[NFC][sanitizer] Swap qsort_r and qsort code

To simplify future review.

Author: vitalybuka

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

@@ -9949,6 +9949,57 @@ INTERCEPTOR(int, getentropy, void *buf, SIZE_T buflen) {
 #define INIT_GETENTROPY
 #endif
 
+#if SANITIZER_INTERCEPT_QSORT_R
+typedef int (*qsort_r_compar_f)(const void *, const void *, void *);
+static THREADLOCAL qsort_r_compar_f qsort_r_compar;
+static THREADLOCAL SIZE_T qsort_r_size;
+static int wrapped_qsort_r_compar(const void *a, const void *b, void *arg) {
+  COMMON_INTERCEPTOR_UNPOISON_PARAM(3);
+  COMMON_INTERCEPTOR_INITIALIZE_RANGE(a, qsort_r_size);
+  COMMON_INTERCEPTOR_INITIALIZE_RANGE(b, qsort_r_size);
+  return qsort_r_compar(a, b, arg);
+}
+
+INTERCEPTOR(void, qsort_r, void *base, SIZE_T nmemb, SIZE_T size,
+            qsort_r_compar_f compar, void *arg) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, qsort_r, base, nmemb, size, compar, arg);
+  // Run the comparator over all array elements to detect any memory issues.
+  if (nmemb > 1) {
+    for (SIZE_T i = 0; i < nmemb - 1; ++i) {
+      void *p = (void *)((char *)base + i * size);
+      void *q = (void *)((char *)base + (i + 1) * size);
+      COMMON_INTERCEPTOR_UNPOISON_PARAM(3);
+      compar(p, q, arg);
+    }
+  }
+  qsort_r_compar_f old_compar = qsort_r_compar;
+  SIZE_T old_size = qsort_r_size;
+  // Handle qsort_r() implementations that recurse using an
+  // interposable function call:
+  bool already_wrapped = compar == wrapped_qsort_r_compar;
+  if (already_wrapped) {
+    // This case should only happen if the qsort() implementation calls itself
+    // using a preemptible function call (e.g. the FreeBSD libc version).
+    // Check that the size and comparator arguments are as expected.
+    CHECK_NE(compar, qsort_r_compar);
+    CHECK_EQ(qsort_r_size, size);
+  } else {
+    qsort_r_compar = compar;
+    qsort_r_size = size;
+  }
+  REAL(qsort_r)(base, nmemb, size, wrapped_qsort_r_compar, arg);
+  if (!already_wrapped) {
+    qsort_r_compar = old_compar;
+    qsort_r_size = old_size;
+  }
+  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, base, nmemb * size);
+}
+#  define INIT_QSORT_R COMMON_INTERCEPT_FUNCTION(qsort_r)
+#else
+#  define INIT_QSORT_R
+#endif
+
 #if SANITIZER_INTERCEPT_QSORT
 // Glibc qsort uses a temporary buffer allocated either on stack or on heap.
 // Poisoned memory from there may get copied into the comparator arguments,
@@ -10011,57 +10062,6 @@ INTERCEPTOR(void, qsort, void *base, SIZE_T nmemb, SIZE_T size,
 #define INIT_QSORT
 #endif
 
-#if SANITIZER_INTERCEPT_QSORT_R
-typedef int (*qsort_r_compar_f)(const void *, const void *, void *);
-static THREADLOCAL qsort_r_compar_f qsort_r_compar;
-static THREADLOCAL SIZE_T qsort_r_size;
-static int wrapped_qsort_r_compar(const void *a, const void *b, void *arg) {
-  COMMON_INTERCEPTOR_UNPOISON_PARAM(3);
-  COMMON_INTERCEPTOR_INITIALIZE_RANGE(a, qsort_r_size);
-  COMMON_INTERCEPTOR_INITIALIZE_RANGE(b, qsort_r_size);
-  return qsort_r_compar(a, b, arg);
-}
-
-INTERCEPTOR(void, qsort_r, void *base, SIZE_T nmemb, SIZE_T size,
-            qsort_r_compar_f compar, void *arg) {
-  void *ctx;
-  COMMON_INTERCEPTOR_ENTER(ctx, qsort_r, base, nmemb, size, compar, arg);
-  // Run the comparator over all array elements to detect any memory issues.
-  if (nmemb > 1) {
-    for (SIZE_T i = 0; i < nmemb - 1; ++i) {
-      void *p = (void *)((char *)base + i * size);
-      void *q = (void *)((char *)base + (i + 1) * size);
-      COMMON_INTERCEPTOR_UNPOISON_PARAM(3);
-      compar(p, q, arg);
-    }
-  }
-  qsort_r_compar_f old_compar = qsort_r_compar;
-  SIZE_T old_size = qsort_r_size;
-  // Handle qsort_r() implementations that recurse using an
-  // interposable function call:
-  bool already_wrapped = compar == wrapped_qsort_r_compar;
-  if (already_wrapped) {
-    // This case should only happen if the qsort() implementation calls itself
-    // using a preemptible function call (e.g. the FreeBSD libc version).
-    // Check that the size and comparator arguments are as expected.
-    CHECK_NE(compar, qsort_r_compar);
-    CHECK_EQ(qsort_r_size, size);
-  } else {
-    qsort_r_compar = compar;
-    qsort_r_size = size;
-  }
-  REAL(qsort_r)(base, nmemb, size, wrapped_qsort_r_compar, arg);
-  if (!already_wrapped) {
-    qsort_r_compar = old_compar;
-    qsort_r_size = old_size;
-  }
-  COMMON_INTERCEPTOR_WRITE_RANGE(ctx, base, nmemb * size);
-}
-#define INIT_QSORT_R COMMON_INTERCEPT_FUNCTION(qsort_r)
-#else
-#define INIT_QSORT_R
-#endif
-
 #if SANITIZER_INTERCEPT_BSEARCH
 typedef int (*bsearch_compar_f)(const void *, const void *);
 static THREADLOCAL bsearch_compar_f bsearch_compar;