[pypy-svn] r14289 - pypy/dist/pypy/translator/llvm2

[hpk at codespeak.net]

Author: hpk
Date: Tue Jul  5 15:42:25 2005
New Revision: 14289

Added:
   pypy/dist/pypy/translator/llvm2/varsize.py   (contents, props changed)
Log:
(hpk/rxe) missing file from previous checkin r14288

Added: pypy/dist/pypy/translator/llvm2/varsize.py
==============================================================================
--- (empty file)
+++ pypy/dist/pypy/translator/llvm2/varsize.py	Tue Jul  5 15:42:25 2005
@@ -0,0 +1,40 @@
+
+# example for an array constructor in concrete llvm code: 
+# (thanks to chris lattner) 
+""" this function generates a LLVM function like the following:
+%array = type { int, [0 x double] }
+%array *%NewArray(int %len) {
+   ;; Get the offset of the 'len' element of the array from the null
+   ;; pointer.
+   %size = getelementptr %array* null, int 0, uint 1, %int %len
+   %usize = cast double* %size to uint
+   %ptr = malloc sbyte, uint %usize
+   %result = cast sbyte* %ptr to %array*
+   %arraylength = getelementptr %array* %result, int 0, uint 0
+   store int %len, int* %arraylength 
+   ret %array* %result
+}"""
+
+def write_constructor(codewriter, ref, constructor_decl, elemtype, 
+                      indices_to_array=(), atomicmalloc=False): 
+    #varsized arrays and structs look like this: 
+    #Array: {int length , elemtype*}
+    #Struct: {...., Array}
+
+    # the following indices access the last element in the array 
+    elemindices = list(indices_to_array) + [("uint", 1), ("int", "%len")]
+    
+    codewriter.openfunc(constructor_decl)
+    codewriter.getelementptr("%size", ref + "*", "null", *elemindices) 
+    codewriter.cast("%usize", elemtype + "*", "%size", "uint")
+    codewriter.malloc("%ptr", "sbyte", "%usize", atomic=atomicmalloc)
+    codewriter.cast("%result", "sbyte*", "%ptr", ref + "*")
+    
+    # the following accesses the length field of the array 
+    codewriter.getelementptr("%arraylength", ref + "*", 
+                             "%result", 
+                             indices_to_array + ("uint", 0))
+    codewriter.store("int", "%len", "%arraylength")
+    codewriter.ret(ref + "*", "%result")
+    codewriter.closefunc()
+