X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/d57f583f531c3ed96281734e99a3199e0a58ec3f..706dd4584b4002e0d948b81d103dd5c4b70db077:/src/mc/DwarfExpression.cpp

diff --git a/src/mc/DwarfExpression.cpp b/src/mc/DwarfExpression.cpp
index 5e89864124..6cdba68ae1 100644
--- a/src/mc/DwarfExpression.cpp
+++ b/src/mc/DwarfExpression.cpp
@@ -4,33 +4,26 @@
 /* This program is free software; you can redistribute it and/or modify it
  * under the terms of the license (GNU LGPL) which comes with this package. */
 
+#include <cstddef>
 #include <cstdint>
-#include <cstdarg>
 
 #include <dwarf.h>
 #include <elfutils/libdw.h>
 
-#include "mc_object_info.h"
-#include "mc_private.h"
-#include "mc/LocationList.hpp"
-#include "mc/AddressSpace.hpp"
-#include "mc/Frame.hpp"
-#include "mc/ObjectInformation.hpp"
-#include "mc/DwarfExpression.hpp"
-#include "mc_dwarf.hpp"
+#include "src/mc/mc_private.h"
+#include "src/mc/LocationList.hpp"
+#include "src/mc/AddressSpace.hpp"
+#include "src/mc/Frame.hpp"
+#include "src/mc/ObjectInformation.hpp"
+#include "src/mc/DwarfExpression.hpp"
+#include "src/mc/mc_dwarf.hpp"
 
 using simgrid::mc::remote;
 
 namespace simgrid {
 namespace dwarf {
 
-evaluation_error::~evaluation_error() {}
-
-}
-}
-
-namespace simgrid {
-namespace dwarf {
+evaluation_error::~evaluation_error() noexcept(true) {}
 
 void execute(
   const Dwarf_Op* ops, std::size_t n,
@@ -76,22 +69,31 @@ void execute(
     case DW_OP_breg29:
     case DW_OP_breg30:
     case DW_OP_breg31:{
+        // Push register + constant:
         int register_id = simgrid::dwarf::dwarf_register_to_libunwind(
           op->atom - DW_OP_breg0);
         unw_word_t res;
         if (!context.cursor)
-          throw evaluation_error("Missin stack context");
+          throw evaluation_error("Missing stack context");
         unw_get_reg(context.cursor, register_id, &res);
         stack.push(res + op->number);
         break;
       }
 
-      // Push the CFA (Canonical Frame Addresse):
+      // Push the CFA (Canonical Frame Address):
     case DW_OP_call_frame_cfa:
       {
-        // UNW_X86_64_CFA does not return the CFA DWARF expects
-        // (it is a synonym for UNW_X86_64_RSP) so copy the cursor,
-        // unwind it once in order to find the parent SP:
+        /* See 6.4 of DWARF4 (http://dwarfstd.org/doc/DWARF4.pdf#page=140):
+         *
+         * > Typically, the CFA is defined to be the value of the stack
+         * > pointer at the call site in the previous frame (which may be
+         * > different from its value on entry to the current frame).
+         *
+         * We need to unwind the frame in order to get the SP of the parent
+         * frame.
+         *
+         * Warning: the CFA returned by libunwind (UNW_X86_64_RSP, etc.)
+         * is the SP of the *current* frame. */
 
         if (!context.cursor)
           throw evaluation_error("Missint cursor");
@@ -115,7 +117,6 @@ void execute(
       // ***** Constants:
 
       // Short constant literals:
-      // DW_OP_lit15 pushed the 15 on the stack.
     case DW_OP_lit0:
     case DW_OP_lit1:
     case DW_OP_lit2:
@@ -148,6 +149,7 @@ void execute(
     case DW_OP_lit29:
     case DW_OP_lit30:
     case DW_OP_lit31:
+      // Push a literal/constant on the stack:
       stack.push(atom - DW_OP_lit0);
       break;
 
@@ -189,9 +191,8 @@ void execute(
       stack.pop();
       break;
 
-      // Swap the two top-most value of the stack:
     case DW_OP_swap:
-      std::swap(stack.top(), stack.top(1));
+      stack.swap();
       break;
 
       // Duplicate the value under the top of the stack:
@@ -267,66 +268,3 @@ void execute(
 
 }
 }
-
-extern "C" {
-
-/** \brief Find the frame base of a given frame
- *
- *  \param frame
- *  \param unw_cursor
- */
-void *mc_find_frame_base(simgrid::mc::Frame* frame, simgrid::mc::ObjectInformation* object_info,
-                         unw_cursor_t * unw_cursor)
-{
-  simgrid::dwarf::Location location = simgrid::dwarf::resolve(
-                             frame->frame_base, object_info,
-                             unw_cursor, NULL, NULL, -1);
-  if (location.in_memory())
-    return location.address();
-  else if (location.in_register()) {
-    // This is a special case.
-    // The register if not the location of the frame base
-    // (a frame base cannot be located in a register)
-    // Instead, DWARF defines this to mean that the register
-    // contains the address of the frame base.
-    unw_word_t word;
-    unw_get_reg(unw_cursor, location.register_id(), &word);
-    return (void*) word;
-  }
-  else xbt_die("Unexpected location type");
-
-}
-
-void mc_dwarf_location_list_init(
-  simgrid::dwarf::LocationList* list, simgrid::mc::ObjectInformation* info,
-  Dwarf_Die * die, Dwarf_Attribute * attr)
-{
-  list->clear();
-
-  std::ptrdiff_t offset = 0;
-  Dwarf_Addr base, start, end;
-  Dwarf_Op *ops;
-  std::size_t len;
-
-  while (1) {
-
-    offset = dwarf_getlocations(attr, offset, &base, &start, &end, &ops, &len);
-    if (offset == 0)
-      return;
-    else if (offset == -1)
-      xbt_die("Error while loading location list");
-
-    simgrid::dwarf::LocationListEntry entry;
-    entry.expression = simgrid::dwarf::DwarfExpression(ops, ops + len);
-
-    void *base = info->base_address();
-    // If start == 0, this is not a location list:
-    entry.lowpc = start == 0 ? NULL : (char *) base + start;
-    entry.highpc = start == 0 ? NULL : (char *) base + end;
-
-    list->push_back(std::move(entry));
-  }
-
-}
-
-}