[ExecutionEngine] Correct the size of a write in a COFF i386 relocation

We want to be writing a 32bit value, so we should be writing 4 bytes
instead of 2.

Patch by Alex Langford <apl@fb.com>.

Differential Revision: https://reviews.llvm.org/D38872

llvm-svn: 315964

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFI386.h b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFI386.h
index 901f778..76c8f95 100644 (file)
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFI386.h
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/Targets/RuntimeDyldCOFFI386.h
@@ -209,7 +209,7 @@ public:
       DEBUG(dbgs() << "\t\tOffset: " << RE.Offset
                    << " RelType: IMAGE_REL_I386_SECREL Value: " << RE.Addend
                    << '\n');
-      writeBytesUnaligned(RE.Addend, Target, 2);
+      writeBytesUnaligned(RE.Addend, Target, 4);
       break;
     default:
       llvm_unreachable("unsupported relocation type");

diff --git a/llvm/test/ExecutionEngine/RuntimeDyld/X86/COFF_i386.s b/llvm/test/ExecutionEngine/RuntimeDyld/X86/COFF_i386.s
index ddf154e..869df79 100644 (file)
--- a/llvm/test/ExecutionEngine/RuntimeDyld/X86/COFF_i386.s
+++ b/llvm/test/ExecutionEngine/RuntimeDyld/X86/COFF_i386.s
@@ -49,11 +49,6 @@ __imp__ExitProcess:
        .long "_ExitProcess@4"                  // IMAGE_REL_I386_DIR32
 # rtdyld-check: *{4}__imp__ExitProcess = 0xffffffff
 
-       .global string
-       .align 1
-string:
-       .asciz "Hello World!\n"
-
        .global relocations
 relocations:
 rel5:
@@ -63,8 +58,8 @@ rel6:
 # rtdyld-check: *{2}rel6 = 1
        .secidx __imp__OutputDebugStringA       // IMAGE_REL_I386_SECTION
 rel7:
-# rtdyld-check: *{4}rel7 = relocations - section_addr(COFF_i386.s.tmp.obj, .data)
-       .secrel32 relocations                   // IMAGE_REL_I386_SECREL
+# rtdyld-check: *{4}rel7 = string - section_addr(COFF_i386.s.tmp.obj, .data)
+       .secrel32 string                        // IMAGE_REL_I386_SECREL
 
 # Test that addends work.
 rel8:
@@ -79,3 +74,12 @@ rel10:
 rel11:
 # rtdyld-check: *{4}rel11 = string - section_addr(COFF_i386.s.tmp.obj, .data) + 1
        .long string@SECREL32+1                 // IMAGE_REL_I386_SECREL
+
+# We explicitly add padding to put string outside of the 16bit address space
+# (absolute and as an offset from .data), so that relocations involving
+# 32bit addresses / offsets are not accidentally truncated to 16 bits.
+       .space 65536
+       .global string
+       .align 1
+string:
+       .asciz "Hello World!\n"