[RuntimeDyld, PowerPC] Fix check for external symbols when detecting reloction overflow

The PowerPC part of processRelocationRef currently assumes that external
symbols can be identified by checking for SymType == SymbolRef::ST_Unknown.
This is actually incorrect in some cases, causing relocation overflows to
be mis-detected. The correct check is to test whether Value.SymbolName
is null.

Includes test case. Note that it is a bit tricky to replicate the exact
condition that triggers the bug in a test case. The one included here
seems to fail reliably (before the fix) across different operating
system versions on Power, but it still makes a few assumptions (called
out in the test case comments).

Also add ppc64le platform name to the supported list in the lit.local.cfg
files for the MCJIT and OrcMCJIT directories, since those tests were
currently not run at all.

Fixes PR32650.

Reviewer: hfinkel

Differential Revision: https://reviews.llvm.org/D33402



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303637 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 8 deletions

diff --git a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
index c4b9b961885..777db30dd53 100644
--- a/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
+++ b/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldELF.cpp
@@ -1324,12 +1324,12 @@ RuntimeDyldELF::processRelocationRef(
       Obj.getPlatformFlags(AbiVariant);
       AbiVariant &= ELF::EF_PPC64_ABI;
       // A PPC branch relocation will need a stub function if the target is
-      // an external symbol (Symbol::ST_Unknown) or if the target address
+      // an external symbol (Value.SymbolName set) or if the target address
       // is not within the signed 24-bits branch address.
       SectionEntry &Section = Sections[SectionID];
       uint8_t *Target = Section.getAddressWithOffset(Offset);
       bool RangeOverflow = false;
-      if (SymType != SymbolRef::ST_Unknown) {
+      if (!Value.SymbolName) {
         if (AbiVariant != 2) {
           // In the ELFv1 ABI, a function call may point to the .opd entry,
           // so the final symbol value is calculated based on the relocation
@@ -1348,15 +1348,12 @@ RuntimeDyldELF::processRelocationRef(
         // If it is within 26-bits branch range, just set the branch target
         if (SignExtend64<26>(delta) == delta) {
           RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
-          if (Value.SymbolName)
-            addRelocationForSymbol(RE, Value.SymbolName);
-          else
-            addRelocationForSection(RE, Value.SectionID);
+          addRelocationForSection(RE, Value.SectionID);
         } else {
           RangeOverflow = true;
         }
       }
-      if (SymType == SymbolRef::ST_Unknown || RangeOverflow) {
+      if (Value.SymbolName || RangeOverflow) {
         // It is an external symbol (SymbolRef::ST_Unknown) or within a range
         // larger than 24-bits.
         StubMap::const_iterator i = Stubs.find(Value);
@@ -1412,7 +1409,7 @@ RuntimeDyldELF::processRelocationRef(
                             RelType, 0);
           Section.advanceStubOffset(getMaxStubSize());
         }
-        if (SymType == SymbolRef::ST_Unknown) {
+        if (Value.SymbolName) {
           // Restore the TOC for external calls
           if (AbiVariant == 2)
             writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)