1.0.41.27: ppc: Calling convention fixes for assembly-routines calling static-funs.

[sbcl.git] / src / runtime / ppc-assem.S

diff --git a/src/runtime/ppc-assem.S b/src/runtime/ppc-assem.S
index 974f339..318d576 100644 (file)
--- a/src/runtime/ppc-assem.S
+++ b/src/runtime/ppc-assem.S
@@ -21,7 +21,7 @@
                        .align 3 @ \
 _##x:
 
-#define GFUNCDEF(x)    .globl _/**/x @ \
+#define GFUNCDEF(x)    .globl _ ## x @ \
        FUNCDEF(x)
 #else
 #define FUNCDEF(x)     .text ; \
@@ -574,23 +574,75 @@ CSYMBOL(funcallable_instance_tramp) = . + 1
        mtctr reg_LIP
        bctr
        SET_SIZE(funcallable_instance_tramp)
-       
-       GFUNCDEF(fun_end_breakpoint_trap)
-       .long 0
-       SET_SIZE(fun_end_breakpoint_trap)
-
-       GFUNCDEF(fun_end_breakpoint)
-       .long 0
-       SET_SIZE(fun_end_breakpoint)
-
+\f
+       /* The fun_end_breakpoint support here is considered by the
+       authors of the other $ARCH-assem.S files to be magic, and it
+       is.  It is a small fragment of code that is copied into a heap
+       code-object when needed, and contains an LRA object, code to
+       convert a single-value return to unknown-values format, and a
+       trap_FunEndBreakpoint. */
        GFUNCDEF(fun_end_breakpoint_guts)
-       .long 0
-       SET_SIZE(fun_end_breakpoint_guts)
-
-       GFUNCDEF(fun_end_breakpoint_end)
-       .long 0
-       SET_SIZE(fun_end_breakpoint_end)
+       .globl CSYMBOL(fun_end_breakpoint_trap)
+       .globl CSYMBOL(fun_end_breakpoint_end)
+
+       /* Due to pointer verification in MAKE-LISP-OBJ on GENCGC
+       targets, which includes PPC, this must include its header data
+       (the offset from the start of the code-object to the LRA).
+       The code-object header is five words, there are two words of
+       constants, and the instruction space is doubleword-aligned,
+       making an offset of eight.  This is header data for a widetag,
+       so shift left eight bits and add. */
+       .long RETURN_PC_HEADER_WIDETAG + 0x800
+
+       /* We are receiving unknown multiple values, thus must deal
+       with the single-value and multiple-value cases separately. */
+       b fun_end_breakpoint_multiple_values
+       nop
 
+       /* Compute the correct value for reg_CODE based on the LRA.
+       This is a "simple" matter of subtracting a constant from
+       reg_LRA (where the LRA is stored by the return sequence) to
+       obtain a tagged pointer to the enclosing code component.  Both
+       values are tagged OTHER_POINTER_LOWTAG, so we just have to
+       account for the eight words (see calculation for
+       RETURN_PC_HEADER_WIDETAG, above) between the two addresses.
+       Restoring reg_CODE doesn't appear to be strictly necessary
+       here, but let's observe the niceties.*/
+       addi reg_CODE, reg_LRA, -32
+
+       /* Multiple values are stored relative to reg_OCFP, which we
+       set to be the current top-of-stack. */
+       mr reg_OCFP, reg_CSP
+
+       /* Reserve a save location for the one value we have. */
+       addi reg_CSP, reg_CSP, 4
+
+       /* Record the number of values we have as a FIXNUM. */
+       li reg_NARGS, 4
+
+       /* Blank the remaining arg-passing registers. */
+       mr reg_A1, reg_NULL
+       mr reg_A2, reg_NULL
+       mr reg_A3, reg_NULL
+
+       /* And branch to our trap. */
+       b CSYMBOL(fun_end_breakpoint_trap)
+
+fun_end_breakpoint_multiple_values:
+       /* Compute the correct value for reg_CODE.  See the
+       explanation for the single-value case, above. */
+       addi reg_CODE, reg_LRA, -32
+
+       /* The actual magic trap. */
+CSYMBOL(fun_end_breakpoint_trap):
+       twllei  reg_ZERO, trap_FunEndBreakpoint
+
+       /* Finally, the debugger needs to know where the end of the
+       fun_end_breakpoint_guts are, so that it may calculate its size
+       in order to populate out a suitably-sized code object. */
+CSYMBOL(fun_end_breakpoint_end):
+       SET_SIZE(fun_end_breakpoint_guts)
+\f
 
        GFUNCDEF(ppc_flush_cache_line)
        dcbf 0,REG(3)