auto merge of #5431 : crabtw/rust/mips-rt, r=brson

Because the PTHREAD_STACK_MIN of my system is larger than default size, I add the stack_sz check to prevent assertion failure.

Besides, libuv has to be modified because some flags are different from other targets. Instead of using hardcoded numbers, I change them to predefined symbols.

By the way, the toolchain I used is http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/editions/lite-edition/mips-gnu-linux

libuv patch: http://people.cs.nctu.edu.tw/~jyyou/rust/mips-uv.patch

Below is the current test result.

* core test

  stackwalk tests can cause segfault so I ignored them.

```
failures:
    io::tests::test_read_be_int_n
    io::tests::test_read_buffer_big_enough
    io::tests::test_read_f32
    io::tests::test_read_write_be
    io::tests::test_read_write_f32
    io::tests::test_read_write_le
    io::tests::test_simple
    io::tests::test_write_empty
    rand::tests::rng_seeded_custom_seed2
    unstable::uvll::test::test_uv_ll_struct_size_addrinfo
    unstable::uvll::test::test_uv_ll_struct_size_uv_timer_t

result: FAILED. 596 passed; 11 failed; 49 ignored
```

* std test:

```
failures:
    time::tests::run_tests

result: FAILED. 330 passed; 1 failed; 21 ignored
```

mk/platform.mk

@@ -239,6 +239,31 @@ CFG_RUN_arm-linux-androideabi=
 CFG_RUN_TARG_arm-linux-androideabi=
 RUSTC_FLAGS_arm-linux-androideabi :=--android-cross-path=$(CFG_ANDROID_CROSS_PATH)
 
+# mips-unknown-linux-gnu configuration
+CC_mips-unknown-linux-gnu=mips-linux-gnu-gcc
+CXX_mips-unknown-linux-gnu=mips-linux-gnu-g++
+CPP_mips-unknown-linux-gnu=mips-linux-gnu-gcc -E
+AR_mips-unknown-linux-gnu=mips-linux-gnu-ar
+CFG_LIB_NAME_mips-unknown-linux-gnu=lib$(1).so
+CFG_LIB_GLOB_mips-unknown-linux-gnu=lib$(1)-*.so
+CFG_LIB_DSYM_GLOB_mips-unknown-linux-gnu=lib$(1)-*.dylib.dSYM
+CFG_GCCISH_CFLAGS_mips-unknown-linux-gnu := -Wall -g -fPIC -mips32r2 -msoft-float -mabi=32
+CFG_GCCISH_CXXFLAGS_mips-unknown-linux-gnu := -fno-rtti
+CFG_GCCISH_LINK_FLAGS_mips-unknown-linux-gnu := -shared -fPIC -g -mips32r2 -msoft-float -mabi=32
+CFG_GCCISH_DEF_FLAG_mips-unknown-linux-gnu := -Wl,--export-dynamic,--dynamic-list=
+CFG_GCCISH_PRE_LIB_FLAGS_mips-unknown-linux-gnu := -Wl,-whole-archive
+CFG_GCCISH_POST_LIB_FLAGS_mips-unknown-linux-gnu := -Wl,-no-whole-archive -Wl,-znoexecstack
+CFG_DEF_SUFFIX_mips-unknown-linux-gnu := .linux.def
+CFG_INSTALL_NAME_mips-unknown-linux-gnu =
+CFG_LIBUV_LINK_FLAGS_mips-unknown-linux-gnu =
+CFG_EXE_SUFFIX_mips-unknown-linux-gnu :=
+CFG_WINDOWSY_mips-unknown-linux-gnu :=
+CFG_UNIXY_mips-unknown-linux-gnu := 1
+CFG_PATH_MUNGE_mips-unknown-linux-gnu := true
+CFG_LDPATH_mips-unknown-linux-gnu :=
+CFG_RUN_mips-unknown-linux-gnu=
+CFG_RUN_TARG_mips-unknown-linux-gnu=
+
 # i686-pc-mingw32 configuration
 CC_i686-pc-mingw32=$(CC)
 CXX_i686-pc-mingw32=$(CXX)

mk/rt.mk

@@ -27,6 +27,7 @@
 LIBUV_FLAGS_i386 = -m32 -fPIC
 LIBUV_FLAGS_x86_64 = -m64 -fPIC
 LIBUV_FLAGS_arm = -fPIC -DANDROID -std=gnu99
+LIBUV_FLAGS_mips = -fPIC -mips32r2 -msoft-float -mabi=32
 
