[RuntimeDyld] Don't try to get the contents of sections that don't have any

(e.g. bss sections).

MachO and ELF have been silently letting this pass, but COFFObjectFile contains
an assertion to catch this kind of (ab)use of the getSectionContents, and this
was causing the JIT to crash on COFF objects with BSS sections. This patch
should fix that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250371 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
index b2f017c94cb8f7876b1b4014de202c4d114bfab0..27cd09834df517951269b3b7275d045d842991eb 100644 (file)
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp
@@ -182,8 +182,6 @@ RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
           continue;
         uint64_t SectOffset;
         Check(getOffset(*I, *SI, SectOffset));
-        StringRef SectionData;
-        Check(SI->getContents(SectionData));
         bool IsCode = SI->isText();
         unsigned SectionID =
             findOrEmitSection(Obj, *SI, IsCode, LocalSections);
@@ -568,12 +566,14 @@ unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
   uint8_t *Addr;
   const char *pData = nullptr;
 
-  // In either case, set the location of the unrelocated section in memory,
-  // since we still process relocations for it even if we're not applying them.
-  Check(Section.getContents(data));
-  // Virtual sections have no data in the object image, so leave pData = 0
-  if (!IsVirtual)
+  // If this section contains any bits (i.e. isn't a virtual or bss section),
+  // grab a reference to them.
+  if (!IsVirtual && !IsZeroInit) {
+    // In either case, set the location of the unrelocated section in memory,
+    // since we still process relocations for it even if we're not applying them.
+    Check(Section.getContents(data));
     pData = data.data();
+  }
 
   // Code section alignment needs to be at least as high as stub alignment or
   // padding calculations may by incorrect when the section is remapped to a

diff --git a/test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64 b/test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64.s
similarity index 88%
rename from test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64
rename to test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64.s
index 7029cf437c5e3a38bc29f6cd7f50ea26a1ccecae..fc0f3e8514734e9b3562719590bb298e9767c110 100644 (file)
--- a/test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64
+++ b/test/ExecutionEngine/RuntimeDyld/X86/COFF_x86_64.s
@@ -28,4 +28,7 @@ inst1:
 .Ltmp2:
        .seh_endproc
 
-
+# Make sure the JIT doesn't bail out on BSS sections.
+        .bss
+bss_check:
+        .fill 8, 1, 0