rt: Make 32-bit morestack compatible with fastcc

diff --git a/src/rt/arch/i386/morestack.S b/src/rt/arch/i386/morestack.S
index 7481ce3afd0461d7a1a4e2b13e1a6d80569b218d..6d67984c91b9b7d3089a2ba8888873b4f2dd21e1 100644 (file)
--- a/src/rt/arch/i386/morestack.S
+++ b/src/rt/arch/i386/morestack.S
@@ -62,14 +62,19 @@ MORESTACK:
 #endif
 
        // NB: This can be called with the fastcc convention so we
-       // have to preserve any argument registers we want to use
+       // have to preserve any argument registers
 
        // NB: __morestack is called misaligned by 4 bytes, i.e.
        // subl $4, %esp would get us to a normal alignment
 
+       subl $44,%esp
+
+       // Save fastcc arguments
+       movl %ecx, 28(%esp)
+       movl %edx, 24(%esp)
+
        // FIXME (1226): main is compiled with the split-stack prologue,
        // causing it to call __morestack, so we have to jump back out
-       subl $28,%esp
        calll RUST_GET_TASK
        testl %eax,%eax
        jz .L$bail
@@ -88,13 +93,13 @@ MORESTACK:
        // for the unwinder
        leal 20(%ebp), %eax
        movl %eax, -4(%ebp)
-       
+
        // The arguments to rust_new_stack2
-       movl 40(%esp),%eax  // Size of stack arguments
+       movl 56(%esp),%eax  // Size of stack arguments
        movl %eax,20(%esp)
-       leal 48(%esp),%eax // Address of stack arguments
+       leal 64(%esp),%eax // Address of stack arguments
        movl %eax,16(%esp)
-       movl 36(%esp),%eax // The amount of stack needed
+       movl 52(%esp),%eax // The amount of stack needed
        movl %eax,12(%esp)
        movl $0, 8(%esp)   // Out pointer
 
@@ -111,11 +116,15 @@ MORESTACK:
        movl %eax,(%esp)
        call UPCALL_CALL_C
 
-       movl 32(%esp),%eax          // Grab the return pointer.
+       movl 48(%esp),%eax          // Grab the return pointer.
        inc  %eax    // Skip past the ret instruction in the parent fn
 
+       // Restore fastcc arguments
+       movl 28(%esp), %ecx
+       movl 24(%esp), %edx
+
        movl 8(%esp),%esp          // Switch stacks.
-       call *%eax             // Re-enter the function that called us.
+       call *%eax                 // Re-enter the function that called us.
 
        // Now the function that called us has returned, so we need to delete the
        // old stack space.
@@ -155,7 +164,7 @@ MORESTACK:
        movl 32(%esp),%eax
        inc %eax
        
-       addl $28, %esp
+       addl $44, %esp
        popl %ebp
        addl $4+8,%esp