 # when we're doing a snapshot build, we intentionally degrade as many
 # features in libuv and the runtime as possible, to ease portability.
@@ -180,6 +181,10 @@ else
 $$(LIBUV_LIB_$(1)): $$(LIBUV_DEPS)
 	$$(Q)$$(MAKE) -C $$(S)src/libuv/ \
 		CFLAGS="$$(LIBUV_FLAGS_$$(HOST_$(1))) $$(SNAP_DEFINES)" \
+		LDFLAGS="$$(LIBUV_FLAGS_$$(HOST_$(1)))" \
+		CC="$$(CC_$(1))" \
+		CXX="$$(CXX_$(1))" \
+		AR="$$(AR_$(1))" \
 		builddir_name="$$(CFG_BUILD_DIR)/rt/$(1)/libuv" \
 		V=$$(VERBOSE)
 endif

src/libcore/rt/context.rs

@@ -189,6 +189,7 @@ fn initialize_call_frame(regs: &mut Registers, fptr: *c_void, arg: *c_void, sp:
 
     regs[4] = arg as uint;
     regs[29] = sp as uint;
+    regs[25] = fptr as uint;
     regs[31] = fptr as uint;
 }
 

src/librustc/driver/driver.rs

@@ -89,7 +89,7 @@ pub fn default_configuration(sess: Session, +argv0: ~str, input: input) ->
         abi::X86 => (~"little",~"x86",~"32"),
         abi::X86_64 => (~"little",~"x86_64",~"64"),
         abi::Arm => (~"little",~"arm",~"32"),
-        abi::Mips => (~"little",~"arm",~"32")
+        abi::Mips => (~"big",~"mips",~"32")
     };
 
     return ~[ // Target bindings.

src/rt/arch/mips/_context.S

@@ -51,7 +51,6 @@ swap_registers:
         lw $2, 2 * 4($5)
         lw $3, 3 * 4($5)
         lw $4, 4 * 4($5)
-        lw $5, 5 * 4($5)
         lw $6, 6 * 4($5)
         lw $7, 7 * 4($5)
 
@@ -82,6 +81,8 @@ swap_registers:
         lw $30, 30 * 4($5)
         lw $31, 31 * 4($5)
 
+        lw $5, 5 * 4($5)
+
         jr $31
         nop
 .end swap_registers

src/rt/arch/mips/ccall.S

@@ -5,30 +5,39 @@
 
 .text
 
+.align 2
 .globl __morestack
 .hidden __morestack
-.align 2
+.cfi_sections .eh_frame_entry
+.cfi_startproc
 .set nomips16
 .ent __morestack
 __morestack:
         .set noreorder
         .set nomacro
-        move $7, $29
-        move $29, $6
 
-        sw $7, 0($29)
-        sw $31, -4($29)
+        addiu $29, $29, -8
+        sw $31, 4($29)
+        sw $30, 0($29)
 
-        addiu $29, $29, -24
+        .cfi_def_cfa_offset 8
+        .cfi_offset 31, -4
+        .cfi_offset 30, -8
+
+        move $30, $29
+        .cfi_def_cfa_register 30
+
+        move $29, $6
         move $25, $5
         jalr $25
         nop
-        addiu $29, $29, 24
+        move $29, $30
 
-        lw $31, -4($29)
-        lw $7, 0($29)
+        lw $30, 0($29)
+        lw $31, 4($29)
+        addiu $29, $29, 8
 
-        move $29, $7
         jr $31
         nop
 .end __morestack
+.cfi_endproc

src/rt/arch/mips/context.cpp

@@ -40,6 +40,7 @@ void context::call(void *f, void *arg, void *stack)
 
   regs.data[4] = (uint32_t)arg;
   regs.data[29] = (uint32_t)sp;
+  regs.data[25] = (uint32_t)f;
   regs.data[31] = (uint32_t)f;
 
   // Last base pointer on the stack should be 0

src/rt/sync/rust_thread.cpp

@@ -10,6 +10,7 @@
 
 
 #include "rust_thread.h"
+#include <limits.h>
 
 const size_t default_stack_sz = 1024*1024;
 
@@ -41,6 +42,11 @@ rust_thread::start() {
 #if defined(__WIN32__)
    thread = CreateThread(NULL, stack_sz, rust_thread_start, this, 0, NULL);
 #else
+   // PTHREAD_STACK_MIN of some system is larger than default size
+   // so we check stack_sz to prevent assertion failure.
+   if (stack_sz < PTHREAD_STACK_MIN) {
+      stack_sz = PTHREAD_STACK_MIN;
+   }
    pthread_attr_t attr;
    CHECKED(pthread_attr_init(&attr));
    CHECKED(pthread_attr_setstacksize(&attr, stack_sz));