Merge pull request #439 from hpux735/master

Beginning support for ARMv7 hosts (RasPi, etc.)

stdlib/public/SwiftShims/LibcShims.h

@@ -28,7 +28,11 @@ namespace swift { extern "C" {
 
 // This declaration is not universally correct.  We verify its correctness for
 // the current platform in the runtime code.
+#if defined(__linux__) && defined (__arm__)
+typedef      int __swift_ssize_t;
+#else
 typedef long int __swift_ssize_t;
+#endif
 
 // General utilities <stdlib.h>
 // Memory management functions

stdlib/public/stubs/Stubs.cpp

@@ -216,7 +216,8 @@ extern "C" long double _swift_fmodl(long double lhs, long double rhs) {
 // This implementation is copied here to avoid a new dependency
 // on compiler-rt on Linux.
 // FIXME: rdar://14883575 Libcompiler_rt omits muloti4
-#if __arm64__ || !defined(__APPLE__)
+#if (defined(__APPLE__) && defined(__arm64__)) || \
+    (defined(__linux__) && defined(__x86_64__))
 
 typedef int      ti_int __attribute__ ((mode (TI)));
 extern "C"
@@ -261,6 +262,54 @@ __muloti4(ti_int a, ti_int b, int* overflow)
 
 #endif
 
+#if defined(__linux__) && defined(__arm__)
+// Similar to above, but with mulodi4.  Perhaps this is
+// something that shouldn't be done, and is a bandaid over
+// some other lower-level architecture issue that I'm
+// missing.  Perhaps relevant bug report:
+// FIXME: https://llvm.org/bugs/show_bug.cgi?id=14469
+typedef int      di_int __attribute__ ((mode (DI)));
+extern "C"
+di_int
+__mulodi4(di_int a, di_int b, int* overflow)
+{
+    const int N = (int)(sizeof(di_int) * CHAR_BIT);
+    const di_int MIN = (di_int)1 << (N-1);
+    const di_int MAX = ~MIN;
+    *overflow = 0;
+    di_int result = a * b;
+    if (a == MIN)
+    {
+        if (b != 0 && b != 1)
+            *overflow = 1;
+        return result;
+    }
+    if (b == MIN)
+    {
+        if (a != 0 && a != 1)
+            *overflow = 1;
+        return result;
+    }
+    di_int sa = a >> (N - 1);
+    di_int abs_a = (a ^ sa) - sa;
+    di_int sb = b >> (N - 1);
+    di_int abs_b = (b ^ sb) - sb;
+    if (abs_a < 2 || abs_b < 2)
+        return result;
+    if (sa == sb)
+    {
+        if (abs_a > MAX / abs_b)
+            *overflow = 1;
+    }
+    else
+    {
+        if (abs_a > MIN / -abs_b)
+            *overflow = 1;
+    }
+    return result;
+}
+#endif
+
 // We can't return Float80, but we can receive a pointer to one, so
 // switch the return type and the out parameter on strtold.
 template <typename T>