diff --git a/lld/ELF/Config.h b/lld/ELF/Config.h
--- a/lld/ELF/Config.h
+++ b/lld/ELF/Config.h
@@ -226,6 +226,7 @@
   bool warnCommon;
   bool warnMissingEntry;
   bool warnSymbolOrdering;
+  bool whyExtract;
   bool writeAddends;
   bool zCombreloc;
   bool zCopyreloc;
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -1203,6 +1203,10 @@
   setUnresolvedSymbolPolicy(args);
   config->Power10Stub = getP10StubOpt(args);
 
+  config->whyExtract = args.hasArg(OPT_why_extract);
+  if (config->whyExtract)
+    lld::outs() << "reference\textracted\tsymbol\n";
+
   if (opt::Arg *arg = args.getLastArg(OPT_eb, OPT_el)) {
     if (arg->getOption().matches(OPT_eb))
       config->optEB = true;
@@ -1694,13 +1698,17 @@
 }
 
 // Force Sym to be entered in the output.
-static void handleUndefined(Symbol *sym) {
+static void handleUndefined(Symbol *sym, const char *option) {
   // Since a symbol may not be used inside the program, LTO may
   // eliminate it. Mark the symbol as "used" to prevent it.
   sym->isUsedInRegularObj = true;
 
-  if (sym->isLazy())
-    sym->fetch();
+  if (!sym->isLazy())
+    return;
+  sym->fetch();
+  if (config->whyExtract)
+    lld::outs() << option << '\t' << toString(sym->file) << '\t'
+                << toString(*sym) << '\n';
 }
 
 // As an extension to GNU linkers, lld supports a variant of `-u`
@@ -1723,7 +1731,7 @@
   }
 
   for (Symbol *sym : syms)
-    handleUndefined(sym);
+    handleUndefined(sym, "--undefined-glob");
 }
 
 static void handleLibcall(StringRef name) {
@@ -2244,7 +2252,7 @@
 
   // If an entry symbol is in a static archive, pull out that file now.
   if (Symbol *sym = symtab->find(config->entry))
-    handleUndefined(sym);
+    handleUndefined(sym, "--entry");
 
   // Handle the `--undefined-glob <pattern>` options.
   for (StringRef pat : args::getStrings(args, OPT_undefined_glob))
diff --git a/lld/ELF/Options.td b/lld/ELF/Options.td
--- a/lld/ELF/Options.td
+++ b/lld/ELF/Options.td
@@ -492,6 +492,8 @@
     "Force load of all members in a static library",
     "Do not force load of all members in a static library (default)">;
 
+def why_extract: FF<"why-extract">, HelpText<"Report why archive members are extracted">;
+
 defm wrap : Eq<"wrap", "Redirect symbol references to __wrap_symbol and "
                        "__real_symbol references to symbol">,
             MetaVarName<"<symbol>">;
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -321,6 +321,12 @@
   message(toString(sym->file) + s + sym->getName());
 }
 
+static void printWhyExtract(const InputFile *reference,
+                            const InputFile &extracted, const Symbol &sym) {
+  lld::outs() << toString(reference) << '\t' << toString(&extracted) << '\t'
+              << toString(sym) << '\n';
+}
+
 void elf::maybeWarnUnorderableSymbol(const Symbol *sym) {
   if (!config->warnSymbolOrdering)
     return;
@@ -533,6 +539,9 @@
                    file->groupId < other.file->groupId;
     fetch();
 
+    if (config->whyExtract)
+      printWhyExtract(other.file, *file, *this);
+
     // We don't report backward references to weak symbols as they can be
     // overridden later.
     //
@@ -742,7 +751,10 @@
     return;
   }
 
+  const InputFile *oldFile = file;
   other.fetch();
+  if (config->whyExtract)
+    printWhyExtract(oldFile, *file, *this);
 }
 
 void Symbol::resolveShared(const SharedSymbol &other) {
diff --git a/lld/test/ELF/why-extract.s b/lld/test/ELF/why-extract.s
new file mode 100644
--- /dev/null
+++ b/lld/test/ELF/why-extract.s
@@ -0,0 +1,65 @@
+# REQUIRES: x86
+
+# RUN: rm -rf %t && split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/main.s -o %t/main.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a.s -o %t/a.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/a_b.s -o %t/a_b.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %t/b.s -o %t/b.o
+# RUN: llvm-ar rc %t/a.a %t/a.o
+# RUN: llvm-ar rc %t/a_b.a %t/a_b.o
+# RUN: llvm-ar rc %t/b.a %t/b.o
+# RUN: cd %t
+
+# RUN: ld.lld main.o a_b.a b.a -o /dev/null --why-extract | FileCheck %s --match-full-lines --strict-whitespace
+
+#      CHECK:reference	extracted	symbol
+# CHECK-NEXT:main.o	a_b.a(a_b.o)	a
+# CHECK-NEXT:a_b.a(a_b.o)	b.a(b.o)	b()
+
+# RUN: ld.lld main.o a_b.a b.a -o /dev/null --no-demangle --why-extract | FileCheck %s --check-prefix=MANGLED
+
+# MANGLED: a_b.a(a_b.o)	b.a(b.o)	_Z1bv
+
+# RUN: ld.lld main.o a.a b.a -o /dev/null -u _Z1bv --why-extract | FileCheck %s --check-prefix=UNDEFINED
+
+## We insert -u symbol before processing other files, so its name is <internal>.
+## This is not ideal.
+# UNDEFINED: <internal>	b.a(b.o)	b()
+
+# RUN: ld.lld main.o a.a b.a -o /dev/null --undefined-glob '_Z1b*' --why-extract | FileCheck %s --check-prefix=UNDEFINED_GLOB
+
+# UNDEFINED_GLOB: --undefined-glob	b.a(b.o)	b()
+
+# RUN: ld.lld main.o a.a b.a -o /dev/null -e _Z1bv --why-extract | FileCheck %s --check-prefix=ENTRY
+
+# ENTRY: --entry	b.a(b.o)	b()
+
+# RUN: ld.lld main.o b.a -o /dev/null -T a.lds --why-extract | FileCheck %s --check-prefix=SCRIPT
+
+# SCRIPT: <internal>	b.a(b.o)	b()
+
+# RUN: ld.lld main.o --start-lib a_b.o b.o --end-lib -o /dev/null --why-extract | FileCheck %s --check-prefix=LAZY
+
+# LAZY: main.o	a_b.o	a
+# LAZY: a_b.o	b.o	b()
+
+#--- main.s
+.globl _start
+_start:
+  call a
+
+#--- a.s
+.globl a
+a:
+
+#--- a_b.s
+.globl a
+a:
+  call _Z1bv
+
+#--- b.s
+.globl _Z1bv
+_Z1bv:
+
+#--- a.lds
+a = _Z1bv;