[ELF] .eh_frame: use errorOrWarn for "PC offset is too large"

errorOrWarn is more conventional for recoverable errors. This error
message does not have to use `fatal`, and we try to remove such uses in
parallel code paths.

Author: MaskRay

lld/ELF/SyntheticSections.cpp

@@ -537,9 +537,11 @@ SmallVector<EhFrameSection::FdeData, 0> EhFrameSection::getFdeData() const {
     for (EhSectionPiece *fde : rec->fdes) {
       uint64_t pc = getFdePc(buf, fde->outputOff, enc);
       uint64_t fdeVA = getParent()->addr + fde->outputOff;
-      if (!isInt<32>(pc - va))
-        fatal(toString(fde->sec) + ": PC offset is too large: 0x" +
-              Twine::utohexstr(pc - va));
+      if (!isInt<32>(pc - va)) {
+        errorOrWarn(toString(fde->sec) + ": PC offset is too large: 0x" +
+                    Twine::utohexstr(pc - va));
+        continue;
+      }
       ret.push_back({uint32_t(pc - va), uint32_t(fdeVA - va)});
     }
   }

lld/test/ELF/eh-frame-pcrel-overflow.s

@@ -4,7 +4,9 @@
 # RUN: llvm-mc -filetype=obj -triple=x86_64-pc-linux %p/Inputs/eh-frame-pcrel-overflow.s -o %t1.o
 # RUN: ld.lld --eh-frame-hdr -Ttext=0x90000000 %t.o -o /dev/null
 # RUN: not ld.lld --eh-frame-hdr %t.o %t1.o -o /dev/null 2>&1 | FileCheck %s
+# RUN: ld.lld --eh-frame-hdr %t.o %t1.o -o /dev/null --noinhibit-exec 2>&1 | FileCheck %s --check-prefix=WARN
 # CHECK: error: {{.*}}.o:(.eh_frame): PC offset is too large: 0x90001054
+# WARN: warning: {{.*}}.o:(.eh_frame): PC offset is too large: 0x90001054
 
 .text
 .global _start