add --soft-float option

mk/platform.mk

@@ -343,7 +343,7 @@ CFG_PATH_MUNGE_mips-unknown-linux-gnu := true
 CFG_LDPATH_mips-unknown-linux-gnu :=
 CFG_RUN_mips-unknown-linux-gnu=
 CFG_RUN_TARG_mips-unknown-linux-gnu=
-RUSTC_FLAGS_mips-unknown-linux-gnu := --linker=$(CXX_mips-unknown-linux-gnu) --target-cpu mips32r2 --target-feature +mips32r2,+o32
+RUSTC_FLAGS_mips-unknown-linux-gnu := --linker=$(CXX_mips-unknown-linux-gnu) --target-cpu mips32r2 --target-feature +mips32r2,+o32 -Z soft-float
 
 # i686-pc-mingw32 configuration
 CC_i686-pc-mingw32=$(CC)

src/librustc/back/link.rs

@@ -264,6 +264,7 @@ pub mod write {
               session::Default => lib::llvm::CodeGenLevelDefault,
               session::Aggressive => lib::llvm::CodeGenLevelAggressive,
             };
+            let use_softfp = sess.opts.debugging_opts & session::use_softfp != 0;
 
             let tm = do sess.targ_cfg.target_strs.target_triple.with_c_str |T| {
                 do sess.opts.target_cpu.with_c_str |CPU| {
@@ -273,7 +274,8 @@ pub mod write {
                             lib::llvm::CodeModelDefault,
                             lib::llvm::RelocPIC,
                             OptLevel,
-                            true
+                            true,
+                            use_softfp
                         )
                     }
                 }

src/librustc/driver/session.rs

@@ -80,6 +80,7 @@ pub static print_llvm_passes:       uint = 1 << 26;
 pub static no_vectorize_loops:      uint = 1 << 27;
 pub static no_vectorize_slp:        uint = 1 << 28;
 pub static no_prepopulate_passes:   uint = 1 << 29;
+pub static use_softfp:              uint = 1 << 30;
 
 pub fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
     ~[(~"verbose", ~"in general, enable more debug printouts", verbose),
@@ -135,6 +136,7 @@ pub fn debugging_opts_map() -> ~[(~str, ~str, uint)] {
      (~"no-vectorize-slp",
       ~"Don't run LLVM's SLP vectorization passes",
       no_vectorize_slp),
+     (~"soft-float", ~"Generate software floating point library calls", use_softfp),
     ]
 }
 

src/librustc/lib/llvm.rs

@@ -2149,7 +2149,8 @@ pub mod llvm {
                                            Model: CodeGenModel,
                                            Reloc: RelocMode,
                                            Level: CodeGenOptLevel,
-                                           EnableSegstk: bool) -> TargetMachineRef;
+                                           EnableSegstk: bool,
+                                           UseSoftFP: bool) -> TargetMachineRef;
         pub fn LLVMRustDisposeTargetMachine(T: TargetMachineRef);
         pub fn LLVMRustAddAnalysisPasses(T: TargetMachineRef,
                                          PM: PassManagerRef,

src/rustllvm/PassWrapper.cpp

@@ -67,7 +67,8 @@ LLVMRustCreateTargetMachine(const char *triple,
                             CodeModel::Model CM,
                             Reloc::Model RM,
                             CodeGenOpt::Level OptLevel,
-                            bool EnableSegmentedStacks) {
+                            bool EnableSegmentedStacks,
+                            bool UseSoftFloat) {
     std::string Error;
     Triple Trip(Triple::normalize(triple));
     const llvm::Target *TheTarget = TargetRegistry::lookupTarget(Trip.getTriple(),
@@ -84,6 +85,10 @@ LLVMRustCreateTargetMachine(const char *triple,
     Options.FloatABIType =
          (Trip.getEnvironment() == Triple::GNUEABIHF) ? FloatABI::Hard :
                                                         FloatABI::Default;
+    Options.UseSoftFloat = UseSoftFloat;
+    if (UseSoftFloat) {
+        Options.FloatABIType = FloatABI::Soft;
+    }
 
     TargetMachine *TM = TheTarget->createTargetMachine(Trip.getTriple(),
                                                        cpu,