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Avoid using alloca in Windows/Program.inc 

One use needs to copy the alloca into a std::string, and the other use
is before calling CreateProcess, which is very heavyweight anyway.

llvm-svn: 187845
This commit is contained in:
Reid Kleckner 2013-08-07 01:21:33 +00:00
parent 8552e22b07
commit ac20e61b79
1 changed files with 15 additions and 13 deletions
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28
llvm/lib/Support/Windows/Program.inc
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@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "Windows.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/Support/FileSystem.h"
#include <cstdio>
#include <fcntl.h>
@ -46,10 +47,11 @@ std::string sys::FindProgramByName(const std::string &progName) {
// At this point, the file name is valid and does not contain slashes.
// Let Windows search for it.
char buffer[MAX_PATH];
std::string buffer;
buffer.resize(MAX_PATH);
char *dummy = NULL;
DWORD len = SearchPath(NULL, progName.c_str(), ".exe", MAX_PATH,
buffer, &dummy);
&buffer[0], &dummy);
// See if it wasn't found.
if (len == 0)
@ -57,19 +59,19 @@ std::string sys::FindProgramByName(const std::string &progName) {
// See if we got the entire path.
if (len < MAX_PATH)
return std::string(buffer);
return buffer;
// Buffer was too small; grow and retry.
while (true) {
char *b = reinterpret_cast<char *>(_alloca(len+1));
DWORD len2 = SearchPath(NULL, progName.c_str(), ".exe", len+1, b, &dummy);
buffer.resize(len+1);
DWORD len2 = SearchPath(NULL, progName.c_str(), ".exe", len+1, &buffer[0], &dummy);
// It is unlikely the search failed, but it's always possible some file
// was added or removed since the last search, so be paranoid...
if (len2 == 0)
return "";
else if (len2 <= len)
return std::string(b);
return buffer;
len = len2;
}
@ -193,8 +195,8 @@ static bool Execute(void **Data,
}
// Now build the command line.
char *command = reinterpret_cast<char *>(_alloca(len+1));
char *p = command;
OwningArrayPtr<char> command(new char[len+1]);
char *p = command.get();
for (unsigned i = 0; args[i]; i++) {
const char *arg = args[i];
@ -225,7 +227,7 @@ static bool Execute(void **Data,
*p = 0;
// The pointer to the environment block for the new process.
char *envblock = 0;
OwningArrayPtr<char> envblock;
if (envp) {
// An environment block consists of a null-terminated block of
@ -238,8 +240,8 @@ static bool Execute(void **Data,
len += strlen(envp[i]) + 1;
// Now build the environment block.
envblock = reinterpret_cast<char *>(_alloca(len+1));
p = envblock;
envblock.reset(new char[len+1]);
p = envblock.get();
for (unsigned i = 0; envp[i]; i++) {
const char *ev = envp[i];
@ -297,8 +299,8 @@ static bool Execute(void **Data,
fflush(stdout);
fflush(stderr);
std::string ProgramStr = Program;
BOOL rc = CreateProcess(ProgramStr.c_str(), command, NULL, NULL, TRUE, 0,
envblock, NULL, &si, &pi);
BOOL rc = CreateProcess(ProgramStr.c_str(), command.get(), NULL, NULL, TRUE,
0, envblock.get(), NULL, &si, &pi);
DWORD err = GetLastError();
// Regardless of whether the process got created or not, we are done with