Add support for Thumb targets, make Linux-armv7 default to thumbv7.

Requires clang change
apple/swift-clang@b071a9a

Author: tienex

CMakeLists.txt

@@ -400,7 +400,7 @@ if("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
     set(SWIFT_PRIMARY_VARIANT_ARCH_default "x86_64")
   # FIXME: This only matches ARMv7l (by far the most common variant).
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l")
-    configure_sdk_unix(LINUX "Linux" "linux" "linux" "armv7" "armv7-unknown-linux-gnueabihf")
+    configure_sdk_unix(LINUX "Linux" "linux" "linux" "armv7" "thumbv7-unknown-linux-gnueabihf")
     set(SWIFT_HOST_VARIANT_ARCH "armv7")
     set(SWIFT_PRIMARY_VARIANT_ARCH_default "armv7")
   elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "aarch64")

lib/Basic/LangOptions.cpp

@@ -110,6 +110,7 @@ std::pair<bool, bool> LangOptions::setTarget(llvm::Triple triple) {
   // Set the "arch" target configuration.
   switch (Target.getArch()) {
   case llvm::Triple::ArchType::arm:
+  case llvm::Triple::ArchType::thumb:
     addTargetConfigOption("arch", "arm");
     break;
   case llvm::Triple::ArchType::aarch64:

lib/Driver/ToolChains.cpp

@@ -1052,6 +1052,8 @@ toolchains::GenericUnix::constructInvocation(const LinkJobAction &job,
         break;
       case llvm::Triple::arm:
       case llvm::Triple::armeb:
+      case llvm::Triple::thumb:
+      case llvm::Triple::thumbeb:
         // Avoid emitting R_ARM_REL32 which is not supported by shared objects
         // on ELF targets.
         Arguments.push_back("-Wl,-Bsymbolic");

stdlib/public/runtime/CMakeLists.txt

@@ -75,9 +75,9 @@ foreach(sdk ${SWIFT_CONFIGURED_SDKS})
   if("${sdk}" STREQUAL "LINUX" OR "${sdk}" STREQUAL "FREEBSD")
     foreach(arch ${SWIFT_SDK_${sdk}_ARCHITECTURES})
       if ("${sdk}" STREQUAL "LINUX" AND "${arch}" STREQUAL "armv7")
-        # Handle special case for ARM on Linux.
+        # Handle special case for ARM/Thumb on Linux.
         # FIXME: Find a more elegant way to handle this case.
-        foreach(subarch armv7;armv7l)
+        foreach(subarch armv7;armv7l;thumbv7;thumbv7l)
           set(arch_subdir "${SWIFT_SDK_${sdk}_LIB_SUBDIR}/${subarch}")
 
           configure_file(

test/1_stdlib/FloatingPointIR.swift

@@ -42,6 +42,9 @@ func testConstantFoldFloatLiterals() {
 // armv7: call void @{{.*}}_TF15FloatingPointIR13acceptFloat32FSfT_(float 1.000000e+00)
 // armv7: call void @{{.*}}_TF15FloatingPointIR13acceptFloat64FSdT_(double 1.000000e+00)
 
+// thumbv7: call void @{{.*}}_TF15FloatingPointIR13acceptFloat32FSfT_(float 1.000000e+00)
+// thumbv7: call void @{{.*}}_TF15FloatingPointIR13acceptFloat64FSdT_(double 1.000000e+00)
+
 // armv7k: call void @{{.*}}_TF15FloatingPointIR13acceptFloat32FSfT_(float 1.000000e+00)
 // armv7k: call void @{{.*}}_TF15FloatingPointIR13acceptFloat64FSdT_(double 1.000000e+00)