Do not cast pointers to arrays of differently sized integers. (#485)

Casting between `int64_t *` and `int32_t *` does *not* maintain the
values in the array. Instead, it tells the compiler to interpret the
memory at that pointer as an array of a different type (i.e., two
`int32_t` elements "become" one `int64_t` element). That can lead to all
kinds of errors and is likely not what was intended.

Remove the pointer casts to allow the compiler to emit an error on
compile-time instead of potentially causing, e.g., an array overflow on
runtime if `sunindextype` has a different size from `KLU_INDEXTYPE`.

---------

Signed-off-by: Markus Mützel <markus.muetzel@gmx.de>
Co-authored-by: Cody Balos <balos1@llnl.gov>

CHANGELOG.md

@@ -76,6 +76,9 @@ allocated.
 Fix bug on LLP64 platforms (like Windows 64-bit) where `KLU_INDEXTYPE` could be
 32 bits wide even if `SUNDIALS_INT64_T` is defined.
 
+Check if size of `SuiteSparse_long` is 8 if the size of `sunindextype` is 8
+when using KLU.
+
 ## Changes to SUNDIALS in release v7.0.0
 
 ### Major Feature

cmake/tpl/SundialsKLU.cmake

@@ -57,6 +57,22 @@ message(STATUS "KLU_INCLUDE_DIR: ${KLU_INCLUDE_DIR}")
 if(KLU_FOUND AND (NOT KLU_WORKS))
   # Do any checks which don't require compilation first.
 
+  if(SUNDIALS_INDEX_SIZE MATCHES "64")
+    # Check size of SuiteSparse_long
+    include(CheckTypeSize)
+    set(save_CMAKE_EXTRA_INCLUDE_FILES ${CMAKE_EXTRA_INCLUDE_FILES})
+    list(APPEND CMAKE_EXTRA_INCLUDE_FILES "klu.h")
+    set(save_CMAKE_REQUIRED_INCLUDES ${CMAKE_REQUIRED_INCLUDES})
+    list(APPEND CMAKE_REQUIRED_INCLUDES ${KLU_INCLUDE_DIR})
+    check_type_size("SuiteSparse_long" SIZEOF_SUITESPARSE_LONG)
+    set(CMAKE_EXTRA_INCLUDE_FILES ${save_CMAKE_EXTRA_INCLUDE_FILES})
+    set(CMAKE_REQUIRED_INCLUDES ${save_CMAKE_REQUIRED_INCLUDES})
+    message(STATUS "Size of SuiteSparse_long is ${SIZEOF_SUITESPARSE_LONG}")
+    if(NOT SIZEOF_SUITESPARSE_LONG EQUAL "8")
+      print_error("Size of 'sunindextype' is 8 but size of 'SuiteSparse_long' is ${SIZEOF_SUITESPARSE_LONG}. KLU cannot be used.")
+    endif()
+  endif()
+
   # Create the KLU_TEST directory
   set(KLU_TEST_DIR ${PROJECT_BINARY_DIR}/KLU_TEST)
   file(MAKE_DIRECTORY ${KLU_TEST_DIR})

doc/shared/RecentChanges.rst

@@ -76,3 +76,6 @@ where not allocated.
 
 Fix bug on LLP64 platforms (like Windows 64-bit) where ``KLU_INDEXTYPE`` could be
 32 bits wide even if ``SUNDIALS_INT64_T`` is defined.
+
+Check if size of ``SuiteSparse_long`` is 8 if the size of ``sunindextype`` is 8
+when using KLU.

src/sunlinsol/klu/sunlinsol_klu.c

@@ -43,18 +43,6 @@
 #define COMMON(S)         (KLU_CONTENT(S)->common)
 #define SOLVE(S)          (KLU_CONTENT(S)->klu_solver)
 
-/*
- * -----------------------------------------------------------------
- * typedef to handle pointer casts from sunindextype to KLU type
- * -----------------------------------------------------------------
- */
-
-#if defined(SUNDIALS_INT64_T)
-#define KLU_INDEXTYPE int64_t
-#else
-#define KLU_INDEXTYPE int
-#endif
-
 /*
  * -----------------------------------------------------------------
  * exported functions
@@ -266,10 +254,9 @@ int SUNLinSolSetup_KLU(SUNLinearSolver S, SUNMatrix A)
   {
     /* Perform symbolic analysis of sparsity structure */
     if (SYMBOLIC(S)) { sun_klu_free_symbolic(&SYMBOLIC(S), &COMMON(S)); }
-    SYMBOLIC(S) =
-      sun_klu_analyze(SUNSparseMatrix_NP(A),
-                      (KLU_INDEXTYPE*)SUNSparseMatrix_IndexPointers(A),
-                      (KLU_INDEXTYPE*)SUNSparseMatrix_IndexValues(A), &COMMON(S));
+    SYMBOLIC(S) = sun_klu_analyze(SUNSparseMatrix_NP(A),
+                                  SUNSparseMatrix_IndexPointers(A),
+                                  SUNSparseMatrix_IndexValues(A), &COMMON(S));
     if (SYMBOLIC(S) == NULL)
     {
       LASTFLAG(S) = SUN_ERR_EXT_FAIL;
@@ -280,8 +267,8 @@ int SUNLinSolSetup_KLU(SUNLinearSolver S, SUNMatrix A)
        Compute the LU factorization of the matrix
        ------------------------------------------------------------*/
     if (NUMERIC(S)) { sun_klu_free_numeric(&NUMERIC(S), &COMMON(S)); }
-    NUMERIC(S) = sun_klu_factor((KLU_INDEXTYPE*)SUNSparseMatrix_IndexPointers(A),
-                                (KLU_INDEXTYPE*)SUNSparseMatrix_IndexValues(A),
+    NUMERIC(S) = sun_klu_factor(SUNSparseMatrix_IndexPointers(A),
+                                SUNSparseMatrix_IndexValues(A),
                                 SUNSparseMatrix_Data(A), SYMBOLIC(S), &COMMON(S));
     if (NUMERIC(S) == NULL)
     {
@@ -294,8 +281,8 @@ int SUNLinSolSetup_KLU(SUNLinearSolver S, SUNMatrix A)
   else
   { /* not the first decomposition, so just refactor */
 
-    retval = sun_klu_refactor((KLU_INDEXTYPE*)SUNSparseMatrix_IndexPointers(A),
-                              (KLU_INDEXTYPE*)SUNSparseMatrix_IndexValues(A),
+    retval = sun_klu_refactor(SUNSparseMatrix_IndexPointers(A),
+                              SUNSparseMatrix_IndexValues(A),
                               SUNSparseMatrix_Data(A), SYMBOLIC(S), NUMERIC(S),
                               &COMMON(S));
     if (retval == 0)
@@ -321,7 +308,7 @@ int SUNLinSolSetup_KLU(SUNLinearSolver S, SUNMatrix A)
     {
       /* Condition number may be getting large.
 	 Compute more accurate estimate */
-      retval = sun_klu_condest((KLU_INDEXTYPE*)SUNSparseMatrix_IndexPointers(A),
+      retval = sun_klu_condest(SUNSparseMatrix_IndexPointers(A),
                                SUNSparseMatrix_Data(A), SYMBOLIC(S), NUMERIC(S),
                                &COMMON(S));
       if (retval == 0)
@@ -333,12 +320,12 @@ int SUNLinSolSetup_KLU(SUNLinearSolver S, SUNMatrix A)
       if (COMMON(S).condest > (ONE / uround_twothirds))
       {
         /* More accurate estimate also says condition number is
-	   large, so recompute the numeric factorization */
+           large, so recompute the numeric factorization */
         sun_klu_free_numeric(&NUMERIC(S), &COMMON(S));
-        NUMERIC(S) =
-          sun_klu_factor((KLU_INDEXTYPE*)SUNSparseMatrix_IndexPointers(A),
-                         (KLU_INDEXTYPE*)SUNSparseMatrix_IndexValues(A),
-                         SUNSparseMatrix_Data(A), SYMBOLIC(S), &COMMON(S));
+        NUMERIC(S) = sun_klu_factor(SUNSparseMatrix_IndexPointers(A),
+                                    SUNSparseMatrix_IndexValues(A),
+                                    SUNSparseMatrix_Data(A), SYMBOLIC(S),
+                                    &COMMON(S));
         if (NUMERIC(S) == NULL)
         {
           LASTFLAG(S) = SUN_ERR_EXT_FAIL;