X86: handle external tail calls in Windows JIT

If there was a tail call, we would incorrectly handle the relocation.  It would
end up indexing into the array with an incorrect section id.  The symbol was
external to the module, so the Section ID was UNDEFINED (-1).  We would then
index the SmallVector with this ID, triggering an assertion.  Use the Value
rather than the section load address in this case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@275442 91177308-0d34-0410-b5e6-96231b3b80d8

lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFI386.h

@@ -174,8 +174,10 @@ public:
     }
     case COFF::IMAGE_REL_I386_REL32: {
       // 32-bit relative displacement to the target.
-      uint64_t Result = Sections[RE.Sections.SectionA].getLoadAddress() -
-                        Section.getLoadAddress() + RE.Addend - 4 - RE.Offset;
+      uint64_t Result = RE.Sections.SectionA == static_cast<uint32_t>(-1)
+                            ? Value
+                            : Sections[RE.Sections.SectionA].getLoadAddress();
+      Result = Result - Section.getLoadAddress() + RE.Addend - 4 - RE.Offset;
       assert(static_cast<int32_t>(Result) <= INT32_MAX &&
              "relocation overflow");
       assert(static_cast<int32_t>(Result) >= INT32_MIN &&

test/ExecutionEngine/RuntimeDyld/X86/COFF_i386.s

@@ -1,5 +1,5 @@
 // RUN: llvm-mc -triple i686-windows -filetype obj -o %t.obj %s
-// RUN: llvm-rtdyld -triple i686-windows -dummy-extern _OutputDebugStringA@4=0xfffffffe -dummy-extern _ExitProcess@4=0xffffffff -verify -check=%s %t.obj
+// RUN: llvm-rtdyld -triple i686-windows -dummy-extern _printf=0xfffffffd -dummy-extern _OutputDebugStringA@4=0xfffffffe -dummy-extern _ExitProcess@4=0xffffffff -verify -check=%s %t.obj
 
 	.text
 
@@ -13,7 +13,9 @@ rel1:
 	call _function				// IMAGE_REL_I386_REL32
 # rtdyld-check: decode_operand(rel1, 0) = (_function-_main-4-1)
 	xorl %eax, %eax
-	retl
+rel12:
+	jmp _printf
+# rtdyld-check: decode_operand(rel12, 0)[31:0] = (_printf-_main-4-8)
 
 	.def _function
 		.scl 2