From 8f2d75d53c18c56e419a4e998699f2b525d68f07 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Mon, 24 Oct 2011 12:33:08 -0700
Subject: [PATCH] switch over sqrt from llvm to c-stack-cdecl, exposing a bug
 in the supported return types of upcall_c_stack

---
 src/comp/back/upcall.rs          |  6 +++++-
 src/comp/middle/trans.rs         | 25 +++++++++++++++++++------
 src/rt/arch/i386/ccall.S         |  4 ++++
 src/rt/rustrt.def.in             |  1 +
 src/test/bench/shootout-nbody.rs |  4 ++--
 5 files changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/comp/back/upcall.rs b/src/comp/back/upcall.rs
index 2589247e2cda..04bdebb04a17 100644
--- a/src/comp/back/upcall.rs
+++ b/src/comp/back/upcall.rs
@@ -5,7 +5,7 @@ import trans::decl_cdecl_fn;
 import middle::trans_common::{T_f32, T_f64, T_fn, T_bool, T_i1, T_i8, T_i32,
                               T_int, T_vec, T_nil, T_opaque_chan_ptr,
                               T_opaque_vec, T_opaque_port_ptr, T_ptr,
-                              T_size_t, T_void};
+                              T_size_t, T_void, T_float};
 import lib::llvm::type_names;
 import lib::llvm::llvm::ModuleRef;
 import lib::llvm::llvm::ValueRef;
@@ -28,6 +28,7 @@ type upcalls =
      dynastack_free: ValueRef,
      alloc_c_stack: ValueRef,
      call_c_stack: ValueRef,
+     call_c_stack_float: ValueRef,
      rust_personality: ValueRef};
 
 fn declare_upcalls(_tn: type_names, tydesc_type: TypeRef,
@@ -77,6 +78,9 @@ fn declare_upcalls(_tn: type_names, tydesc_type: TypeRef,
           call_c_stack: d("call_c_stack",
                           [T_ptr(T_fn([], T_int())), T_ptr(T_i8())],
                           T_int()),
+          call_c_stack_float: d("call_c_stack_float",
+                                [T_ptr(T_fn([], T_int())), T_ptr(T_i8())],
+                                T_float()),
           rust_personality: d("rust_personality", [], T_i32())
          };
 }
diff --git a/src/comp/middle/trans.rs b/src/comp/middle/trans.rs
index 8391f40df47e..c655d7d4b5dc 100644
--- a/src/comp/middle/trans.rs
+++ b/src/comp/middle/trans.rs
@@ -3864,20 +3864,33 @@ fn trans_c_stack_native_call(bcx: @block_ctxt, f: @ast::expr,
         i += 1u;
     }
 
-    // Call.
-    // TODO: Invoke instead.
-    let llrawretval = Call(bcx, ccx.upcalls.call_c_stack,
-                           [llfn, llrawargbundle]);
-
-    // Cast return type.
+    // Determine return type.
     let ret_ty = ty::ty_fn_ret(bcx_tcx(bcx), fn_ty);
     check type_has_static_size(ccx, ret_ty);
     let llretty = type_of(ccx, f.span, ret_ty);
 
+    // Determine which upcall fn to use based on the return type.
+    let upcall_fn = alt lib::llvm::llvm::LLVMGetTypeKind(llretty) {
+      1 | 2 | 3 | 4 | 5 {
+        // LLVMFloatTypeKind, LLVMDoubleTypeKind,
+        // LLVMX86_FP80TypeKind, LLVMFP128TypeKind
+        // LLVMPPC_FP128TypeKind
+        ccx.upcalls.call_c_stack_float
+      }
+
+      _ { ccx.upcalls.call_c_stack }
+    };
+
+    // Call and cast the return type.
+    // TODO: Invoke instead.
+    let llrawretval = Call(bcx, upcall_fn,
+                           [llfn, llrawargbundle]);
     let llretval;
     if lib::llvm::llvm::LLVMGetTypeKind(llretty) as int == 11 { // pointer
         llretval = IntToPtr(bcx, llrawretval, llretty);
     } else {
+        log_err("TruncOrBitCast(", val_str(ccx.tn, llrawretval), ", ",
+                ty_str(ccx.tn, llretty), ")");
         llretval = TruncOrBitCast(bcx, llrawretval, llretty);
     }
 
diff --git a/src/rt/arch/i386/ccall.S b/src/rt/arch/i386/ccall.S
index 44d0c2177360..378ea5e0b67e 100644
--- a/src/rt/arch/i386/ccall.S
+++ b/src/rt/arch/i386/ccall.S
@@ -6,10 +6,14 @@
 // slower.
 #if defined(__APPLE__) || defined(_WIN32)
 .globl _upcall_call_c_stack
+.globl _upcall_call_c_stack_float
 _upcall_call_c_stack:
+_upcall_call_c_stack_float:
 #else
 .globl upcall_call_c_stack
+.globl upcall_call_c_stack_float
 upcall_call_c_stack:
+upcall_call_c_stack_float:
 #endif
     pushl %ebp
     movl %esp,%ebp          // save esp
diff --git a/src/rt/rustrt.def.in b/src/rt/rustrt.def.in
index 3430f77c8927..6b70e2839572 100644
--- a/src/rt/rustrt.def.in
+++ b/src/rt/rustrt.def.in
@@ -65,6 +65,7 @@ task_join
 unsupervise
 upcall_alloc_c_stack
 upcall_call_c_stack
+upcall_call_c_stack_float
 upcall_cmp_type
 upcall_dynastack_alloc
 upcall_dynastack_alloc_2
diff --git a/src/test/bench/shootout-nbody.rs b/src/test/bench/shootout-nbody.rs
index 61122d8e6b48..e6f196f2869c 100644
--- a/src/test/bench/shootout-nbody.rs
+++ b/src/test/bench/shootout-nbody.rs
@@ -1,8 +1,8 @@
 // based on:
 // http://shootout.alioth.debian.org/u32/benchmark.php?test=nbody&lang=java
 
-native "llvm" mod llvm {
-    fn sqrt(n: float) -> float = "sqrt.f64";
+native "c-stack-cdecl" mod llvm = "" {
+    fn sqrt(n: float) -> float;
 }
 
 fn main() {