[PATCH] D87486: [ELF] Define a reportRangeError() overload for thunks and tidy up recent PPC64 thunk range errors

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
MaskRay added reviewers: grimar, NeHuang, nemanjai, sfertile, stefanp.
Herald added subscribers: llvm-commits, kbarton, arichardson, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.
MaskRay requested review of this revision.

Prefer `errorOrWarn` to `fatal` for recoverage errors and graceful degradation
when --noinhibit-exec is specified.

Mention the destination symbol, otherwise the diagnostic is not really actionable.
Two errors are not tested but the patch does not intend to add the coverage.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D87486

Files:
  lld/ELF/Relocations.cpp
  lld/ELF/Target.h
  lld/ELF/Thunks.cpp
  lld/test/ELF/ppc64-toc-call-to-pcrel-long-jump.s


Index: lld/test/ELF/ppc64-toc-call-to-pcrel-long-jump.s
===================================================================
--- lld/test/ELF/ppc64-toc-call-to-pcrel-long-jump.s
+++ lld/test/ELF/ppc64-toc-call-to-pcrel-long-jump.s
@@ -10,7 +10,7 @@
 # RUN: llvm-mc -filetype=obj -triple=powerpc64 %s -o %t.o
 # RUN: not ld.lld -T %t.script %t.o -o /dev/null 2>&1 | FileCheck %s
 
-# CHECK: error: R2 save stub branch offset is too large: -268501028
+# CHECK: error: R2 save stub offset is out of range: -268501028 is not in [-33554432, 33554431]; references callee
 
 .section .text_callee, "ax", %progbits
 callee:
Index: lld/ELF/Thunks.cpp
===================================================================
--- lld/ELF/Thunks.cpp
+++ lld/ELF/Thunks.cpp
@@ -896,7 +896,8 @@
   int64_t offset = destination.getVA() - (getThunkTargetSym()->getVA() + 4);
   // The branch offset needs to fit in 26 bits.
   if (!isInt<26>(offset))
-    fatal("R2 save stub branch offset is too large: " + Twine(offset));
+    reportRangeError(buf, offset, 26, destination, "R2 save stub offset");
+  // fatal("R2 save stub branch offset is too large: " + Twine(offset));
   write32(buf + 0, 0xf8410018);                         // std  r2,24(r1)
   write32(buf + 4, 0x48000000 | (offset & 0x03fffffc)); // b    <offset>
 }
@@ -910,7 +911,7 @@
 void PPC64R12SetupStub::writeTo(uint8_t *buf) {
   int64_t offset = destination.getVA() - getThunkTargetSym()->getVA();
   if (!isInt<34>(offset))
-    fatal("offset must fit in 34 bits to encode in the instruction");
+    reportRangeError(buf, offset, 34, destination, "R12 setup stub offset");
   uint64_t paddi = PADDI_R12_NO_DISP | (((offset >> 16) & 0x3ffff) << 32) |
                    (offset & 0xffff);
 
@@ -927,7 +928,8 @@
 void PPC64PCRelPLTStub::writeTo(uint8_t *buf) {
   int64_t offset = destination.getGotPltVA() - getThunkTargetSym()->getVA();
   if (!isInt<34>(offset))
-    fatal("offset must fit in 34 bits to encode in the instruction");
+    reportRangeError(buf, offset, 34, destination,
+                     "PC-relative PLT stub offset");
   uint64_t pld =
       PLD_R12_NO_DISP | (((offset >> 16) & 0x3ffff) << 32) | (offset & 0xffff);
 
Index: lld/ELF/Target.h
===================================================================
--- lld/ELF/Target.h
+++ lld/ELF/Target.h
@@ -229,6 +229,8 @@
 
 void reportRangeError(uint8_t *loc, const Relocation &rel, const Twine &v,
                       int64_t min, uint64_t max);
+void reportRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym,
+                      const Twine &msg);
 
 // Make sure that V can be represented as an N bit signed integer.
 inline void checkInt(uint8_t *loc, int64_t v, int n, const Relocation &rel) {
@@ -260,8 +262,6 @@
           " is not aligned to " + Twine(n) + " bytes");
 }
 
-void checkRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym, const Twine &msg);
-
 // Endianness-aware read/write.
 inline uint16_t read16(const void *p) {
   return llvm::support::endian::read16(p, config->endianness);
Index: lld/ELF/Relocations.cpp
===================================================================
--- lld/ELF/Relocations.cpp
+++ lld/ELF/Relocations.cpp
@@ -113,13 +113,13 @@
               ", " + Twine(max).str() + "]" + hint);
 }
 
-void elf::checkRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym,
-                          const Twine &msg) {
+void elf::reportRangeError(uint8_t *loc, int64_t v, int n, const Symbol &sym,
+                           const Twine &msg) {
   ErrorPlace errPlace = getErrorPlace(loc);
   std::string hint;
-  if (!sym.isLocal())
+  if (!sym.getName().empty())
     hint = "; references " + lld::toString(sym) + getDefinedLocation(sym);
-  errorOrWarn(errPlace.loc + msg + " out of range: " + Twine(v) +
+  errorOrWarn(errPlace.loc + msg + " is out of range: " + Twine(v) +
               " is not in [" + Twine(llvm::minIntN(n)) + ", " +
               Twine(llvm::maxIntN(n)) + "]" + hint);
 }


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