[lld] Only report "unable to move location counter backward" error for the last run to assignAddresses

lld/ELF/LinkerScript.cpp

@@ -170,8 +170,7 @@ void LinkerScript::expandOutputSection(uint64_t size) {
 void LinkerScript::setDot(Expr e, const Twine &loc, bool inSec) {
   uint64_t val = e().getValue();
   if (val < dot && inSec)
-    error(loc + ": unable to move location counter backward for: " +
-          state->outSec->name);
+    lastSectionWithBackwardsCounter = state->outSec;
 
   // Update to location counter means update to section size.
   if (inSec)
@@ -1327,6 +1326,7 @@ LinkerScript::AddressState::AddressState() {
 // Returns a symbol that has changed its section or value, or nullptr if no
 // symbol has changed.
 const Defined *LinkerScript::assignAddresses() {
+  lastSectionWithBackwardsCounter = nullptr;
   if (script->hasSectionsCommand) {
     // With a linker script, assignment of addresses to headers is covered by
     // allocateHeaders().

lld/ELF/LinkerScript.h

@@ -378,6 +378,10 @@ class LinkerScript final {
 
   // Sections that will be warned/errored by --orphan-handling.
   SmallVector<const InputSectionBase *, 0> orphanSections;
+
+  // If assignAddress() at any point caused the location counter to move
+  // backwards, this will point to the section where this occured.
+  OutputSection *lastSectionWithBackwardsCounter = nullptr;
 };
 
 LLVM_LIBRARY_VISIBILITY extern std::unique_ptr<LinkerScript> script;

lld/ELF/Writer.cpp

@@ -1697,6 +1697,13 @@ template <class ELFT> void Writer<ELFT>::finalizeAddressDependentContent() {
       }
     }
   }
+
+  if (script->lastSectionWithBackwardsCounter) {
+    error(script->lastSectionWithBackwardsCounter->location +
+          ": unable to move location counter backward for: " +
+          script->lastSectionWithBackwardsCounter->name);
+  }
+
   if (!config->relocatable && config->emachine == EM_RISCV)
     riscvFinalizeRelax(pass);