[RISCV] Generate correct ELF EFlags when .ll file has target-abi attribute

[StephenFan]

Summary

In the past, when construct RISCVAsmBackend, MCTargetOptions.ABIName would be passed and stored in RISCVAsmBackend.
But MCTargetOptions.ABIName can only be specified by -target-abi xxx in command line, if the .ll file has target-abi attribute, the codegen module will ignore it. And the generated object file would have incorrect EFlags value.

https://github.com/llvm/llvm-project/issues/50591 also caused by this problem.

This patch override the AsmPrinter::emitFunctionEntryLabel function and use it to set the target abi value that get from .ll file's target-abi attribute. And storing the target-abi in RISCVTargetStreamer instead of RISCVAsmBackend.

[StephenFan]

remove the content in patch D121073

[StephenFan]

fix

[khchen]

llvm/test/CodeGen/RISCV/module-target-abi2.ll

16

The elf attribute becomes correct, but I think the assembly is still incorrect?
LLVM can not read the -target-abi from IR and overwrite the MCTargetOptions.ABIName,
It's why https://reviews.llvm.org/D102582 would like to report an error if users give the mismatch -target-abi comparing to IR's.

[StephenFan]

llvm/test/CodeGen/RISCV/module-target-abi2.ll

16

Do you mind giving a test case that can reflect the assembly is incorrect ?
This patch wants to generate the correct eflags if the target-abi information is in IR instead of being specified by command line.
Indeed, LLVM can not read the -target-abi IR from and overwrite the MCTargetOptions.ABIName, So I put the ABI info in RISCVTargetStreamer, and set it before the end of AsmPrinter. Because I think at the end of AsmPrinter, the ABI value should have been determined. And mips seems to be too.

[khchen]

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

262

Why do we need to have the additional checking here? I think we already have check in line 246~256?

Could we have a test to show this check could catch an error?

llvm/lib/Target/RISCV/MCTargetDesc/RISCVBaseInfo.cpp

37 ↗

(On Diff #413708)

redundant line?

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp

39

Original program flow does an assert checking after init the variable ABI. Does make sense to keep the checking?
If yes, maybe we could move the checking into setTargetABI function, then we don't need to check it after getTargetABI in line 155.

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp

89

Why do we need to have additional check here?
Could we have a test to show this check could catch an error?

llvm/test/CodeGen/RISCV/module-target-abi2.ll

16

Sorry, I'm wrong.
In the getSubtargetImpl the backend already reads the ABI from IR and ignore the checking if MCTargetOptions.ABIName is empty.

Cool, it's a good solution better then I did before in https://reviews.llvm.org/D72246, Thanks!!!

I think for enabling LTO, for now, we only need to find a way to encode the module scope march in bitcode file (I had PoC in https://reviews.llvm.org/D106347)

[StephenFan]

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

262

Not only the computeTargetABI function computes the target abi, but also check if the abi string and feature bits is valid (by calling parseFeatureBits). Before this patch, the computeTargetABI function was called in the RISCVAsmBackend 's constructor. And the RISCVAsmBackend was used by almost all the tools(llvm-mc, llc ...) no matter output asm or object file, so the checking of abi string and feature bits are must be did. However, In this patch, I moved the calling of computeTargetABI function into RISCVTargetELFStreamer. If we use llvm-mc and the output file is not object file, the RISCVTargetELFStreamer is not needed and will not be constructed. Then the checking of abi string and feature bits will not be did. And some existing test cases that check abi string and feature bits will fail. So I added these extra checking here.

And I also think these extra checking is weird. Do you have a better solution ?

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp

89

The reason is the same as what I said above.

[StephenFan]

Address @khchen 's comments.

ChangeLog:

1. Remove redundent line in RISCVBaseInfo.cpp
2. Move ABI assert checking into setTarget function.

[khchen]

LGTM. thanks!

