Add Compiler_Backend scenario

Some runtime files depend on the compiler backend used, for example GCC
requires us to include gcc specific unwinder code. To allow us to specify
code specific to a compiler backend, a new Compiler_Backend scenario is
added.

Also added a connivence function to tell if we are building for LLVM or not
to improve code readability.

Issue: eng/toolchain/bb-runtimes#20

aarch64/__init__.py

@@ -1,5 +1,5 @@
 # BSP support for ARM64
-from support import Compiler, target_compiler
+from support import using_llvm_compiler
 from support.bsp_sources.archsupport import ArchSupport
 from support.bsp_sources.target import DFBBTarget
 
@@ -117,7 +117,7 @@ def system_ads(self):
 
  # GNAT-LLVM can't build the embedded Morello runtime yet, so we exclude it for
  # the time being.
- if target_compiler() != Compiler.gnat_llvm:
+ if using_llvm_compiler():
  result["embedded"] = "system-xi-arm-nxstack-embedded.ads"
 
  return result

support/__init__.py

@@ -99,3 +99,7 @@ def set_target_compiler(comp):
 
 def target_compiler():
  return _TARGET_COMPILER
+
+
+def using_llvm_compiler():
+ return target_compiler() == Compiler.gnat_llvm

support/bsp_sources/installer.py

@@ -1,4 +1,4 @@
-from support import readfile, getdatafilepath, Compiler, target_compiler
+from support import readfile, getdatafilepath, using_llvm_compiler
 from support.bsp_sources.target import Target
 from support.files_holder import _copy
 
@@ -147,15 +147,11 @@ def _find_rts_sources(self, destination, descriptor):
  break
  if ret is None:
  # gprls did not work, try to find out manually the proper location
- compiler_name_pattern = (
- "%s-llvm-gcc" if target_compiler() == Compiler.gnat_llvm else "%s-gcc"
- )
+ compiler_name_pattern = "%s-llvm-gcc" if using_llvm_compiler() else "%s-gcc"
  compiler = shutil.which(compiler_name_pattern % self.tgt.target)
  if compiler is not None:
  compiler_root = os.path.dirname(os.path.dirname(compiler))
- lib_dir = (
- "gnat-llvm" if target_compiler() == Compiler.gnat_llvm else "gnat"
- )
+ lib_dir = "gnat-llvm" if using_llvm_compiler() else "gnat"
  tentative = os.path.join(
  compiler_root, self.tgt.target, "lib", lib_dir, rts_json_file
  )

support/bsp_sources/target.py

@@ -1,7 +1,7 @@
 import copy
 import sys
 
-from support import readfile, is_string, Compiler, target_compiler
+from support import readfile, is_string, using_llvm_compiler
 from support.files_holder import FilesHolder
 from support.bsp_sources.archsupport import ArchSupport
 from support.rts_sources.profiles import RTSProfiles
@@ -176,7 +176,7 @@ def __init__(self):
  "c_flags": ["-DIN_RTS", "-Dinhibit_libc", "-DLIGHT_RUNTIME"],
  }
  # GNAT-LLVM doesn't support -fcallgraph-info
- if target_compiler() != Compiler.gnat_llvm:
+ if using_llvm_compiler():
  self.build_flags["common_flags"].append("-fcallgraph-info=su,da")
 
  # Add the following compiler switches to runtime.xml for all targets:
@@ -187,7 +187,7 @@ def __init__(self):
  # a hidden runtime dependency that is considered undesirable by many
  # of our customers. strlen is particularly problematic, as its not
  # provided in our light and light-tasking runtimes.
- if target_compiler() == Compiler.gnat:
+ if using_llvm_compiler():
  self.global_compiler_switches = ("-fno-tree-loop-distribute-patterns",)
  else:
  self.global_compiler_switches = ()
@@ -372,7 +372,7 @@ def dump_runtime_xml(self, rts_name, rts):
  blank
  + '"-nostartfiles", "-nolibc", '
  + '"-Wl,--start-group,-lgnarl,-lgnat,-lc,-lgcc,-lgcc_eh,--end-group",'
- if target_compiler() != Compiler.gnat_llvm
+ if using_llvm_compiler()
  else '"-Wl,--start-group,-lgnarl,-lgnat,-lc,-lunwind,--end-group",'
  )
 

support/rts_sources/profiles.py

@@ -5,6 +5,7 @@
 # BSP to actually create a runtime project.
 
 import sys
+from support import using_llvm_compiler
 from support.rts_sources import Rule
 from support.rts_sources.sources import all_scenarios, sources
 
@@ -61,6 +62,8 @@ def light_scenarios(self, profile="light"):
  """Returns the list of directories contained in a base Light runtime"""
  ret = {}
  ret["RTS_Profile"] = profile
+ ret["Compiler_Backend"] = "llvm" if using_llvm_compiler() else "gcc"
+
  ret["Add_Arith64"] = "yes"
  ret["Add_Case_Util:yes"] = "yes"
  ret["Add_Exponent_Float"] = "yes"

support/rts_sources/sources.py

@@ -26,6 +26,7 @@
 all_scenarios = {
  # Main profile
  "RTS_Profile": ["light", "light-tasking", "embedded", "cert"],
+ "Compiler_Backend": ["gcc", "llvm"],
  # Runtime RTP support
  "Is_RTP": ["no", "yes"],
  # CPU architecture
@@ -1523,11 +1524,16 @@
  "srcs": [
  "libgnat/s-excmac__gcc.ads",
  "libgnat/s-excmac__gcc.adb",
- # TODO
- # "libgcc/unwind-dw2-fde.h",
  ],
- # TODO
- # "bb_srcs": ["hie/unwind-dw2-fde-bb.c"],
+ },
+ "full/zcx-dw2-gcc": {
+ "conditions": [
+ "RTS_Profile:embedded",
+ "CPU_Family:!arm",
+ "Compiler_Backend:gcc",
+ ],
+ "srcs": ["libgcc/unwind-dw2-fde.h"],
+ "bb_srcs": ["hie/unwind-dw2-fde-bb.c"],
  },
  "full/zcx-aarch64": {
  "conditions": ["RTS_Profile:embedded", "CPU_Family:aarch64"],