[BOLT] Detect incorrect update of dynamic relocations (#89681)

When we rewrite dynamic relocations, there could be cases where they
reference code locations inside functions that were rewritten. When this
happens, we need to precisely map old address to a new one. Until we can
reliably perform the mapping, detect such condition and issue an error
refusing to write a broken binary.

Author: maksfb

bolt/lib/Rewrite/RewriteInstance.cpp

@@ -5432,6 +5432,17 @@ uint64_t RewriteInstance::getNewFunctionOrDataAddress(uint64_t OldAddress) {
   if (BD && BD->isMoved())
     return BD->getOutputAddress();
 
+  if (const BinaryFunction *BF =
+          BC->getBinaryFunctionContainingAddress(OldAddress)) {
+    if (BF->isEmitted()) {
+      BC->errs() << "BOLT-ERROR: unable to get new address corresponding to "
+                    "input address 0x"
+                 << Twine::utohexstr(OldAddress) << " in function " << *BF
+                 << ". Consider adding this function to --skip-funcs=...\n";
+      exit(1);
+    }
+  }
+
   return 0;
 }
 

bolt/test/X86/indirect-goto-pie.test

@@ -0,0 +1,16 @@
+# Check that llvm-bolt fails to process PIC binaries with computed goto, as the
+# support is not there yet for correctly updating dynamic relocations
+# referencing code inside functions.
+
+REQUIRES: x86_64-linux
+
+RUN: %clang %S/Inputs/indirect_goto.c -o %t -fpic -pie -Wl,-q
+RUN: not llvm-bolt %t -o %t.bolt --relocs=1 --print-cfg --print-only=main \
+RUN:   |& FileCheck %s
+
+# Check that processing works if main() is skipped.
+RUN: llvm-bolt %t -o %t.bolt --relocs=1 --skip-funcs=main
+
+CHECK:  jmpq    *%rax # UNKNOWN CONTROL FLOW
+
+CHECK: BOLT-ERROR: unable to get new address

bolt/test/X86/shrinkwrapping-do-not-pessimize.s

@@ -53,6 +53,6 @@ end_if_1:
   .size _start, .-_start
 
   .data
-rel:  .quad end_if_1
+rel:  .quad _start
 
 # CHECK:   BOLT-INFO: Shrink wrapping moved 0 spills inserting load/stores and 0 spills inserting push/pops