ananas: Add shared library support

[zhmu]

Summary

The Ananas Operating System (https://github.com/zhmu/ananas) has shared library support as of commit 57739c0b6ece56dd4872aedf30264ed4b9412c77.

This change adds the necessary settings to clang so that shared executables and libraries can be build correctly.

[ed]

lib/Driver/ToolChains/Ananas.cpp

93–97

This logic is used multiple times. Would it make sense to do something like this?

bool IsShared = Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_pie);
CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(IsShared ? "crtbeginS.o" : "crtbegin.o")));

117–120

CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath(IsShared ? "crtendS.o" : "crtend.o")));

[zhmu]

@ed I tried to keep things as much in line as the other <os>::linker::Construct() functions do. Do you wish to stray from that path?

I actually prefer to keep it like this as it's quite readable already, but YMMV of course :-)

[ed]

In D41500#965157, @zhmu wrote:

@ed I tried to keep things as much in line as the other <os>::linker::Construct() functions do. Do you wish to stray from that path?

I actually prefer to keep it like this as it's quite readable already, but YMMV of course :-)

Agreed. I'll commit this patch later today as is!

lib/Driver/ToolChains/Ananas.cpp

void ananas::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   Args.ClaimAllArgs(options::OPT_emit_llvm);
   // and for "clang -w foo.o -o foo". Other warning options are already
   // handled somewhere else.
   Args.ClaimAllArgs(options::OPT_w);
 
   if (!D.SysRoot.empty())
     CmdArgs.push_back(Args.MakeArgString("--sysroot=" + D.SysRoot));
 
-  // Ananas only supports static linkage for now.
+  if (Args.hasArg(options::OPT_static)) {
     CmdArgs.push_back("-Bstatic");
+  } else {
+    if (Args.hasArg(options::OPT_rdynamic))
+      CmdArgs.push_back("-export-dynamic");
+    if (Args.hasArg(options::OPT_shared)) {
+      CmdArgs.push_back("-Bshareable");
+    } else {
+      Args.AddAllArgs(CmdArgs, options::OPT_pie);
+      CmdArgs.push_back("-dynamic-linker");
+      CmdArgs.push_back("/lib/ld-ananas.so");
+    }
+  }
 
   if (Output.isFilename()) {
     CmdArgs.push_back("-o");
     CmdArgs.push_back(Output.getFilename());
   } else {
     assert(Output.isNothing() && "Invalid output.");
   }
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+    if (!Args.hasArg(options::OPT_shared)) {
       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crt0.o")));
+    }
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crti.o")));
+    if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_pie)) {
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtbeginS.o")));
+    } else {
       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtbegin.o")));
     }
+  }
 
   Args.AddAllArgs(CmdArgs, options::OPT_L);
   ToolChain.AddFilePathLibArgs(Args, CmdArgs);
   Args.AddAllArgs(CmdArgs,
                   {options::OPT_T_Group, options::OPT_e, options::OPT_s,
                    options::OPT_t, options::OPT_Z_Flag, options::OPT_r});
 
   if (D.isUsingLTO())
     AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin, D);
 
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
 
   if (ToolChain.ShouldLinkCXXStdlib(Args))
     ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
     CmdArgs.push_back("-lc");
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
+    if (Args.hasArg(options::OPT_shared) || Args.hasArg(options::OPT_pie))
+      CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtendS.o")));
+    else
       CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtend.o")));
     CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtn.o")));
   }
 
   const char *Exec = Args.MakeArgString(ToolChain.GetLinkerPath());
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
 }
 
 // Ananas - Ananas tool chain which can call as(1) and ld(1) directly.

test/Driver/ananas.c

 // RUN: %clang -no-canonical-prefixes -target x86_64-unknown-ananas -static %s \
 // RUN:   --sysroot=%S/Inputs/ananas-tree -### 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-STATIC %s
 // CHECK-STATIC: ld{{.*}}" "-Bstatic"
 // CHECK-STATIC: crt0.o
 // CHECK-STATIC: crti.o
 // CHECK-STATIC: crtbegin.o
 // CHECK-STATIC: crtend.o
 // CHECK-STATIC: crtn.o
+
+// RUN: %clang -no-canonical-prefixes -target x86_64-unknown-ananas -shared %s \
+// RUN:   --sysroot=%S/Inputs/ananas-tree -### 2>&1 \
+// RUN:   | FileCheck --check-prefix=CHECK-SHARED %s
+// CHECK-SHARED: crti.o
+// CHECK-SHARED: crtbeginS.o
+// CHECK-SHARED: crtendS.o
+// CHECK-SHARED: crtn.o