cmm-notes updates.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>

diff --git a/compiler/cmm/cmm-notes b/compiler/cmm/cmm-notes
index 0852711..e787f18 100644 (file)
--- a/compiler/cmm/cmm-notes
+++ b/compiler/cmm/cmm-notes
@@ -15,14 +15,11 @@ Things to do:
        This will fix the spill before stack check problem but only really as a side\r
        effect. A 'real fix' probably requires making the spiller know about sp checks.\r
 \r
- - There is some silly stuff happening with the Sp. We end up with code like:\r
-   Sp = Sp + 8; R1 = _vwf::I64; Sp = Sp -8\r
-       Seems to be perhaps caused by the issue above but also maybe a optimisation\r
-       pass needed?\r
+   EZY: I don't understand this comment. David Terei, can you clarify?\r
 \r
- - Proc pass all arguments on the stack, adding more code and slowing down things\r
-   a lot. We either need to fix this or even better would be to get rid of\r
-       proc points.\r
+ - Proc points pass all arguments on the stack, adding more code and\r
+   slowing down things a lot. We either need to fix this or even better\r
+   would be to get rid of proc points.\r
 \r
  - CmmInfo.cmmToRawCmm uses Old.Cmm, so it is called after converting Cmm.Cmm to\r
    Old.Cmm. We should abstract it to work on both representations, it needs only to\r
@@ -32,7 +29,7 @@ Things to do:
    we could convert codeGen/StgCmm* clients to the Hoopl's semantics?\r
    It's all deeply unsatisfactory.\r
 \r
- - Improve preformance of Hoopl.\r
+ - Improve performance of Hoopl.\r
 \r
    A nofib comparison of -fasm vs -fnewcodegen nofib compilation parameters\r
    (using the same ghc-cmm branch +libraries compiled by the old codegenerator)\r
@@ -50,6 +47,9 @@ Things to do:
 \r
    So we generate a bit better code, but it takes us longer!\r
 \r
+   EZY: Also importantly, Hoopl uses dramatically more memory than the\r
+   old code generator.\r
+\r
  - Are all blockToNodeList and blockOfNodeList really needed? Maybe we could\r
    splice blocks instead?\r
 \r
@@ -57,7 +57,7 @@ Things to do:
    a block catenation function would be probably nicer than blockToNodeList\r
    / blockOfNodeList combo.\r
 \r
- - loweSafeForeignCall seems too lowlevel. Just use Dataflow. After that\r
+ - lowerSafeForeignCall seems too lowlevel. Just use Dataflow. After that\r
    delete splitEntrySeq from HooplUtils.\r
 \r
  - manifestSP seems to touch a lot of the graph representation. It is\r
@@ -76,6 +76,9 @@ Things to do:
    calling convention, and the code for calling foreign calls is generated\r
 \r
  - AsmCodeGen has a generic Cmm optimiser; move this into new pipeline\r
+   EZY (2011-04-16): The mini-inliner has been generalized and ported,\r
+   but the constant folding and other optimizations need to still be\r
+   ported.\r
 \r
  - AsmCodeGen has post-native-cg branch eliminator (shortCutBranches);\r
    we ultimately want to share this with the Cmm branch eliminator.\r
@@ -113,7 +116,7 @@ Things to do:
  - See "CAFs" below; we want to totally refactor the way SRTs are calculated\r
 \r
  - Pull out Areas into its own module\r
-   Parameterise AreaMap\r
+   Parameterise AreaMap (note there are type synonyms in CmmStackLayout!)\r
    Add ByteWidth = Int\r
    type SubArea    = (Area, ByteOff, ByteWidth) \r
    ByteOff should not be defined in SMRep -- that is too high up the hierarchy\r
@@ -293,8 +296,8 @@ cpsTop:
        insert spills/reloads across \r
           LastCalls, and \r
           Branches to proc-points\r
-     Now sink those reloads:\r
-     - CmmSpillReload.insertLateReloads\r
+     Now sink those reloads (and other instructions):\r
+     - CmmSpillReload.rewriteAssignments\r
      - CmmSpillReload.removeDeadAssignmentsAndReloads\r
 \r
   * CmmStackLayout.stubSlotsOnDeath\r
@@ -344,7 +347,7 @@ to J that way. This is an awkward choice.  (We think that we currently
 never pass variables to join points via arguments.)\r
 \r
 Furthermore, there is *no way* to pass q to J in a register (other\r
-than a paramter register).\r
+than a parameter register).\r
 \r
 What we want is to do register allocation across the whole caboodle.\r
 Then we could drop all the code that deals with the above awkward\r