commit c39b97f2112e015cd463ddc434945ba04dba687d
author Petr Hosek <phosek@chromium.org> Sat Nov 03 01:43:25 2018 +0000
committer Petr Hosek <phosek@chromium.org> Sat Nov 03 01:43:25 2018 +0000
tree e9cd97fd2e7f8816a2355be9ad8d7a444b07eab3
parent 4dc4d6eacafd72598afdc73c360f398d140976d3

[Driver] Use -push-/-pop-state and -as-needed for libc++ on Fuchsia

This avoids introducing unnecessary DT_NEEDED entries when using
C++ driver for linking C code or C++ code that doesn't use C++
standard library.

Differential Revision: https://reviews.llvm.org/D53854

llvm-svn: 346064

clang/lib/Driver/ToolChains/Fuchsia.cpp

diff --git a/clang/lib/Driver/ToolChains/Fuchsia.cpp b/clang/lib/Driver/ToolChains/Fuchsia.cpp
index 94441fc..f788f91 100644
--- a/clang/lib/Driver/ToolChains/Fuchsia.cpp
+++ b/clang/lib/Driver/ToolChains/Fuchsia.cpp
@@ -122,13 +122,14 @@
       if (ToolChain.ShouldLinkCXXStdlib(Args)) {
         bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
                                    !Args.hasArg(options::OPT_static);
+        CmdArgs.push_back("--push-state");
+        CmdArgs.push_back("--as-needed");
         if (OnlyLibstdcxxStatic)
-          CmdArgs.push_back("-Bstatic");
+          CmdArgs.push_back("-static");
         ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
-        if (OnlyLibstdcxxStatic)
-          CmdArgs.push_back("-Bdynamic");
+        CmdArgs.push_back("-lm");
+        CmdArgs.push_back("--pop-state");
       }
-      CmdArgs.push_back("-lm");
     }
 
     AddRunTimeLibs(ToolChain, D, CmdArgs, Args);

clang/test/Driver/fuchsia.cpp

diff --git a/clang/test/Driver/fuchsia.cpp b/clang/test/Driver/fuchsia.cpp
index dad16e4..ba9e9b4 100644
--- a/clang/test/Driver/fuchsia.cpp
+++ b/clang/test/Driver/fuchsia.cpp
@@ -15,7 +15,11 @@
 // CHECK-NOT: crti.o
 // CHECK-NOT: crtbegin.o
 // CHECK: "-L[[SYSROOT]]{{/|\\\\}}lib"
-// CHECK: "-lc++" "-lm"
+// CHECK: "--push-state"
+// CHECK: "--as-needed"
+// CHECK: "-lc++"
+// CHECK: "-lm"
+// CHECK: "--pop-state"
 // CHECK: "{{.*[/\\]}}libclang_rt.builtins-x86_64.a"
 // CHECK: "-lc"
 // CHECK-NOT: crtend.o
@@ -29,8 +33,10 @@
 // RUN: %clangxx %s -### --target=x86_64-unknown-fuchsia -static-libstdc++ \
 // RUN:     -fuse-ld=lld 2>&1 \
 // RUN:     | FileCheck %s -check-prefix=CHECK-STATIC
-// CHECK-STATIC: "-Bstatic"
+// CHECK-STATIC: "--push-state"
+// CHECK-STATIC: "--as-needed"
+// CHECK-STATIC: "-static"
 // CHECK-STATIC: "-lc++"
-// CHECK-STATIC: "-Bdynamic"
 // CHECK-STATIC: "-lm"
+// CHECK-STATIC: "--pop-state"
 // CHECK-STATIC: "-lc"