lld: Fix for ld.lld does not accept "AT" syntax for declaring LMA region

AT> lma_region expression allows to specify the memory region
for section load address.

Should fix [upstream LLVM] PR35684.

LLVM review: https://reviews.llvm.org/D41397

Obtained from:	LLVM r322359 by George Rimar

3 files changed, 18 insertions, 0 deletions

diff --git a/contrib/llvm/tools/lld/ELF/LinkerScript.cpp b/contrib/llvm/tools/lld/ELF/LinkerScript.cpp
index 16b306da4654..95848bd20bed 100644
--- a/contrib/llvm/tools/lld/ELF/LinkerScript.cpp
+++ b/contrib/llvm/tools/lld/ELF/LinkerScript.cpp
@@ -667,6 +667,15 @@ void LinkerScript::assignOffsets(OutputSection *Sec) {
     Ctx->LMAOffset = [=] { return Sec->LMAExpr().getValue() - D; };
   }
 
+  if (!Sec->LMARegionName.empty()) {
+    if (MemoryRegion *MR = MemoryRegions.lookup(Sec->LMARegionName)) {
+      uint64_t Offset = MR->Origin - Dot;
+      Ctx->LMAOffset = [=] { return Offset; };
+    } else {
+      error("memory region '" + Sec->LMARegionName + "' not declared");
+    }
+  }
+
   switchTo(Sec);
 
   // The Size previously denoted how many InputSections had been added to this
diff --git a/contrib/llvm/tools/lld/ELF/OutputSections.h b/contrib/llvm/tools/lld/ELF/OutputSections.h
index b2845773e9af..009f45c03333 100644
--- a/contrib/llvm/tools/lld/ELF/OutputSections.h
+++ b/contrib/llvm/tools/lld/ELF/OutputSections.h
@@ -99,6 +99,7 @@ public:
   ConstraintKind Constraint = ConstraintKind::NoConstraint;
   std::string Location;
   std::string MemoryRegionName;
+  std::string LMARegionName;
   bool Noload = false;
 
   template <class ELFT> void finalize();
diff --git a/contrib/llvm/tools/lld/ELF/ScriptParser.cpp b/contrib/llvm/tools/lld/ELF/ScriptParser.cpp
index 4263944981f2..435b3b28f4f2 100644
--- a/contrib/llvm/tools/lld/ELF/ScriptParser.cpp
+++ b/contrib/llvm/tools/lld/ELF/ScriptParser.cpp
@@ -709,6 +709,14 @@ OutputSection *ScriptParser::readOutputSectionDescription(StringRef OutSec) {
   if (consume(">"))
     Cmd->MemoryRegionName = next();
 
+  if (consume("AT")) {
+    expect(">");
+    Cmd->LMARegionName = next();
+  }
+
+  if (Cmd->LMAExpr && !Cmd->LMARegionName.empty())
+    error("section can't have both LMA and a load region");
+
   Cmd->Phdrs = readOutputSectionPhdrs();
 
   if (consume("="))