From 7838051bda3ee8b95c73c6d5e1a97ea3570684f1 Mon Sep 17 00:00:00 2001 From: "Duncan P. N. Exon Smith" Date: Wed, 6 May 2015 19:11:20 +0000 Subject: [PATCH] DwarfDebug: Emit number of bytes in .debug_loc entry directly Emit the number of bytes in a `.debug_loc` entry directly. The old code created temp labels (expensive), emitted the difference between them, and then emitted one on each side of the relevant bytes. (I'm looking at `llc` memory usage on `verify-uselistorder.lto.opt.bc` (the optimized version of ld64's `-save-temps` when linking the `verify-uselistorder` executable in an LTO bootstrap). I've hacked `MCContext::Allocate()` to just call `malloc()` instead of using the `BumpPtrAllocator` so that the heap profile is easier to read. As far as peak memory is concerned, `MCContext::Allocate()` is equivalent to a leak, since it only gets freed at process teardown. In my heap profile, this patch drops memory usage of `DwarfDebug::emitDebugLoc()` from 132.56 MB (11.4%) down to 29.86 MB (2.7%) at peak memory. Some of that must be noise from `SmallVector` (or other) allocations -- peak memory only dropped from 1160 MB down to 1100 MB -- but this nevertheless shaves 5% off the top.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236629 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 9 +++------ test/CodeGen/X86/2010-05-25-DotDebugLoc.ll | 3 +-- test/CodeGen/X86/2010-05-26-DotDebugLoc.ll | 10 ++-------- test/DebugInfo/X86/dbg-value-range.ll | 5 +---- 4 files changed, 7 insertions(+), 20 deletions(-) diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 4fe4f26c923..e275d3aac7d 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -1545,16 +1545,13 @@ void DebugLocEntry::finalize(const AsmPrinter &AP, DebugLocStream &Locs, } void DwarfDebug::emitDebugLocEntryLocation(const DebugLocStream::Entry &Entry) { + // Emit the size. Asm->OutStreamer->AddComment("Loc expr size"); - MCSymbol *begin = Asm->OutStreamer->getContext().CreateTempSymbol(); - MCSymbol *end = Asm->OutStreamer->getContext().CreateTempSymbol(); - Asm->EmitLabelDifference(end, begin, 2); - Asm->OutStreamer->EmitLabel(begin); + Asm->EmitInt16(DebugLocs.getBytes(Entry).size()); + // Emit the entry. APByteStreamer Streamer(*Asm); emitDebugLocEntry(Streamer, Entry); - // Close the range. - Asm->OutStreamer->EmitLabel(end); } // Emit locations into the debug loc section. diff --git a/test/CodeGen/X86/2010-05-25-DotDebugLoc.ll b/test/CodeGen/X86/2010-05-25-DotDebugLoc.ll index e14365ac848..3b99e91915f 100644 --- a/test/CodeGen/X86/2010-05-25-DotDebugLoc.ll +++ b/test/CodeGen/X86/2010-05-25-DotDebugLoc.ll @@ -2,8 +2,7 @@ ; RUN: llc -mtriple=x86_64-pc-linux -O2 -regalloc=basic < %s | FileCheck %s ; Test to check .debug_loc support. This test case emits many debug_loc entries. -; CHECK: .short {{.*}} # Loc expr size -; CHECK-NEXT: .Ltmp +; CHECK: .short 1 # Loc expr size ; CHECK-NEXT: DW_OP_reg %0 = type { double } diff --git a/test/CodeGen/X86/2010-05-26-DotDebugLoc.ll b/test/CodeGen/X86/2010-05-26-DotDebugLoc.ll index 788853e4308..3670c556aa7 100644 --- a/test/CodeGen/X86/2010-05-26-DotDebugLoc.ll +++ b/test/CodeGen/X86/2010-05-26-DotDebugLoc.ll @@ -77,18 +77,12 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon ; CHECK-NEXT: .quad [[SET1]] ; CHECK-NEXT: [[SET2:.*]] = [[LABEL]]-Lfunc_begin0 ; CHECK-NEXT: .quad [[SET2]] -; CHECK-NEXT: Lset{{.*}} = Ltmp{{.*}}-Ltmp{{.*}} ## Loc expr size -; CHECK-NEXT: .short Lset{{.*}} -; CHECK-NEXT: Ltmp{{.*}}: +; CHECK-NEXT: .short 1 ## Loc expr size ; CHECK-NEXT: .byte 85 -; CHECK-NEXT: Ltmp{{.*}}: ; CHECK-NEXT: [[SET3:.*]] = [[LABEL]]-Lfunc_begin0 ; CHECK-NEXT: .quad [[SET3]] ; CHECK-NEXT: [[SET4:.*]] = [[CLOBBER]]-Lfunc_begin0 ; CHECK-NEXT: .quad [[SET4]] -; CHECK-NEXT: Lset{{.*}} = Ltmp{{.*}}-Ltmp{{.*}} ## Loc expr size -; CHECK-NEXT: .short Lset{{.*}} -; CHECK-NEXT: Ltmp{{.*}}: +; CHECK-NEXT: .short 1 ## Loc expr size ; CHECK-NEXT: .byte 83 -; CHECK-NEXT: Ltmp{{.*}}: !38 = !{i32 1, !"Debug Info Version", i32 3} diff --git a/test/DebugInfo/X86/dbg-value-range.ll b/test/DebugInfo/X86/dbg-value-range.ll index fcde006320d..a8fa9073fa7 100644 --- a/test/DebugInfo/X86/dbg-value-range.ll +++ b/test/DebugInfo/X86/dbg-value-range.ll @@ -55,11 +55,8 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) nounwind readnon ;CHECK-NEXT: .quad ;CHECK-NEXT: [[CLOBBER_OFF:Lset.*]] = [[CLOBBER]]-{{.*}} ;CHECK-NEXT: .quad [[CLOBBER_OFF]] -;CHECK-NEXT: Lset{{.*}} = Ltmp{{.*}}-Ltmp{{.*}} -;CHECK-NEXT: .short Lset -;CHECK-NEXT: Ltmp +;CHECK-NEXT: .short 1 ## Loc expr size ;CHECK-NEXT: .byte 85 ## DW_OP_reg -;CHECK-NEXT: Ltmp ;CHECK-NEXT: .quad 0 ;CHECK-NEXT: .quad 0 !24 = !{i32 1, !"Debug Info Version", i32 3} -- 2.34.1