From 7125c9519fcdbb39eb580398ccfbc1741ddd895c Mon Sep 17 00:00:00 2001 From: Keno Fischer Date: Tue, 12 Jan 2016 13:38:15 +0000 Subject: [PATCH] [ARM] Fix several state persistence bugs Summary: This fixes three bugs, in all of which state is not or incorrecly reset between objects (i.e. when reusing the same pass manager to create multiple object files): 1) AttributeSection needs to be reset to nullptr, because otherwise the backend will try to emit into the old object file's attribute section causing a segmentation fault. 2) MappingSymbolCounter needs to be reset, otherwise the second object file will start where the first one left off. 3) The MCStreamer base class resets the Streamer's e_flags settings. Since EF_ARM_EABI_VER5 is set on streamer creation, we need to set it again after the MCStreamer was rest. Also rename Reset (uppser case) to EHReset to avoid confusion with reset (lower case). Reviewers: rengolin Differential Revision: http://reviews.llvm.org/D15950 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@257473 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/MC/MCStreamer.h | 4 +++ .../ARM/MCTargetDesc/ARMELFStreamer.cpp | 28 ++++++++++++++++--- .../ARM/MCTargetDesc/ARMTargetStreamer.cpp | 3 ++ test/MC/ARM/twice.ll | 9 ++++++ 4 files changed, 40 insertions(+), 4 deletions(-) create mode 100644 test/MC/ARM/twice.ll diff --git a/include/llvm/MC/MCStreamer.h b/include/llvm/MC/MCStreamer.h index 494f02dfad3..04d143ffef6 100644 --- a/include/llvm/MC/MCStreamer.h +++ b/include/llvm/MC/MCStreamer.h @@ -131,6 +131,10 @@ public: void finish() override; + /// Reset any state between object emissions, i.e. the equivalent of + /// MCStreamer's reset method. + virtual void reset(); + /// Callback used to implement the ldr= pseudo. /// Add a new entry to the constant pool for the current section and return an /// MCExpr that can be used to refer to the constant pool location. diff --git a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp index 6084f22c847..57577dc834b 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp @@ -388,6 +388,9 @@ private: size_t calculateContentSize() const; + // Reset state between object emissions + void reset() override; + public: ARMTargetELFStreamer(MCStreamer &S) : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::FK_INVALID), @@ -415,7 +418,7 @@ public: MCCodeEmitter *Emitter, bool IsThumb) : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb), MappingSymbolCounter(0), LastEMS(EMS_None) { - Reset(); + EHReset(); } ~ARMELFStreamer() {} @@ -579,7 +582,10 @@ private: } // Helper functions for ARM exception handling directives - void Reset(); + void EHReset(); + + // Reset state between object emissions + void reset() override; void EmitPersonalityFixup(StringRef Name); void FlushPendingOffset(); @@ -1040,6 +1046,8 @@ void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) { getStreamer().emitInst(Inst, Suffix); } +void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; } + void ARMELFStreamer::FinishImpl() { MCTargetStreamer &TS = *getTargetStreamer(); ARMTargetStreamer &ATS = static_cast(TS); @@ -1048,6 +1056,18 @@ void ARMELFStreamer::FinishImpl() { MCELFStreamer::FinishImpl(); } +void ARMELFStreamer::reset() { + MCTargetStreamer &TS = *getTargetStreamer(); + ARMTargetStreamer &ATS = static_cast(TS); + ATS.reset(); + MappingSymbolCounter = 0; + MCELFStreamer::reset(); + // MCELFStreamer clear's the assembler's e_flags. However, for + // arm we manually set the ABI version on streamer creation, so + // do the same here + getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5); +} + inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags, @@ -1094,7 +1114,7 @@ void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) { Kind)); } -void ARMELFStreamer::Reset() { +void ARMELFStreamer::EHReset() { ExTab = nullptr; FnStart = nullptr; Personality = nullptr; @@ -1164,7 +1184,7 @@ void ARMELFStreamer::emitFnEnd() { SwitchSection(&FnStart->getSection()); // Clean exception handling frame information - Reset(); + EHReset(); } void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; } diff --git a/lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp b/lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp index dad50f2834e..c0d10c89635 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMTargetStreamer.cpp @@ -38,6 +38,9 @@ void ARMTargetStreamer::emitCurrentConstantPool() { // finish() - write out any non-empty assembler constant pools. void ARMTargetStreamer::finish() { ConstantPools->emitAll(Streamer); } +// reset() - Reset any state +void ARMTargetStreamer::reset() {} + // The remaining callbacks should be handled separately by each // streamer. void ARMTargetStreamer::emitFnStart() {} diff --git a/test/MC/ARM/twice.ll b/test/MC/ARM/twice.ll new file mode 100644 index 00000000000..8811632dd56 --- /dev/null +++ b/test/MC/ARM/twice.ll @@ -0,0 +1,9 @@ +; Check for state persistence bugs in the ARM MC backend +; This should neither fail (in the comparison that the second object +; is bit-identical to the first) nor crash. Either failure would most +; likely indicate some state that is not properly reset in the +; appropriate ::reset method. +; RUN: llc -compile-twice -filetype=obj %s -o - + +target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64" +target triple = "armv4t-unknown-linux-gnueabi" -- 2.34.1