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp

89

I think we could remove this checking and update expected ERROR message in mattr-invalid-combination.ll and mattr-invalid-combination.s from standard user-level extension 'e' requires 'rv32' to RV32E can't be enabled for an RV64 target in another NFC patch.

[asb]

This needs a rebase, but otherwise LGTM. Thanks for addressing this!

[StephenFan]

rebase and fix warning

[StephenFan]

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp

89

Hi @khchen, D122290 addresses your suggestion about this.

llvm/lib/Target/RISCV/AsmParser/RISCVAsmParser.cpp

if (ABIName.endswith("f") &&
                 "target-abi)\n";
     } else if (ABIName.endswith("d") &&
                !getSTI().getFeatureBits()[RISCV::FeatureStdExtD]) {
       errs() << "Hard-float 'd' ABI can't be used for a target that "
                 "doesn't support the D instruction set extension (ignoring "
                 "target-abi)\n";
     }
 
+    // Use computeTargetABI to check if ABIName is valid. If invalid, output
+    // error message.
+    RISCVABI::computeTargetABI(STI.getTargetTriple(), STI.getFeatureBits(),
+                               ABIName);
+
     const MCObjectFileInfo *MOFI = Parser.getContext().getObjectFileInfo();
     ParserOptions.IsPicEnabled = MOFI->isPositionIndependent();
   }
 };
 
 /// RISCVOperand - Instances of this class represent a parsed machine
 /// instruction
 struct RISCVOperand : public MCParsedAsmOperand {

llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.h

 class raw_ostream;
 
 class RISCVAsmBackend : public MCAsmBackend {
   const MCSubtargetInfo &STI;
   uint8_t OSABI;
   bool Is64Bit;
   bool ForceRelocs = false;
   const MCTargetOptions &TargetOptions;
-  RISCVABI::ABI TargetABI = RISCVABI::ABI_Unknown;
 
 public:
   RISCVAsmBackend(const MCSubtargetInfo &STI, uint8_t OSABI, bool Is64Bit,
                   const MCTargetOptions &Options)
       : MCAsmBackend(support::little), STI(STI), OSABI(OSABI), Is64Bit(Is64Bit),
         TargetOptions(Options) {
-    TargetABI = RISCVABI::computeTargetABI(
-        STI.getTargetTriple(), STI.getFeatureBits(), Options.getABIName());
     RISCVFeatures::validate(STI.getTargetTriple(), STI.getFeatureBits());
   }
   ~RISCVAsmBackend() override = default;
 
   void setForceRelocs() { ForceRelocs = true; }
 
   // Return Size with extra Nop Bytes for alignment directive in code section.
   bool shouldInsertExtraNopBytesForCodeAlign(const MCAlignFragment &AF,
bool relaxDwarfLineAddr(MCDwarfLineAddrFragment &DF, MCAsmLayout &Layout,
                           bool &WasRelaxed) const override;
   bool relaxDwarfCFA(MCDwarfCallFrameFragment &DF, MCAsmLayout &Layout,
                      bool &WasRelaxed) const override;
 
   bool writeNopData(raw_ostream &OS, uint64_t Count,
                     const MCSubtargetInfo *STI) const override;
 
   const MCTargetOptions &getTargetOptions() const { return TargetOptions; }
-  RISCVABI::ABI getTargetABI() const { return TargetABI; }
 };
 }
 
 #endif

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.h

struct AttributeItem {
     unsigned IntValue;
     std::string StringValue;
   };
 
   StringRef CurrentVendor;
   SmallVector<AttributeItem, 64> Contents;
 
   MCSection *AttributeSection = nullptr;
+  const MCSubtargetInfo &STI;
 
   AttributeItem *getAttributeItem(unsigned Attribute) {
     for (size_t i = 0; i < Contents.size(); ++i)
       if (Contents[i].Tag == Attribute)
         return &Contents[i];
     return nullptr;
   }
 
public:
   void emitDirectiveOptionPush() override;
   void emitDirectiveOptionPop() override;
   void emitDirectiveOptionPIC() override;
   void emitDirectiveOptionNoPIC() override;
   void emitDirectiveOptionRVC() override;
   void emitDirectiveOptionNoRVC() override;
   void emitDirectiveOptionRelax() override;
   void emitDirectiveOptionNoRelax() override;
+
+  void finish() override;
 };
 
