--- /dev/null
+/* -----------------------------------------------------------------------------
+ *
+ * (c) The GHC Team, 1998-2004
+ *
+ * Code to perform updates.
+ *
+ * This file is written in a subset of C--, extended with various
+ * features specific to GHC. It is compiled by GHC directly. For the
+ * syntax of .cmm files, see the parser in ghc/compiler/cmm/CmmParse.y.
+ *
+ * ---------------------------------------------------------------------------*/
+
+#include "Cmm.h"
+#include "Updates.h"
+#include "StgLdvProf.h"
+
+/*
+ The update frame return address must be *polymorphic*, that means
+ we have to cope with both vectored and non-vectored returns. This
+ is done by putting the return vector right before the info table, and
+ having a standard direct return address after the info table (pointed
+ to by the return address itself, as usual).
+
+ Each entry in the vector table points to a specialised entry code fragment
+ that knows how to return after doing the update. It would be possible to
+ use a single generic piece of code that simply entered the return value
+ to return, but it's quicker this way. The direct return code of course
+ just does another direct return when it's finished.
+*/
+
+/* on entry to the update code
+ (1) R1 points to the closure being returned
+ (2) Sp points to the update frame
+*/
+
+/* The update fragment has been tuned so as to generate good
+ code with gcc, which accounts for some of the strangeness in the
+ way it is written.
+
+ In particular, the JMP_(ret) bit is passed down and pinned on the
+ end of each branch (there end up being two major branches in the
+ code), since we don't mind duplicating this jump.
+*/
+
+#define UPD_FRAME_ENTRY_TEMPLATE(label,ind_info,ret) \
+ label \
+ { \
+ W_ updatee; \
+ \
+ updatee = StgUpdateFrame_updatee(Sp); \
+ \
+ /* remove the update frame from the stack */ \
+ Sp = Sp + SIZEOF_StgUpdateFrame; \
+ \
+ /* ToDo: it might be a PAP, so we should check... */ \
+ TICK_UPD_CON_IN_NEW(sizeW_fromITBL(%GET_STD_INFO(updatee))); \
+ \
+ UPD_SPEC_IND(updatee, ind_info, R1, jump (ret)); \
+ }
+
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_0_ret,stg_IND_0_info,%RET_VEC(Sp(0),0))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_1_ret,stg_IND_1_info,%RET_VEC(Sp(0),1))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_2_ret,stg_IND_2_info,%RET_VEC(Sp(0),2))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_3_ret,stg_IND_3_info,%RET_VEC(Sp(0),3))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_4_ret,stg_IND_4_info,%RET_VEC(Sp(0),4))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_5_ret,stg_IND_5_info,%RET_VEC(Sp(0),5))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_6_ret,stg_IND_6_info,%RET_VEC(Sp(0),6))
+UPD_FRAME_ENTRY_TEMPLATE(stg_upd_frame_7_ret,stg_IND_7_info,%RET_VEC(Sp(0),7))
+
+#if MAX_VECTORED_RTN > 8
+#error MAX_VECTORED_RTN has changed: please modify stg_upd_frame too.
+#endif
+
+/*
+ Make sure this table is big enough to handle the maximum vectored
+ return size!
+ */
+
+#if defined(PROFILING)
+#define UPD_FRAME_BITMAP 3
+#define UPD_FRAME_WORDS 3
+#else
+#define UPD_FRAME_BITMAP 0
+#define UPD_FRAME_WORDS 1
+#endif
+
+/* this bitmap indicates that the first word of an update frame is a
+ * non-pointer - this is the update frame link. (for profiling,
+ * there's a cost-centre-stack in there too).
+ */
+
+INFO_TABLE_RET( stg_upd_frame,
+ UPD_FRAME_WORDS, UPD_FRAME_BITMAP, UPDATE_FRAME,
+ stg_upd_frame_0_ret,
+ stg_upd_frame_1_ret,
+ stg_upd_frame_2_ret,
+ stg_upd_frame_3_ret,
+ stg_upd_frame_4_ret,
+ stg_upd_frame_5_ret,
+ stg_upd_frame_6_ret,
+ stg_upd_frame_7_ret
+ )
+UPD_FRAME_ENTRY_TEMPLATE(,stg_IND_direct_info,%ENTRY_CODE(Sp(0)))
+
+
+INFO_TABLE_RET( stg_marked_upd_frame,
+ UPD_FRAME_WORDS, UPD_FRAME_BITMAP, UPDATE_FRAME,
+ stg_upd_frame_0_ret,
+ stg_upd_frame_1_ret,
+ stg_upd_frame_2_ret,
+ stg_upd_frame_3_ret,
+ stg_upd_frame_4_ret,
+ stg_upd_frame_5_ret,
+ stg_upd_frame_6_ret,
+ stg_upd_frame_7_ret
+ )
+UPD_FRAME_ENTRY_TEMPLATE(,stg_IND_direct_info,%ENTRY_CODE(Sp(0)))
+
+/*-----------------------------------------------------------------------------
+ Seq frames
+
+ We don't have a primitive seq# operator: it is just a 'case'
+ expression whose scrutinee has either a polymorphic or function type
+ (constructor types can be handled by normal 'case' expressions).
+
+ To handle a polymorphic/function typed seq, we push a SEQ frame on
+ the stack. This is a polymorphic activation record that just pops
+ itself and returns (in a non-vectored way) when entered. The
+ purpose of the SEQ frame is to avoid having to make a polymorphic return
+ point for each polymorphic case expression.
+
+ Another way of looking at it: the SEQ frame turns a vectored return
+ into a direct one.
+ -------------------------------------------------------------------------- */
+
+#if MAX_VECTORED_RTN > 8
+#error MAX_VECTORED_RTN has changed: please modify stg_seq_frame too.
+#endif
+
+INFO_TABLE_RET( stg_seq_frame, 0/* words */, 0/* bitmap */, RET_SMALL,
+ RET_LBL(stg_seq_frame), /* 0 */
+ RET_LBL(stg_seq_frame), /* 1 */
+ RET_LBL(stg_seq_frame), /* 2 */
+ RET_LBL(stg_seq_frame), /* 3 */
+ RET_LBL(stg_seq_frame), /* 4 */
+ RET_LBL(stg_seq_frame), /* 5 */
+ RET_LBL(stg_seq_frame), /* 6 */
+ RET_LBL(stg_seq_frame) /* 7 */
+ )
+{
+ Sp_adj(1);
+ jump %ENTRY_CODE(Sp(0));
+}
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