Specify that lzma needs to be installed (doesn't really, but to keep things...

Specify that lzma needs to be installed (doesn't really, but to keep things simple), and try to support running pyston not from src/

README.md

@@ -14,7 +14,7 @@ Benchmarks are not currently that meaningful since the supported set of benchmar
 
 ##### Contributing
 
-Pyston welcomes any sorts of contributions; please see [CONTRIBUTING.md](https://github.com/dropbox/pyston/blob/master/CONTRIBUTING.md) for details.
+Pyston welcomes any kind of contribution; please see [CONTRIBUTING.md](https://github.com/dropbox/pyston/blob/master/CONTRIBUTING.md) for details.
 
 ### Roadmap
 

docs/INSTALLING.md

@@ -100,6 +100,7 @@ To install:
 
 ```
 cd ~/pyston_deps
+sudo apt-get install liblzma-dev
 wget http://valgrind.org/downloads/valgrind-3.9.0.tar.bz2
 tar xvf valgrind-3.9.0.tar.bz2
 mkdir valgrind-3.9.0-install

src/codegen/parser.cpp

@@ -19,6 +19,9 @@
 #include <cstring>
 #include <sys/stat.h>
 
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+
 #include "core/options.h"
 #include "core/stats.h"
 #include "core/types.h"
@@ -750,7 +753,15 @@ AST_Module* parse(const char* fn) {
 #define LENGTH_SUFFIX_LENGTH 4
 
 static void _reparse(const char* fn, const std::string &cache_fn) {
-    std::string cmdline = std::string("python -S codegen/parse_ast.py ") + fn;
+    llvm::SmallString<128> parse_ast_fn;
+    // TODO supposed to pass argv0, main_addr to this function:
+    parse_ast_fn = llvm::sys::fs::getMainExecutable(NULL, NULL);
+    assert(parse_ast_fn.size() && "could not find the path to the pyston src dir");
+    llvm::sys::path::remove_filename(parse_ast_fn);
+    llvm::sys::path::append(parse_ast_fn, "codegen/parse_ast.py");
+
+    std::string cmdline = std::string("python -S ") + parse_ast_fn.str().str() + " " + fn;
+    printf("%s\n", cmdline.c_str());
     FILE *parser = popen(cmdline.c_str(), "r");
     FILE *cache_fp = fopen(cache_fn.c_str(), "w");
     assert(cache_fp);