 MCELFStreamer *createRISCVELFStreamer(MCContext &C,
                                       std::unique_ptr<MCAsmBackend> MAB,
                                       std::unique_ptr<MCObjectWriter> MOW,
                                       std::unique_ptr<MCCodeEmitter> MCE,
                                       bool RelaxAll);
 }
 #endif

llvm/lib/Target/RISCV/MCTargetDesc/RISCVELFStreamer.cpp

 #include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCCodeEmitter.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSectionELF.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCValue.h"
-#include "llvm/Support/Casting.h"
 #include "llvm/Support/LEB128.h"
 #include "llvm/Support/RISCVAttributes.h"
 
 using namespace llvm;
 
 // This part is for ELF object output.
 RISCVTargetELFStreamer::RISCVTargetELFStreamer(MCStreamer &S,
                                                const MCSubtargetInfo &STI)
-    : RISCVTargetStreamer(S), CurrentVendor("riscv") {
+    : RISCVTargetStreamer(S), CurrentVendor("riscv"), STI(STI) {
   MCAssembler &MCA = getStreamer().getAssembler();
   const FeatureBitset &Features = STI.getFeatureBits();
   auto &MAB = static_cast<RISCVAsmBackend &>(MCA.getBackend());
-  RISCVABI::ABI ABI = MAB.getTargetABI();
-  assert(ABI != RISCVABI::ABI_Unknown && "Improperly initialised target ABI");
-
-  unsigned EFlags = MCA.getELFHeaderEFlags();
-
-  if (Features[RISCV::FeatureStdExtC])
-    EFlags |= ELF::EF_RISCV_RVC;
-
-  switch (ABI) {
-  case RISCVABI::ABI_ILP32:
-  case RISCVABI::ABI_LP64:
-    break;
-  case RISCVABI::ABI_ILP32F:
-  case RISCVABI::ABI_LP64F:
-    EFlags |= ELF::EF_RISCV_FLOAT_ABI_SINGLE;
-    break;
-  case RISCVABI::ABI_ILP32D:
-  case RISCVABI::ABI_LP64D:
-    EFlags |= ELF::EF_RISCV_FLOAT_ABI_DOUBLE;
-    break;
-  case RISCVABI::ABI_ILP32E:
-    EFlags |= ELF::EF_RISCV_RVE;
-    break;
-  case RISCVABI::ABI_Unknown:
-    llvm_unreachable("Improperly initialised target ABI");
-  }
-
-  MCA.setELFHeaderEFlags(EFlags);
+  setTargetABI(RISCVABI::computeTargetABI(STI.getTargetTriple(), Features,
+                                          MAB.getTargetOptions().getABIName()));
 }
 
 MCELFStreamer &RISCVTargetELFStreamer::getStreamer() {
   return static_cast<MCELFStreamer &>(Streamer);
 }
 
 void RISCVTargetELFStreamer::emitDirectiveOptionPush() {}
 void RISCVTargetELFStreamer::emitDirectiveOptionPop() {}
case AttributeType::NumericAndText:
       Result += getULEB128Size(item.IntValue);
       Result += item.StringValue.size() + 1; // string + '\0';
       break;
     }
   }
   return Result;
 }
 
