[PATCH] [10/10] ELF/Aarch64: Add overflow checks for relocation writes

[Rui Ueyama]

================
Comment at: lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp:161
@@ -159,1 +160,3 @@
+                                   int64_t A) {
   int32_t result = (int32_t)((S + A) - P);
+  if (!isInt<27>(result))
----------------
Does the result of S+A-P always fit within int32_t? If not, upper bits are cleared by converting an int64_t result into int32_t, which would result in false test pass in the following isInt<27>() check. Maybe we want to always use int64_t types here to avoid confusion and possible errors.

================
Comment at: lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp:180
@@ -174,1 +179,3 @@
+  if (!isInt<20>(result))
+    return make_out_of_range_reloc_error();
   result &= 0x01FFFFC;
----------------
The same comment applies here.

================
Comment at: lib/ReaderWriter/ELF/AArch64/AArch64RelocationHandler.cpp:356
@@ -342,1 +355,3 @@
+                                                           int64_t A) {
   int32_t result = S + A;
+  if (!isUInt<24>(result))
----------------
Ditto

http://reviews.llvm.org/D8870

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