From 5032e5a61381437174e035de2a7dd728978f7bd5 Mon Sep 17 00:00:00 2001 From: Anton Korobeynikov Date: Wed, 17 Jan 2007 10:33:08 +0000 Subject: [PATCH] * Fix one more bug in PIC codegen: extra load is needed for *all* non-statics. * Introduce new option to output zero-initialized data to .bss section. This can reduce size of binaries. Enable it by default for ELF & Cygwin/Mingw targets. Probably, Darwin should be also added. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33299 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Target/TargetAsmInfo.h | 7 +++++++ include/llvm/Target/TargetOptions.h | 2 ++ lib/Target/TargetAsmInfo.cpp | 1 + lib/Target/TargetMachine.cpp | 6 ++++++ lib/Target/X86/X86ATTAsmPrinter.cpp | 23 ++++++++++------------- lib/Target/X86/X86AsmPrinter.cpp | 11 +++++++++-- lib/Target/X86/X86Subtarget.cpp | 6 +++++- test/CodeGen/X86/test-pic-6.ll | 17 +++++++++++++++++ 8 files changed, 57 insertions(+), 16 deletions(-) create mode 100644 test/CodeGen/X86/test-pic-6.ll diff --git a/include/llvm/Target/TargetAsmInfo.h b/include/llvm/Target/TargetAsmInfo.h index 6d80a7ebc86..1b957898f9f 100644 --- a/include/llvm/Target/TargetAsmInfo.h +++ b/include/llvm/Target/TargetAsmInfo.h @@ -38,6 +38,10 @@ namespace llvm { /// DataSection - Section directive for standard data. /// const char *DataSection; // Defaults to ".data". + + /// BSSSection - Section directive for uninitialized data. + /// + const char *BSSSection; // Default to ".bss". /// AddressSize - Size of addresses used in file. /// @@ -313,6 +317,9 @@ namespace llvm { const char *getDataSection() const { return DataSection; } + const char *getBSSSection() const { + return BSSSection; + } unsigned getAddressSize() const { return AddressSize; } diff --git a/include/llvm/Target/TargetOptions.h b/include/llvm/Target/TargetOptions.h index 4d21b0b0603..89234de6445 100644 --- a/include/llvm/Target/TargetOptions.h +++ b/include/llvm/Target/TargetOptions.h @@ -54,6 +54,8 @@ namespace llvm { /// generate libcalls to the software floating point library instead of /// target FP instructions. extern bool UseSoftFloat; + + extern bool NoZerosInBSS; } // End llvm namespace #endif diff --git a/lib/Target/TargetAsmInfo.cpp b/lib/Target/TargetAsmInfo.cpp index b1845007440..b90eaa16689 100644 --- a/lib/Target/TargetAsmInfo.cpp +++ b/lib/Target/TargetAsmInfo.cpp @@ -19,6 +19,7 @@ using namespace llvm; TargetAsmInfo::TargetAsmInfo() : TextSection(".text"), DataSection(".data"), + BSSSection(".bss"), AddressSize(4), NeedsSet(false), MaxInstLength(4), diff --git a/lib/Target/TargetMachine.cpp b/lib/Target/TargetMachine.cpp index 7547614a717..f6b3fd09f0b 100644 --- a/lib/Target/TargetMachine.cpp +++ b/lib/Target/TargetMachine.cpp @@ -28,6 +28,7 @@ namespace llvm { bool UnsafeFPMath; bool FiniteOnlyFPMathOption; bool UseSoftFloat; + bool NoZerosInBSS; Reloc::Model RelocationModel; CodeModel::Model CMModel; } @@ -61,6 +62,11 @@ namespace { cl::desc("Generate software floating point library calls"), cl::location(UseSoftFloat), cl::init(false)); + cl::opt + DontPlaceZerosInBSS("nozero-initialized-in-bss", + cl::desc("Don't place zero-initialized symbols into bss section"), + cl::location(NoZerosInBSS), + cl::init(false)); cl::opt DefRelocationModel( diff --git a/lib/Target/X86/X86ATTAsmPrinter.cpp b/lib/Target/X86/X86ATTAsmPrinter.cpp index 02faf7cdb39..1dd53c7a02a 100755 --- a/lib/Target/X86/X86ATTAsmPrinter.cpp +++ b/lib/Target/X86/X86ATTAsmPrinter.cpp @@ -323,22 +323,19 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo, O << Offset; if (isMemOp) { - if (isExt) { - if (Subtarget->isPICStyleGOT()) { + if (Subtarget->isPICStyleGOT()) { + if (Subtarget->GVRequiresExtraLoad(GV, TM, false)) O << "@GOT"; - } else if (Subtarget->isPICStyleRIPRel()) { + else + O << "@GOTOFF"; + } else + if (isExt && Subtarget->isPICStyleRIPRel()) O << "@GOTPCREL(%rip)"; - } else if (Subtarget->is64Bit() && !NotRIPRel) - // Use rip when possible to reduce code size, except when - // index or base register are also part of the address. e.g. - // foo(%rip)(%rcx,%rax,4) is not legal - O << "(%rip)"; - } else { - if (Subtarget->is64Bit() && !NotRIPRel) + else if (Subtarget->is64Bit() && !NotRIPRel) + // Use rip when possible to reduce code size, except when + // index or base register are also part of the address. e.g. + // foo(%rip)(%rcx,%rax,4) is not legal O << "(%rip)"; - else if (Subtarget->isPICStyleGOT()) - O << "@GOTOFF"; - } } return; diff --git a/lib/Target/X86/X86AsmPrinter.cpp b/lib/Target/X86/X86AsmPrinter.cpp index 767ab23ce3b..bea3914fe64 100644 --- a/lib/Target/X86/X86AsmPrinter.cpp +++ b/lib/Target/X86/X86AsmPrinter.cpp @@ -28,6 +28,7 @@ #include "llvm/Assembly/Writer.h" #include "llvm/Support/Mangler.h" #include "llvm/Target/TargetAsmInfo.h" +#include "llvm/Target/TargetOptions.h" using namespace llvm; static X86FunctionInfo calculateFunctionInfo(const Function *F, @@ -149,7 +150,10 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) { O << "\t.zerofill __DATA__, __common, " << name << ", " << Size << ", " << Align; } else { - SwitchToDataSection(TAI->getDataSection(), I); + if (!NoZerosInBSS && TAI->getBSSSection()) + SwitchToDataSection(TAI->getBSSSection(), I); + else + SwitchToDataSection(TAI->getDataSection(), I); if (TAI->getLCOMMDirective() != NULL) { if (I->hasInternalLinkage()) { O << TAI->getLCOMMDirective() << name << "," << Size; @@ -224,7 +228,10 @@ bool X86SharedAsmPrinter::doFinalization(Module &M) { SwitchToDataSection(SectionName.c_str()); } else { - SwitchToDataSection(TAI->getDataSection(), I); + if (C->isNullValue() && !NoZerosInBSS && TAI->getBSSSection()) + SwitchToDataSection(TAI->getBSSSection(), I); + else + SwitchToDataSection(TAI->getDataSection(), I); } break; diff --git a/lib/Target/X86/X86Subtarget.cpp b/lib/Target/X86/X86Subtarget.cpp index 5f2342ff4d3..be5c64d6d3b 100644 --- a/lib/Target/X86/X86Subtarget.cpp +++ b/lib/Target/X86/X86Subtarget.cpp @@ -36,10 +36,14 @@ bool X86Subtarget::GVRequiresExtraLoad(const GlobalValue* GV, bool isDirectCall) const { if (TM.getRelocationModel() != Reloc::Static) - if (isTargetDarwin() || isPICStyleGOT()) { + if (isTargetDarwin()) { return (!isDirectCall && (GV->hasWeakLinkage() || GV->hasLinkOnceLinkage() || (GV->isExternal() && !GV->hasNotBeenReadFromBytecode()))); + } else if (isPICStyleGOT()) { + // Extra load is needed for all non-statics. + return (!isDirectCall && + (GV->isExternal() || !GV->hasInternalLinkage())); } else if (isTargetCygMing() || isTargetWindows()) { return (GV->hasDLLImportLinkage()); } diff --git a/test/CodeGen/X86/test-pic-6.ll b/test/CodeGen/X86/test-pic-6.ll new file mode 100644 index 00000000000..9f295319d1c --- /dev/null +++ b/test/CodeGen/X86/test-pic-6.ll @@ -0,0 +1,17 @@ +; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux-gnu -relocation-model=pic && +; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux-gnu -relocation-model=pic | grep _GLOBAL_OFFSET_TABLE_ && +; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux-gnu -relocation-model=pic | grep piclabel | wc -l | grep 3 && +; RUN: llvm-as < %s | llc -mtriple=i686-pc-linux-gnu -relocation-model=pic | grep GOT | wc -l | grep 3 + +%ptr = global i32* null +%dst = global i32 0 +%src = global i32 0 + +define void %foo() { +entry: + store i32* %dst, i32** %ptr + %tmp.s = load i32* %src + store i32 %tmp.s, i32* %dst + ret void +} + -- 2.34.1