hanchenye-llvm-project/llvm/tools/gccld/util.cpp

288 lines
7.0 KiB
C++

//===- util.cpp - Utility functions ---------------------------------------===//
//
// This file contains utility functions for gccld. It essentially holds
// anything from the original gccld.cpp source that was either incidental
// or not inlined.
//
//===----------------------------------------------------------------------===//
#include "llvm/Module.h"
#include "Config/string.h"
#include <fstream>
#include <string>
#include <set>
//
// Function: PrintAndReturn ()
//
// Description:
// Prints a message (usually error message) to standard error (stderr) and
// returns a value usable for an exit status.
//
// Inputs:
// progname - The name of the program (i.e. argv[0]).
// Message - The message to print to standard error.
// Extra - Extra information to print between the program name and thei
// message. It is optional.
//
// Outputs:
// None.
//
// Return value:
// Returns a value that can be used as the exit status (i.e. for exit()).
//
int
PrintAndReturn (const char *progname,
const std::string &Message,
const std::string &Extra = "")
{
std::cerr << progname << Extra << ": " << Message << "\n";
return 1;
}
//
// Function: IsArchive ()
//
// Description:
// Determine if the specified file is an ar archive. It determines this by
// checking the magic string at the beginning of the file.
//
// Inputs:
// filename - A C++ string containing the name of the file.
//
// Outputs:
// None.
//
// Return value:
// TRUE - The file is an archive.
// FALSE - The file is not an archive.
//
bool
IsArchive (const std::string &filename)
{
std::string ArchiveMagic("!<arch>\012");
char buf[1 + ArchiveMagic.size()];
std::ifstream f(filename.c_str());
f.read(buf, ArchiveMagic.size());
buf[ArchiveMagic.size()] = '\0';
return ArchiveMagic == buf;
}
//
// Function: GetAllDefinedSymbols ()
//
// Description:
// Find all of the defined symbols in the specified module.
//
// Inputs:
// M - The module in which to find defined symbols.
//
// Outputs:
// DefinedSymbols - A set of C++ strings that will contain the name of all
// defined symbols.
//
// Return value:
// None.
//
void
GetAllDefinedSymbols (Module *M, std::set<std::string> &DefinedSymbols)
{
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
if (I->hasName() && !I->isExternal() && !I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
//
// Function: GetAllUndefinedSymbols ()
//
// Description:
// This calculates the set of undefined symbols that still exist in an LLVM
// module. This is a bit tricky because there may be two symbols with the
// same name but different LLVM types that will be resolved to each other but
// aren't currently (thus we need to treat it as resolved).
//
// Inputs:
// M - The module in which to find undefined symbols.
//
// Outputs:
// UndefinedSymbols - A set of C++ strings containing the name of all
// undefined symbols.
//
// Return value:
// None.
//
void
GetAllUndefinedSymbols(Module *M, std::set<std::string> &UndefinedSymbols)
{
std::set<std::string> DefinedSymbols;
UndefinedSymbols.clear(); // Start out empty
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
if (I->hasName()) {
if (I->isExternal())
UndefinedSymbols.insert(I->getName());
else if (!I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
for (Module::giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
if (I->hasName()) {
if (I->isExternal())
UndefinedSymbols.insert(I->getName());
else if (!I->hasInternalLinkage())
DefinedSymbols.insert(I->getName());
}
// Prune out any defined symbols from the undefined symbols set...
for (std::set<std::string>::iterator I = UndefinedSymbols.begin();
I != UndefinedSymbols.end(); )
if (DefinedSymbols.count(*I))
UndefinedSymbols.erase(I++); // This symbol really is defined!
else
++I; // Keep this symbol in the undefined symbols list
}
//
//
// Function: copy_env()
//
// Description:
// This function takes an array of environment variables and makes a
// copy of it. This copy can then be manipulated any way the caller likes
// without affecting the process's real environment.
//
// Inputs:
// envp - An array of C strings containing an environment.
//
// Outputs:
// None.
//
// Return value:
// NULL - An error occurred.
//
// Otherwise, a pointer to a new array of C strings is returned. Every string
// in the array is a duplicate of the one in the original array (i.e. we do
// not copy the char *'s from one array to another).
//
char **
copy_env (char ** const envp)
{
// The new environment list
char ** newenv;
// The number of entries in the old environment list
int entries;
//
// Count the number of entries in the old list;
//
for (entries = 0; envp[entries] != NULL; entries++)
{
;
}
//
// Add one more entry for the NULL pointer that ends the list.
//
++entries;
//
// If there are no entries at all, just return NULL.
//
if (entries == 0)
{
return NULL;
}
//
// Allocate a new environment list.
//
if ((newenv = new (char *) [entries]) == NULL)
{
return NULL;
}
//
// Make a copy of the list. Don't forget the NULL that ends the list.
//
entries = 0;
while (envp[entries] != NULL)
{
newenv[entries] = new char[strlen (envp[entries]) + 1];
strcpy (newenv[entries], envp[entries]);
++entries;
}
newenv[entries] = NULL;
return newenv;
}
//
// Function: remove_env()
//
// Description:
// Remove the specified environment variable from the environment array.
//
// Inputs:
// name - The name of the variable to remove. It cannot be NULL.
// envp - The array of environment variables. It cannot be NULL.
//
// Outputs:
// envp - The pointer to the specified variable name is removed.
//
// Return value:
// None.
//
// Notes:
// This is mainly done because functions to remove items from the environment
// are not available across all platforms. In particular, Solaris does not
// seem to have an unsetenv() function or a setenv() function (or they are
// undocumented if they do exist).
//
void
remove_env (const char * name, char ** const envp)
{
// Pointer for scanning arrays
register char * p;
// Index for selecting elements of the environment array
register int index;
for (index=0; envp[index] != NULL; index++)
{
//
// Find the first equals sign in the array and make it an EOS character.
//
p = strchr (envp[index], '=');
if (p == NULL)
{
continue;
}
else
{
*p = '\0';
}
//
// Compare the two strings. If they are equal, zap this string.
// Otherwise, restore it.
//
if (!strcmp (name, envp[index]))
{
*envp[index] = '\0';
}
else
{
*p = '=';
}
}
return;
}