#include <stdio.h>
int main( )
{ 
  printf("Hello World!\n");
}

Tintin.local# llvm-gcc helloworld.cpp -S -emit-llvm

Tintin.local# lli helloworld.s
Hello, World

@.str = private constant [13 x i8] c"Hello World!\00", align 1 ;

define i32 @main() ssp {
entry:
  %retval = alloca i32
  %0 = alloca i32
  %"alloca point" = bitcast i32 0 to i32
  %1 = call i32 @puts(i8* getelementptr inbounds ([13 x i8]* @.str, i64 0, i64 0))
  store i32 0, i32* %0, align 4
  %2 = load i32* %0, align 4
  store i32 %2, i32* %retval, align 4
  br label %return
return:
  %retval1 = load i32* %retval
  ret i32 %retval1
}

declare i32 @puts(i8*)

declare  i32 @puts(i8*) 
@global_str = constant [13 x i8] c"Hello World!\00"
define i32 @main { 
  call i32 @puts( [13 x i8] @global_str )
  ret i32 0 
}

lli: test.s:5:29: error: global variable reference must have pointer type
  call i32 @puts( [13 x i8] @global_str )
                            ^

declare i32 @puts (i8*)
@global_str = constant [13 x i8] c"Hello World!\00"

define i32 @main() {
  %temp = getelementptr [13 x i8]*  @global_str, i64 0, i64 0
  call i32 @puts(i8* %temp)
  ret i32 0
}

tintin# llvm-config --cxxflags --ldflags --libs \
-I/usr/include  -DNDEBUG -D_GNU_SOURCE \
-D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS \
-D__STDC_LIMIT_MACROS -O3  -fno-exceptions -fno-rtti -fno-common \
-Woverloaded-virtual -Wcast-qual \
-L/usr/lib  -lpthread -lm \
-lLLVMXCoreCodeGen -lLLVMTableGen -lLLVMSystemZCodeGen \
-lLLVMSparcCodeGen -lLLVMPTXCodeGen \
-lLLVMPowerPCCodeGen -lLLVMMSP430CodeGen -lLLVMMipsCodeGen \
-lLLVMMCJIT -lLLVMRuntimeDyld \
-lLLVMObject -lLLVMMCDisassembler -lLLVMXCoreDesc -lLLVMXCoreInfo \
-lLLVMSystemZDesc -lLLVMSystemZInfo \
-lLLVMSparcDesc -lLLVMSparcInfo -lLLVMPowerPCDesc -lLLVMPowerPCInfo \
-lLLVMPowerPCAsmPrinter \
-lLLVMPTXDesc -lLLVMPTXInfo -lLLVMPTXAsmPrinter -lLLVMMipsDesc \
-lLLVMMipsInfo -lLLVMMipsAsmPrinter \
-lLLVMMSP430Desc -lLLVMMSP430Info -lLLVMMSP430AsmPrinter \
-lLLVMMBlazeDisassembler -lLLVMMBlazeAsmParser \
-lLLVMMBlazeCodeGen -lLLVMMBlazeDesc -lLLVMMBlazeAsmPrinter \
-lLLVMMBlazeInfo -lLLVMLinker -lLLVMipo \
-lLLVMInterpreter -lLLVMInstrumentation -lLLVMJIT -lLLVMExecutionEngine \
-lLLVMDebugInfo -lLLVMCppBackend \
-lLLVMCppBackendInfo -lLLVMCellSPUCodeGen -lLLVMCellSPUDesc \
-lLLVMCellSPUInfo -lLLVMCBackend \
-lLLVMCBackendInfo -lLLVMBlackfinCodeGen -lLLVMBlackfinDesc \
-lLLVMBlackfinInfo -lLLVMBitWriter \
-lLLVMX86Disassembler -lLLVMX86AsmParser -lLLVMX86CodeGen \
-lLLVMX86Desc -lLLVMX86AsmPrinter -lLLVMX86Utils \
-lLLVMX86Info -lLLVMAsmParser -lLLVMARMDisassembler -lLLVMARMAsmParser \
-lLLVMARMCodeGen -lLLVMARMDesc \
-lLLVMARMAsmPrinter -lLLVMARMInfo -lLLVMArchive -lLLVMBitReader \
-lLLVMAlphaCodeGen -lLLVMSelectionDAG \
-lLLVMAsmPrinter -lLLVMMCParser -lLLVMCodeGen -lLLVMScalarOpts \
-lLLVMInstCombine -lLLVMTransformUtils \
-lLLVMipa -lLLVMAnalysis -lLLVMTarget -lLLVMCore -lLLVMAlphaDesc \
-lLLVMAlphaInfo -lLLVMMC -lLLVMSupport

explicit Module(StringRef ModuleID, LLVMContext& C);

llvm::LLVMContext& context = llvm::getGlobalContext();

llvm::Module* module = new llvm::Module("top", context);

llvm::LLVMContext& context = llvm::getGlobalContext();

llvm::Module* module = new llvm::Module("top", context);

llvm::IRBuilder<> builder(context);

#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Support/IRBuilder.h"

int main()
{
  llvm::LLVMContext& context = llvm::getGlobalContext();
  llvm::Module* module = new llvm::Module("top", context);
  llvm::IRBuilder<> builder(context); 

  module->dump( );
}

; ModuleID = 'top'

#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Support/IRBuilder.h"

int main()
{
  llvm::LLVMContext& context = llvm::getGlobalContext();
  llvm::Module *module = new llvm::Module("top", context);
  llvm::IRBuilder<> builder(context); 

  llvm::FunctionType *funcType = 
      llvm::FunctionType::get(builder.getInt32Ty(), false);
  llvm::Function *mainFunc = 
      llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module);

  module->dump( );
}

; ModuleID = 'top'
declare void @main()

#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Support/IRBuilder.h"

int main()
{
  llvm::LLVMContext& context = llvm::getGlobalContext();
  llvm::Module *module = new llvm::Module("top", context);
  llvm::IRBuilder<> builder(context); 

  llvm::FunctionType *funcType = 
      llvm::FunctionType::get(builder.getInt32Ty(), false);
  llvm::Function *mainFunc = 
      llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module);

  llvm::BasicBlock *entry = llvm::BasicBlock::Create(context, "entrypoint", mainFunc);
  builder.SetInsertPoint(entry);

  module->dump( );
}

; ModuleID = 'top'
define void @main() { 
entrypoint: 
}

#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Support/IRBuilder.h"

int main()
{
  llvm::LLVMContext& context = llvm::getGlobalContext();
  llvm::Module *module = new llvm::Module("top", context);
  llvm::IRBuilder<> builder(context); 

  llvm::FunctionType *funcType = 
      llvm::FunctionType::get(builder.getVoidTy(), false);
  llvm::Function *mainFunc = 
      llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module);

  llvm::BasicBlock *entry = llvm::BasicBlock::Create(context, "entrypoint", mainFunc);
  builder.SetInsertPoint(entry);

  llvm::Value *helloWorld = builder.CreateGlobalStringPtr("hello world!\n");

  module->dump( );
}

; ModuleID = 'top'
@0 = internal unnamed_addr constant [14 x i8] c"hello world!\0A\00"
define void @main() {
entrypoint:
}

  std::vector<llvm::Type *> putsArgs;
  putsArgs.push_back(builder.getInt8Ty()->getPointerTo());
  llvm::ArrayRef<llvm::Type*>  argsRef(putsArgs);

  llvm::FunctionType *putsType = 
    llvm::FunctionType::get(builder.getInt32Ty(), argsRef, false);
  llvm::Constant *putsFunc = module->getOrInsertFunction("puts", putsType);

; ModuleID = 'top'
@0 = internal unnamed_addr constant [14 x i8] c"hello world!\0A\00"
define void @main() {
entrypoint:
}
declare i32 @puts(i8*)

#include "llvm/ADT/ArrayRef.h"
#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Function.h"
#include "llvm/BasicBlock.h"
#include "llvm/Support/IRBuilder.h"
#include <vector>
#include <string>

int main()
{
  llvm::LLVMContext & context = llvm::getGlobalContext();
  llvm::Module *module = new llvm::Module("asdf", context);
  llvm::IRBuilder<> builder(context);

  llvm::FunctionType *funcType = llvm::FunctionType::get(builder.getVoidTy(), false);
  llvm::Function *mainFunc = 
    llvm::Function::Create(funcType, llvm::Function::ExternalLinkage, "main", module);
  llvm::BasicBlock *entry = llvm::BasicBlock::Create(context, "entrypoint", mainFunc);
  builder.SetInsertPoint(entry);

  llvm::Value *helloWorld = builder.CreateGlobalStringPtr("hello world!\n");

  std::vector<llvm::Type *> putsArgs;
  putsArgs.push_back(builder.getInt8Ty()->getPointerTo());
  llvm::ArrayRef<llvm::Type*>  argsRef(putsArgs);

  llvm::FunctionType *putsType = 
    llvm::FunctionType::get(builder.getInt32Ty(), argsRef, false);
  llvm::Constant *putsFunc = module->getOrInsertFunction("puts", putsType);

  builder.CreateCall(putsFunc, helloWorld);
  builder.CreateRetVoid();
  module->dump();
}