+void RISCVTargetELFStreamer::finish() {
+  RISCVTargetStreamer::finish();
+  MCAssembler &MCA = getStreamer().getAssembler();
+  const FeatureBitset &Features = STI.getFeatureBits();
+  RISCVABI::ABI ABI = getTargetABI();
+
+  unsigned EFlags = MCA.getELFHeaderEFlags();
+
+  if (Features[RISCV::FeatureStdExtC])
+    EFlags |= ELF::EF_RISCV_RVC;
+
+  switch (ABI) {
+  case RISCVABI::ABI_ILP32:
+  case RISCVABI::ABI_LP64:
+    break;
+  case RISCVABI::ABI_ILP32F:
+  case RISCVABI::ABI_LP64F:
+    EFlags |= ELF::EF_RISCV_FLOAT_ABI_SINGLE;
+    break;
+  case RISCVABI::ABI_ILP32D:
+  case RISCVABI::ABI_LP64D:
+    EFlags |= ELF::EF_RISCV_FLOAT_ABI_DOUBLE;
+    break;
+  case RISCVABI::ABI_ILP32E:
+    EFlags |= ELF::EF_RISCV_RVE;
+    break;
+  case RISCVABI::ABI_Unknown:
+    llvm_unreachable("Improperly initialised target ABI");
+  }
+
+  MCA.setELFHeaderEFlags(EFlags);
+}
+
 namespace {
 class RISCVELFStreamer : public MCELFStreamer {
   static std::pair<unsigned, unsigned> getRelocPairForSize(unsigned Size) {
     switch (Size) {
     default:
       llvm_unreachable("unsupported fixup size");
     case 1:
       return std::make_pair(RISCV::fixup_riscv_add_8, RISCV::fixup_riscv_sub_8);

llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp

 
 static MCSubtargetInfo *createRISCVMCSubtargetInfo(const Triple &TT,
                                                    StringRef CPU, StringRef FS) {
   if (CPU.empty())
     CPU = TT.isArch64Bit() ? "generic-rv64" : "generic-rv32";
   if (CPU == "generic")
     report_fatal_error(Twine("CPU 'generic' is not supported. Use ") +
                        (TT.isArch64Bit() ? "generic-rv64" : "generic-rv32"));
-  return createRISCVMCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FS);
+
+  MCSubtargetInfo *STI =
+      createRISCVMCSubtargetInfoImpl(TT, CPU, /*TuneCPU*/ CPU, FS);
+
+  // Check if Feature string is valid
+  auto ISAInfo =
+      RISCVFeatures::parseFeatureBits(TT.isArch64Bit(), STI->getFeatureBits());
+  if (!ISAInfo)
+    report_fatal_error(ISAInfo.takeError());
+  else
+    return STI;
 }
 
 static MCInstPrinter *createRISCVMCInstPrinter(const Triple &T,
                                                unsigned SyntaxVariant,
                                                const MCAsmInfo &MAI,
                                                const MCInstrInfo &MII,
                                                const MCRegisterInfo &MRI) {
   return new RISCVInstPrinter(MAI, MII, MRI);

llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.h

 //===-- RISCVTargetStreamer.h - RISCV Target Streamer ----------*- C++ -*--===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVTARGETSTREAMER_H
 #define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVTARGETSTREAMER_H
 
+#include "RISCV.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 
 namespace llvm {
 
 class formatted_raw_ostream;
 
 class RISCVTargetStreamer : public MCTargetStreamer {
+  RISCVABI::ABI TargetABI = RISCVABI::ABI_Unknown;
+
 public:
   RISCVTargetStreamer(MCStreamer &S);
   void finish() override;
 
   virtual void emitDirectiveOptionPush();
   virtual void emitDirectiveOptionPop();
   virtual void emitDirectiveOptionPIC();
   virtual void emitDirectiveOptionNoPIC();
   virtual void emitDirectiveOptionRVC();
   virtual void emitDirectiveOptionNoRVC();
   virtual void emitDirectiveOptionRelax();
   virtual void emitDirectiveOptionNoRelax();
   virtual void emitAttribute(unsigned Attribute, unsigned Value);
   virtual void finishAttributeSection();
   virtual void emitTextAttribute(unsigned Attribute, StringRef String);
   virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                                     StringRef StringValue);
 
   void emitTargetAttributes(const MCSubtargetInfo &STI);
+  void setTargetABI(RISCVABI::ABI ABI);
+  RISCVABI::ABI getTargetABI() const { return TargetABI; }
 };
 
