gllvm/shared/environment.go

//
// OCCAM
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package shared

import (
	"os"
	"strings"
)

const (

	//ELFSectionName is the name of our ELF section of "bitcode paths".
	ELFSectionName = ".llvm_bc"

	//DarwinSegmentName is the name of our MACH-O segment of "bitcode paths".
	DarwinSegmentName = "__WLLVM"

	//DarwinSectionName is the name of our MACH-O section of "bitcode paths".
	DarwinSectionName = "__llvm_bc"
)

//LLVMToolChainBinDir is the user configured directory holding the LLVM binary tools.
var LLVMToolChainBinDir string

//LLVMCCName is the user configured name of the clang compiler.
var LLVMCCName string

//LLVMCXXName is the user configured name of the clang++ compiler.
var LLVMCXXName string

//LLVMARName is the user configured name of the llvm-ar.
var LLVMARName string

//LLVMLINKName is the user configured name of the llvm-link.
var LLVMLINKName string

//LLVMConfigureOnly is the user configured flag indicating a single pass mode is required.
var LLVMConfigureOnly string

//LLVMBitcodeStorePath is the user configured location of the bitcode archive.
var LLVMBitcodeStorePath string

//LLVMLoggingLevel is the user configured logging level: ERROR, WARNING, INFO, DEBUG.
var LLVMLoggingLevel string

//LLVMLoggingFile is the path to the optional logfile (useful when configuring)
var LLVMLoggingFile string

//LLVMObjcopy is the path to the objcopy executable used to attach the bitcode on *nix.
var LLVMObjcopy string

//LLVMLd is the path to the ld executable used to attach the bitcode on OSX.
var LLVMLd string

//LLVMbcGen is the list of args to pass to clang during the bitcode generation step.
var LLVMbcGen []string

//LLVMLtoLDFLAGS is the list of extra flags to pass to the linking steps, when unde -flto
var LLVMLtoLDFLAGS []string

const (
	envpath    = "LLVM_COMPILER_PATH"
	envcc      = "LLVM_CC_NAME"
	envcxx     = "LLVM_CXX_NAME"
	envar      = "LLVM_AR_NAME"
	envlnk     = "LLVM_LINK_NAME"
	envcfg     = "WLLVM_CONFIGURE_ONLY"
	envbc      = "WLLVM_BC_STORE"
	envlvl     = "WLLVM_OUTPUT_LEVEL"
	envfile    = "WLLVM_OUTPUT_FILE"
	envld      = "GLLVM_LD"      //iam: we are deviating from wllvm here.
	envobjcopy = "GLLVM_OBJCOPY" //iam: we are deviating from wllvm here.
	//wllvm uses a BINUTILS_TARGET_PREFIX, which seems less general.
	//iam: 03/24/2020 new feature to pass things like "-flto -fwhole-program-vtables"
	// to clang during the bitcode generation step
	envbcgen = "LLVM_BITCODE_GENERATION_FLAGS"
	//iam: 10/11/2020 extra linking arguments to add to the linking step when we are doing
	// link time optimization.
	envltolink = "LTO_LINKING_FLAGS"
)

func init() {
	FetchEnvironment()
}

// PrintEnvironment is used for printing the aspects of the environment that concern us
func PrintEnvironment() {
	vars := []string{envpath, envcc, envcxx, envar, envlnk, envcfg, envbc, envlvl, envfile, envobjcopy, envld, envbcgen}

	informUser("\nLiving in this environment:\n\n")
	for _, v := range vars {
		val, defined := os.LookupEnv(v)
		if defined {
			informUser("%v = \"%v\"\n", v, val)
		} else {
			informUser("%v is NOT defined\n", v)
		}
	}

}

// ResetEnvironment resets the globals, it is only used in testing
func ResetEnvironment() {
	LLVMToolChainBinDir = ""
	LLVMCCName = ""
	LLVMCXXName = ""
	LLVMARName = ""
	LLVMLINKName = ""
	LLVMConfigureOnly = ""
	LLVMBitcodeStorePath = ""
	LLVMLoggingLevel = ""
	LLVMLoggingFile = ""
	LLVMObjcopy = ""
	LLVMLd = ""
	LLVMbcGen = []string{}
	LLVMLtoLDFLAGS = []string{}
}

// FetchEnvironment is used in initializing our globals, it is also used in testing
func FetchEnvironment() {
	LLVMToolChainBinDir = os.Getenv(envpath)
	LLVMCCName = os.Getenv(envcc)
	LLVMCXXName = os.Getenv(envcxx)
	LLVMARName = os.Getenv(envar)
	LLVMLINKName = os.Getenv(envlnk)

	LLVMConfigureOnly = os.Getenv(envcfg)
	LLVMBitcodeStorePath = os.Getenv(envbc)

	LLVMLoggingLevel = os.Getenv(envlvl)
	LLVMLoggingFile = os.Getenv(envfile)

	LLVMObjcopy = os.Getenv(envobjcopy)
	LLVMLd = os.Getenv(envld)

	LLVMbcGen = strings.Fields(os.Getenv(envbcgen))
	LLVMLtoLDFLAGS = strings.Fields(os.Getenv(envltolink))
}