Expand =/$SYSROOT for INPUT/GROUP script commands

include/eld/ScriptParser/ScriptParser.h

@@ -122,6 +122,11 @@ class ScriptParser final : ScriptLexer {
 
   void addFile(llvm::StringRef Name);
 
+  /// Expand "=" or "$SYSROOT" prefix in Name to sysroot path.
+  /// If sysroot is not set, the marker is stripped and the remaining path is
+  /// used.
+  std::string expandSysrootMarkers(llvm::StringRef Name) const;
+
   /// Reads AS_NEEDED(...) subcommand.
   void readAsNeeded();
 

lib/ScriptParser/ScriptParser.cpp

@@ -739,14 +739,31 @@ void ScriptParser::readAsNeeded() {
   ThisScriptFile.setAsNeeded(false);
 }
 
+std::string ScriptParser::expandSysrootMarkers(StringRef Name) const {
+  StringRef Suffix;
+  if (Name.starts_with("="))
+    Suffix = Name.substr(1);
+  else if (Name.starts_with("$SYSROOT"))
+    Suffix = Name.substr(8); // strlen("$SYSROOT") == 8
+  else
+    return Name.str();
+
+  auto &SearchDirs = ThisConfig.directories();
+  if (SearchDirs.hasSysRoot())
+    return (SearchDirs.sysroot().native() + Suffix).str();
+  return Suffix.str();
+}
+
 void ScriptParser::addFile(StringRef Name) {
   StrToken *InputStrTok = nullptr;
   if (Name.consume_front("-l"))
     InputStrTok = ThisScriptFile.createNameSpecToken(Name.str(),
                                                      ThisScriptFile.asNeeded());
-  else
+  else {
+    std::string ExpandedName = expandSysrootMarkers(Name);
     InputStrTok =
-        ThisScriptFile.createFileToken(Name.str(), ThisScriptFile.asNeeded());
+        ThisScriptFile.createFileToken(ExpandedName, ThisScriptFile.asNeeded());
+  }
   ThisScriptFile.getCurrentStringList()->pushBack(InputStrTok);
 }
 

test/Common/standalone/linkerscript/SysrootExpansion/Inputs/1.c

@@ -0,0 +1 @@
+int foo() { return 1; }

test/Common/standalone/linkerscript/SysrootExpansion/Inputs/group_equals.t

@@ -0,0 +1 @@
+GROUP(=/lib64/lib1.so)

test/Common/standalone/linkerscript/SysrootExpansion/Inputs/main.c

@@ -0,0 +1 @@
+int main() { return 0; }

test/Common/standalone/linkerscript/SysrootExpansion/Inputs/script_equals.t

@@ -0,0 +1 @@
+INPUT(=/lib64/lib1.so)

test/Common/standalone/linkerscript/SysrootExpansion/Inputs/script_sysroot.t

@@ -0,0 +1 @@
+INPUT($SYSROOT/lib64/lib1.so)

test/Common/standalone/linkerscript/SysrootExpansion/SysrootExpansion.test

@@ -0,0 +1,23 @@
+#---SysrootExpansion.test---------------- Linker Script ----------------#
+#BEGIN_COMMENT
+# Validate sysroot expansion for "=" and "$SYSROOT" markers in INPUT/GROUP
+# script commands.
+# When a path starts with "=" or "$SYSROOT", it should be expanded to the
+# sysroot path regardless of where the linker script is located.
+#END_COMMENT
+#START_TEST
+
+RUN: rm -rf %t.dir && mkdir -p %t.dir/lib64
+RUN: %clang %clangopts -o %t.1.o %p/Inputs/1.c -c -fPIC
+RUN: %clang %clangopts -o %t.main.o %p/Inputs/main.c -c
+RUN: %link %linkopts -o %t.dir/lib64/lib1.so -shared %t.1.o
+RUN: %link %linkopts -o %t.out1 --sysroot=%t.dir -T %p/Inputs/script_equals.t %t.main.o --verbose 2>&1 | %filecheck %s --check-prefix=EQUALS
+RUN: %link %linkopts -o %t.out2 --sysroot=%t.dir -T %p/Inputs/script_sysroot.t %t.main.o --verbose 2>&1 | %filecheck %s --check-prefix=SYSROOT
+RUN: %link %linkopts -o %t.out3 --sysroot=%t.dir -T %p/Inputs/group_equals.t %t.main.o --verbose 2>&1 | %filecheck %s --check-prefix=GROUP
+RUN: %not %link %linkopts -o %t.out4 -T %p/Inputs/script_equals.t %t.main.o 2>&1 | %filecheck %s --check-prefix=NOSYSROOT
+#END_TEST
+
+EQUALS: Verbose: Mapping input file '{{.*}}dir/lib64/lib1.so' into memory
+SYSROOT: Verbose: Mapping input file '{{.*}}dir/lib64/lib1.so' into memory
+GROUP: Verbose: Mapping input file '{{.*}}dir/lib64/lib1.so' into memory
+NOSYSROOT: Fatal: cannot read file /lib64/lib1.so