 // This part is for ascii assembly output
 class RISCVTargetAsmStreamer : public RISCVTargetStreamer {
   formatted_raw_ostream &OS;
 
   void finishAttributeSection() override;
   void emitAttribute(unsigned Attribute, unsigned Value) override;

llvm/lib/Target/RISCV/MCTargetDesc/RISCVTargetStreamer.cpp

 void RISCVTargetStreamer::emitDirectiveOptionNoRelax() {}
 void RISCVTargetStreamer::emitAttribute(unsigned Attribute, unsigned Value) {}
 void RISCVTargetStreamer::finishAttributeSection() {}
 void RISCVTargetStreamer::emitTextAttribute(unsigned Attribute,
                                             StringRef String) {}
 void RISCVTargetStreamer::emitIntTextAttribute(unsigned Attribute,
                                                unsigned IntValue,
                                                StringRef StringValue) {}
+void RISCVTargetStreamer::setTargetABI(RISCVABI::ABI ABI) {
+  assert(ABI != RISCVABI::ABI_Unknown && "Improperly initialized target ABI");
+  TargetABI = ABI;
+}
 
 void RISCVTargetStreamer::emitTargetAttributes(const MCSubtargetInfo &STI) {
   if (STI.hasFeature(RISCV::FeatureRV32E))
     emitAttribute(RISCVAttrs::STACK_ALIGN, RISCVAttrs::ALIGN_4);
   else
     emitAttribute(RISCVAttrs::STACK_ALIGN, RISCVAttrs::ALIGN_16);
 
   auto ParseResult = RISCVFeatures::parseFeatureBits(

llvm/lib/Target/RISCV/RISCVAsmPrinter.cpp

 
 #define DEBUG_TYPE "asm-printer"
 
 STATISTIC(RISCVNumInstrsCompressed,
           "Number of RISC-V Compressed instructions emitted");
 
 namespace {
 class RISCVAsmPrinter : public AsmPrinter {
-  const MCSubtargetInfo *STI;
+  const MCSubtargetInfo *MCSTI;
+  const RISCVSubtarget *STI;
+  RISCVABI::ABI ABI = RISCVABI::ABI_Unknown;
 
 public:
   explicit RISCVAsmPrinter(TargetMachine &TM,
                            std::unique_ptr<MCStreamer> Streamer)
-      : AsmPrinter(TM, std::move(Streamer)), STI(TM.getMCSubtargetInfo()) {}
+      : AsmPrinter(TM, std::move(Streamer)), MCSTI(TM.getMCSubtargetInfo()) {}
 
   StringRef getPassName() const override { return "RISCV Assembly Printer"; }
 
   bool runOnMachineFunction(MachineFunction &MF) override;
 
   void emitInstruction(const MachineInstr *MI) override;
 
   bool PrintAsmOperand(const MachineInstr *MI, unsigned OpNo,
                        const char *ExtraCode, raw_ostream &OS) override;
   bool PrintAsmMemoryOperand(const MachineInstr *MI, unsigned OpNo,
                              const char *ExtraCode, raw_ostream &OS) override;
 
   void EmitToStreamer(MCStreamer &S, const MCInst &Inst);
   bool emitPseudoExpansionLowering(MCStreamer &OutStreamer,
                                    const MachineInstr *MI);
 
   // Wrapper needed for tblgenned pseudo lowering.
   bool lowerOperand(const MachineOperand &MO, MCOperand &MCOp) const {
     return LowerRISCVMachineOperandToMCOperand(MO, MCOp, *this);
   }
 
   void emitStartOfAsmFile(Module &M) override;
   void emitEndOfAsmFile(Module &M) override;
 
+  void emitFunctionEntryLabel() override;
+
 private:
   void emitAttributes();
 };
 }
 
