINUX: .section .debug_str,"MS",@progbits,1 ; LINUX: yyyy ; DARWIN: .section __DWARF,__debug_str,regular,debug -; DARWIN: yyyy +; DARWIN: .asciz "yyyy" ## string offset=[[YYYY:[0-9]+]] ; Verify that we refer to 'yyyy' with a relocation. ; LINUX: .long .Linfo_string3 # DW_AT_name @@ -30,9 +30,8 @@ ; LINUX-NEXT: .byte 3 ; LINUX-NEXT: .quad yyyy -; Verify that we refer to 'yyyy' without a relocation. -; DARWIN: Lset[[ID:[0-9]+]] = Linfo_string3-Linfo_string ## DW_AT_name -; DARWIN-NEXT: .long Lset[[ID]] +; Verify that we refer to 'yyyy' with a direct offset. +; DARWIN: .long [[YYYY]] ; DARWIN-NEXT: .long {{[0-9]+}} ## DW_AT_type ; DARWIN-NEXT: ## DW_AT_external ; DARWIN-NEXT: .byte 1 ## DW_AT_decl_file