Teach Clang about PIE compilations. This is the first step of PR12380.

First, this patch cleans up the parsing of the PIC and PIE family of
options in the driver. The existing logic failed to claim arguments all
over the place resulting in kludges that marked the options as unused.
Instead actually walk all of the arguments and claim them properly.

We now treat -f{,no-}{pic,PIC,pie,PIE} as a single set, accepting the
last one on the commandline. Previously there were lots of ordering bugs
that could creep in due to the nature of the parsing. Let me know if
folks would like weird things such as "-fPIE -fno-pic" to turn on PIE,
but disable full PIC. This doesn't make any sense to me, but we could in
theory support it.

Options that seem to have intentional "trump" status (-static, -mkernel,
etc) continue to do so and are commented as such.

Next, a -pie-level flag is threaded into the frontend, rigged to
a language option, and handled preprocessor, setting up the appropriate
defines. We'll now have the correct defines when compiling with -fpie.

The one place outside of the preprocessor that was inspecting the PIC
level (as opposed to the relocation model, which is set and handled
separately, yay!) is in the GNU ObjC runtime. I changed it to exactly
preserve existing behavior. If folks want to change its behavior in the
face of PIE, they can do that in a separate patch.

Essentially the only functionality changed here is the preprocessor
defines and bug-fixes to the argument management.

Tests have been updated and extended to test all of this a bit more
thoroughly.

llvm-svn: 154291

3 files changed, 9 insertions, 6 deletions

diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
index a1ba2daf08a..d2ce7c0df63 100644
--- a/clang/include/clang/Basic/LangOptions.def
+++ b/clang/include/clang/Basic/LangOptions.def
@@ -96,7 +96,8 @@ LANGOPT(OptimizeSize      , 1, 0, "__OPTIMIZE_SIZE__ predefined macro")
 LANGOPT(Static            , 1, 0, "__STATIC__ predefined macro (as opposed to __DYNAMIC__)")
 VALUE_LANGOPT(PackStruct  , 32, 0, 
               "default struct packing maximum alignment")
-VALUE_LANGOPT(PICLevel          , 2, 0, "__PIC__ level")
+VALUE_LANGOPT(PICLevel    , 2, 0, "__PIC__ level")
+VALUE_LANGOPT(PIELevel    , 2, 0, "__PIE__ level")
 LANGOPT(GNUInline         , 1, 0, "GNU inline semantics")
 LANGOPT(NoInlineDefine    , 1, 0, "__NO_INLINE__ predefined macro")
 LANGOPT(Deprecated        , 1, 0, "__DEPRECATED predefined macro")
diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
index 18caca6df11..3ab8f834818 100644
--- a/clang/include/clang/Driver/CC1Options.td
+++ b/clang/include/clang/Driver/CC1Options.td
@@ -632,6 +632,8 @@ def fwrapv : Flag<"-fwrapv">,
   HelpText<"Treat signed integer overflow as two's complement">;
 def pic_level : Separate<"-pic-level">,
   HelpText<"Value for __PIC__">;
+def pie_level : Separate<"-pie-level">,
+  HelpText<"Value for __PIE__">;
 def pthread : Flag<"-pthread">,
   HelpText<"Support POSIX threads in generated code">;
 def fpack_struct : Separate<"-fpack-struct">,
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 7875eae4b74..1b6b20c6b31 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -265,8 +265,8 @@ def exported__symbols__list : Separate<"-exported_symbols_list">;
 def e : JoinedOrSeparate<"-e">;
 def fPIC : Flag<"-fPIC">, Group<f_Group>;
 def fno_PIC : Flag<"-fno-PIC">, Group<f_Group>;
-def fPIE : Flag<"-fPIE">, Group<f_Group>, Flags<[NoArgumentUnused]>;
-def fno_PIE : Flag<"-fno-PIE">, Group<f_Group>, Flags<[NoArgumentUnused]>;
+def fPIE : Flag<"-fPIE">, Group<f_Group>;
+def fno_PIE : Flag<"-fno-PIE">, Group<f_Group>;
 def faccess_control : Flag<"-faccess-control">, Group<f_Group>;
 def fallow_unsupported : Flag<"-fallow-unsupported">, Group<f_Group>;
 def faltivec : Flag<"-faltivec">, Group<f_Group>;
@@ -499,8 +499,8 @@ def fpascal_strings : Flag<"-fpascal-strings">, Group<f_Group>;
 def fpch_preprocess : Flag<"-fpch-preprocess">, Group<f_Group>;
 def fpic : Flag<"-fpic">, Group<f_Group>;
 def fno_pic : Flag<"-fno-pic">, Group<f_Group>;
-def fpie : Flag<"-fpie">, Group<f_Group>, Flags<[NoArgumentUnused]>;
-def fno_pie : Flag<"-fno-pie">, Group<f_Group>, Flags<[NoArgumentUnused]>;
+def fpie : Flag<"-fpie">, Group<f_Group>;
+def fno_pie : Flag<"-fno-pie">, Group<f_Group>;
 def fprofile_arcs : Flag<"-fprofile-arcs">, Group<f_Group>;
 def fprofile_generate : Flag<"-fprofile-generate">, Group<f_Group>;
 def framework : Separate<"-framework">, Flags<[LinkerInput]>;
@@ -605,7 +605,7 @@ def march_EQ : Joined<"-march=">, Group<m_Group>;
 def mcmodel_EQ : Joined<"-mcmodel=">, Group<m_Group>;
 def mconstant_cfstrings : Flag<"-mconstant-cfstrings">, Group<clang_ignored_m_Group>;
 def mcpu_EQ : Joined<"-mcpu=">, Group<m_Group>;
-def mdynamic_no_pic : Joined<"-mdynamic-no-pic">, Group<m_Group>, Flags<[NoArgumentUnused]>;
+def mdynamic_no_pic : Joined<"-mdynamic-no-pic">, Group<m_Group>;
 def mfix_and_continue : Flag<"-mfix-and-continue">, Group<clang_ignored_m_Group>;
 def mfloat_abi_EQ : Joined<"-mfloat-abi=">, Group<m_Group>;
 def mfpmath_EQ : Joined<"-mfpmath=">, Group<m_Group>;