 #define GEN_COMPRESS_INSTR
 #include "RISCVGenCompressInstEmitter.inc"
 void RISCVAsmPrinter::EmitToStreamer(MCStreamer &S, const MCInst &Inst) {

 }
 
 bool RISCVAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
   // Set the current MCSubtargetInfo to a copy which has the correct
   // feature bits for the current MachineFunction
   MCSubtargetInfo &NewSTI =
     OutStreamer->getContext().getSubtargetCopy(*TM.getMCSubtargetInfo());
   NewSTI.setFeatureBits(MF.getSubtarget().getFeatureBits());
-  STI = &NewSTI;
+  MCSTI = &NewSTI;
+  STI = &MF.getSubtarget<RISCVSubtarget>();
 
   SetupMachineFunction(MF);
   emitFunctionBody();
   return false;
 }
 
 void RISCVAsmPrinter::emitStartOfAsmFile(Module &M) {
   if (TM.getTargetTriple().isOSBinFormatELF())
     emitAttributes();
 }
 
 void RISCVAsmPrinter::emitEndOfAsmFile(Module &M) {
   RISCVTargetStreamer &RTS =
       static_cast<RISCVTargetStreamer &>(*OutStreamer->getTargetStreamer());
 
   if (TM.getTargetTriple().isOSBinFormatELF())
     RTS.finishAttributeSection();
 }
 
 void RISCVAsmPrinter::emitAttributes() {
   RISCVTargetStreamer &RTS =
       static_cast<RISCVTargetStreamer &>(*OutStreamer->getTargetStreamer());
-  RTS.emitTargetAttributes(*STI);
+  RTS.emitTargetAttributes(*MCSTI);
+}
+
+void RISCVAsmPrinter::emitFunctionEntryLabel() {
+  AsmPrinter::emitFunctionEntryLabel();
+  RISCVTargetStreamer &RTS =
+      static_cast<RISCVTargetStreamer &>(*OutStreamer->getTargetStreamer());
+  RTS.setTargetABI(STI->getTargetABI());
 }
 
 // Force static initialization.
 extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeRISCVAsmPrinter() {
   RegisterAsmPrinter<RISCVAsmPrinter> X(getTheRISCV32Target());
   RegisterAsmPrinter<RISCVAsmPrinter> Y(getTheRISCV64Target());
 }

llvm/test/CodeGen/RISCV/module-target-abi2.ll

 ; RUN: llc -mtriple=riscv32 < %s 2>&1 \
 ; RUN:   | FileCheck -check-prefix=DEFAULT %s
 ; RUN: not --crash llc -mtriple=riscv32 -target-abi ilp32 < %s 2>&1 \
 ; RUN:   | FileCheck -check-prefix=RV32IF-ILP32 %s
 ; RUN: llc -mtriple=riscv32 -target-abi ilp32f < %s 2>&1 \
 ; RUN:   | FileCheck -check-prefix=RV32IF-ILP32F %s
 ; RUN: llc -mtriple=riscv32 -filetype=obj < %s | llvm-readelf -h - | FileCheck -check-prefixes=FLAGS %s
 
 ; RV32IF-ILP32: -target-abi option != target-abi module flag
 
-; FLAGS: Flags: 0x0
-; // this should be "Flags :0x2, single-float ABI", it will be fixed later.
+; FLAGS: Flags: 0x2, single-float ABI
 
 define float @foo(i32 %a) nounwind #0 {
 ; DEFAULT: # %bb.0:
 ; DEFAULT-NEXT: fcvt.s.w fa0, a0
 ; DEFAULT-NEXT: ret
 ; RV32IF-ILP32F: # %bb.0:
 ; RV32IF-ILP32F: fcvt.s.w fa0, a0
 ; RV32IF-ILP32F: ret
   %conv = sitofp i32 %a to float
   ret float %conv
 }
 
 attributes #0 = { "target-features"="+f"}
 !llvm.module.flags = !{!0}
 !0 = !{i32 1, !"target-abi", !"ilp32f"}