[ELF] - Do not segfault when doing logical and/or operations on symbols that have no output sections.

[grimar]

Summary

Previously we would crash on samples from testcase,
because were trying to access zero pointer to output section.

[grimar]

• Addressed review comment.

[grimar]

ping

[ruiu]

test/ELF/linkerscript/early-assign-symbol.s

10–15 ↗

(On Diff #109291)

What is the difference between these two tests? If they are testing the same thing, remove one of them. Unnecessary tests do harm than good. Please do not add tests for "just in case".

[grimar]

test/ELF/linkerscript/early-assign-symbol.s

10–15 ↗

(On Diff #109291)

First checks | and second checks & operator.

Them are implemented via bitAnd() and bitOr() (both use getValue() changed in patch atm),
so I think we want to check both flows ?

[ruiu]

test/ELF/linkerscript/early-assign-symbol.s

10–15 ↗

(On Diff #109291)

No, as long as one test covers new code, adding more test is mostly redundant. Just like attempting new code concise and clean, you want to try to make tests concise.

[grimar]

• Addressed review comment.

[ruiu]

LGTM

lld/trunk/ELF/LinkerScript.cpp

 using namespace llvm::ELF;
 using namespace llvm::object;
 using namespace llvm::support::endian;
 using namespace lld;
 using namespace lld::elf;
 
 LinkerScript *elf::Script;
 
-uint64_t ExprValue::getValue() const {
-  if (Sec) {
-    if (OutputSection *OS = Sec->getOutputSection())
-      return alignTo(Sec->getOffset(Val) + OS->Addr, Alignment);
-    error(Loc + ": unable to evaluate expression: input section " + Sec->Name +
-          " has no output section assigned");
-  }
+static uint64_t getOutputSectionVA(SectionBase *InputSec, StringRef Loc) {
+  if (OutputSection *OS = InputSec->getOutputSection())
+    return OS->Addr;
+  error(Loc + ": unable to evaluate expression: input section " +
+        InputSec->Name + " has no output section assigned");
+  return 0;
+
+uint64_t ExprValue::getValue() const {
+  if (Sec)
+    return alignTo(Sec->getOffset(Val) + getOutputSectionVA(Sec, Loc),
+                   Alignment);
   return alignTo(Val, Alignment);
 }
 
 uint64_t ExprValue::getSecAddr() const {
   if (Sec)
-    return Sec->getOffset(0) + Sec->getOutputSection()->Addr;
+    return Sec->getOffset(0) + getOutputSectionVA(Sec, Loc);
   return 0;
 }
 
 static SymbolBody *addRegular(SymbolAssignment *Cmd) {
   Symbol *Sym;
   uint8_t Visibility = Cmd->Hidden ? STV_HIDDEN : STV_DEFAULT;
   std::tie(Sym, std::ignore) = Symtab->insert(Cmd->Name, /*Type*/ 0, Visibility,
                                               /*CanOmitFromDynSym*/ false,

lld/trunk/test/ELF/linkerscript/early-assign-symbol.s

 # REQUIRES: x86
 # RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
 
 # RUN: echo "SECTIONS { aaa = 1 + ABSOLUTE(foo - 1); .text  : { *(.text*) } }" > %t1.script
 # RUN: not ld.lld -o %t --script %t1.script %t.o 2>&1 | FileCheck %s
 
 # RUN: echo "SECTIONS { aaa = ABSOLUTE(foo - 1) + 1; .text  : { *(.text*) } }" > %t2.script
 # RUN: not ld.lld -o %t --script %t2.script %t.o 2>&1 | FileCheck %s
 
+# RUN: echo "SECTIONS { aaa = foo | 1; .text  : { *(.text*) } }" > %t3.script
+# RUN: not ld.lld -o %t --script %t3.script %t.o 2>&1 | FileCheck %s
+
 # CHECK: error: {{.*}}.script:1: unable to evaluate expression: input section .text has no output section assigned
 
 .section .text
 .globl foo
 foo: