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* [SCM] master: Implement libunwind fallback for plt frame. Fixes bug #5259 on x86.
@ 2008-03-12 13:26 mark
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From: mark @ 2008-03-12 13:26 UTC (permalink / raw)
To: frysk-cvs
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- Log -----------------------------------------------------------------
commit cba040e1437a19ae0f0b21d560b13cb6d2091282
Author: Mark Wielaard <mwielaard@redhat.com>
Date: Wed Mar 12 14:22:49 2008 +0100
Implement libunwind fallback for plt frame. Fixes bug #5259 on x86.
frysk-core/frysk/stack/ChangeLog
2008-03-12 Mark Wielaard <mwielaard@redhat.com>
* TestLibFunctionStepFrame.java: Mark only unresolved on x86_64
and ppc. Only check first 24 steps (bug #5917). Tighter check for
main and foo order.
frysk-imports/libunwind/ChangeLog
2007-03-12 Mark Wielaard <mwielaard@redhat.com>
* src/x86/Gstep.c (is_call_instr_at): New function.
(init_stack_based_ret): New function.
(unw_step): Try stack based unwind with call instr, before
fallback to frame pointer.
commit 98ecf5e76797e40a49b0cdcb4c98145ec24059bf
Author: Mark Wielaard <mwielaard@redhat.com>
Date: Wed Mar 12 13:35:53 2008 +0100
Add toString to Frame.
frysk-core/frysk/stack/ChangeLog
2008-03-12 Mark Wielaard <mwielaard@redhat.com>
* Frame.java (toString): New method.
-----------------------------------------------------------------------
Summary of changes:
frysk-core/frysk/stack/ChangeLog | 10 +++
frysk-core/frysk/stack/Frame.java | 20 +++++-
.../frysk/stack/TestLibFunctionStepFrame.java | 28 +++++--
frysk-imports/libunwind/ChangeLog | 7 ++
frysk-imports/libunwind/src/x86/Gstep.c | 77 ++++++++++++++++++++
5 files changed, 132 insertions(+), 10 deletions(-)
First 500 lines of diff:
diff --git a/frysk-core/frysk/stack/ChangeLog b/frysk-core/frysk/stack/ChangeLog
index 8ff178e..47a781f 100644
--- a/frysk-core/frysk/stack/ChangeLog
+++ b/frysk-core/frysk/stack/ChangeLog
@@ -1,3 +1,13 @@
+2008-03-12 Mark Wielaard <mwielaard@redhat.com>
+
+ * TestLibFunctionStepFrame.java: Mark only unresolved on x86_64
+ and ppc. Only check first 24 steps (bug #5917). Tighter check for
+ main and foo order.
+
+2008-03-12 Mark Wielaard <mwielaard@redhat.com>
+
+ * Frame.java (toString): New method.
+
2008-03-10 Mark Wielaard <mwielaard@redhat.com>
* TestLibFunctionStepFrame.java: New test for bug #5259.
diff --git a/frysk-core/frysk/stack/Frame.java b/frysk-core/frysk/stack/Frame.java
index e676008..bee5511 100644
--- a/frysk-core/frysk/stack/Frame.java
+++ b/frysk-core/frysk/stack/Frame.java
@@ -1,6 +1,6 @@
// This file is part of the program FRYSK.
//
-// Copyright 2007, Red Hat Inc.
+// Copyright 2007, 2008, Red Hat Inc.
//
// FRYSK is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by
@@ -41,6 +41,7 @@ package frysk.stack;
import java.io.File;
import java.io.PrintWriter;
+import java.io.StringWriter;
import lib.dwfl.Dwfl;
import lib.dwfl.DwflModule;
@@ -192,7 +193,22 @@ public abstract class Frame {
return "Unknown";
}
}
-
+
+ /**
+ * Returns a plain string representation if this frame.
+ * This is similar to the result of calling <code>toPrint()</code>
+ * with both printParameters and fullPaths set to false.
+ */
+ public String toString() {
+ StringWriter sw = new StringWriter();
+ PrintWriter pw = new PrintWriter(sw);
+ pw.print(this.getClass().getName());
+ pw.print('[');
+ toPrint(pw, false, false);
+ pw.print(']');
+ pw.flush();
+ return sw.toString();
+ }
/**
* Extracts OFFSET:LENGTH bytes of REGISTER storing them from
diff --git a/frysk-core/frysk/stack/TestLibFunctionStepFrame.java b/frysk-core/frysk/stack/TestLibFunctionStepFrame.java
index f1f8c59..d71f5ac 100644
--- a/frysk-core/frysk/stack/TestLibFunctionStepFrame.java
+++ b/frysk-core/frysk/stack/TestLibFunctionStepFrame.java
@@ -67,7 +67,7 @@ public class TestLibFunctionStepFrame
{
public void testStepIntoLibFunctionCall()
{
- if (unresolved(5259))
+ if (unresolvedOnx8664(5259) || unresolvedOnPPC(5259))
return;
String source = Config.getRootSrcDir()
@@ -116,7 +116,7 @@ public class TestLibFunctionStepFrame
// We are at the first plt intruction (for the first time).
long firstPLTAddress = task.getPC();
Frame frame = StackFactory.createFrame(task);
- assertFooAndMainOuterFrames("At first PLT address", frame);
+ assertFooAndMainOuterFrames("First entry in PLT", frame);
// Count your steps. And bail out when there are too many.
int steps = 1;
@@ -125,12 +125,15 @@ public class TestLibFunctionStepFrame
while (currentPC != addressLast && steps < 1000)
{
task.requestUnblock(this);
- assertRunUntilStop("Do step: " + steps);
+ assertRunUntilStop("Do step: "
+ + (seenSecondCall ? "second" : "")
+ + steps);
currentPC = task.getPC();
if (currentPC == address2)
{
seenSecondCall = true;
+ steps = 1;
// When we step we should be at the first PLTAddress again.
// One step and we should be at the first PLT instruction.
task.requestUnblock(this);
@@ -139,14 +142,18 @@ public class TestLibFunctionStepFrame
assertEquals("Second time in PLT", currentPC, firstPLTAddress);
frame = StackFactory.createFrame(task);
- assertFooAndMainOuterFrames("Second time in PLT", frame);
+ assertFooAndMainOuterFrames("Second entry in PLT", frame);
}
- else if (currentPC != addressLast)
+ else if (currentPC != addressLast && steps < 24)
{
+ // Only check first 24
frame = StackFactory.createFrame(task);
- assertFooAndMainOuterFrames("Stepping, #" + steps
+ assertFooAndMainOuterFrames("Stepping "
+ + (seenSecondCall ? "second" : "")
+ + ", #" + steps
+ " through (plt) call", frame);
}
+ steps++;
}
assertTrue("less than a thousand steps", steps < 1000);
@@ -167,6 +174,7 @@ public class TestLibFunctionStepFrame
assertTrue(message + " first inner frame should not be foo or main", ok);
boolean foo_seen = false;
+ boolean main_seen = false;
Frame outer = frame.getOuter();
while (ok && outer != null)
{
@@ -186,7 +194,11 @@ public class TestLibFunctionStepFrame
boolean sym_is_main = name.indexOf("main") != -1;
if (foo_seen && sym_is_main)
- break;
+ {
+ // Hurray done!
+ main_seen = true;
+ break;
+ }
if (! foo_seen && sym_is_main)
{
@@ -199,7 +211,7 @@ public class TestLibFunctionStepFrame
outer = outer.getOuter();
}
- ok = outer != null;
+ ok = ok && foo_seen && main_seen && outer != null;
if (! ok)
printBacktrace(frame);
assertTrue(message
diff --git a/frysk-imports/libunwind/ChangeLog b/frysk-imports/libunwind/ChangeLog
index 6ecc99c..c34bbe9 100644
--- a/frysk-imports/libunwind/ChangeLog
+++ b/frysk-imports/libunwind/ChangeLog
@@ -1,3 +1,10 @@
+2007-03-12 Mark Wielaard <mwielaard@redhat.com>
+
+ * src/x86/Gstep.c (is_call_instr_at): New function.
+ (init_stack_based_ret): New function.
+ (unw_step): Try stack based unwind with call instr, before
+ fallback to frame pointer.
+
2007-01-31 Mark Wielaard <mwielaard@redhat.com>
Fixup libunwind merge.
diff --git a/frysk-imports/libunwind/src/x86/Gstep.c b/frysk-imports/libunwind/src/x86/Gstep.c
index 618b8af..c9083cb 100644
--- a/frysk-imports/libunwind/src/x86/Gstep.c
+++ b/frysk-imports/libunwind/src/x86/Gstep.c
@@ -85,6 +85,72 @@ code_descriptor_trap (struct cursor *c, struct dwarf_loc *eip_loc_pointer)
return 1;
}
+// A CALL instruction starts with 0xFF.
+static int
+is_call_instr_at (struct cursor *c, unw_word_t addr)
+{
+ int ret;
+ unw_word_t instr;
+ ret = dwarf_get (&c->dwarf, DWARF_LOC (addr, 0), &instr);
+ return ret >= 0 && ((instr & 0xff000000) == 0xff000000);
+}
+
+// Checks whether this looks like a plt entry like cursor and returns
+// the stack offset where the return address can be found, or -1 if
+// not detected (also tries to make sure this is the inner most frame).
+// When this function returns positively (zero included) addr will
+// contain the return address.
+static int
+init_stack_based_ret (struct cursor *c, unw_word_t *addr)
+{
+ // See if this looks "clean", everything in actual registers
+ // which indicates this is most likely an inner most frame just
+ // initted.
+ int ret;
+ unw_word_t ip, cfa;
+ ret = dwarf_get (&c->dwarf, c->dwarf.loc[EIP], &ip);
+ if (ret < 0)
+ return ret;
+
+ ret = dwarf_get (&c->dwarf, c->dwarf.loc[ESP], &cfa);
+ if (ret < 0)
+ return ret;
+
+ if (c->sigcontext_format == X86_SCF_NONE
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EAX])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[ECX])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EDX])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EBX])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[ESP])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EBP])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[ESI])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EDI])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EIP])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[EFLAGS])
+ && DWARF_IS_REG_LOC(c->dwarf.loc[TRAPNO])
+ && ip == c->dwarf.ip && cfa == c->dwarf.cfa)
+ {
+ // See if one of the top 3 elements on the stack contains a
+ // return address.
+ int i;
+ for (i = 0; i <= 8; i += 4)
+ {
+ // fprintf(stderr, "trying %d\n", i);
+ ret = dwarf_get (&c->dwarf, DWARF_LOC (c->dwarf.cfa + i, 0), addr);
+ if (ret < 0)
+ return ret;
+
+ // fprintf(stderr, "addr at %d: 0x%x\n", i, *addr);
+ // Sanity check the address, not too low, and must
+ // come from a call instruction.
+ if (*addr > 0 && is_call_instr_at(c, (*addr) - 5))
+ return i;
+ }
+ }
+
+ return -1;
+}
+
PROTECTED int
unw_step (unw_cursor_t *cursor)
{
@@ -92,6 +158,7 @@ unw_step (unw_cursor_t *cursor)
int ret, i;
struct dwarf_loc eip_loc;
int eip_loc_set = 0;
+ unw_word_t addr;
Debug (1, "(cursor=%p, ip=0x%08x)\n", c, (unsigned) c->dwarf.ip);
@@ -202,6 +269,16 @@ unw_step (unw_cursor_t *cursor)
c->dwarf.loc[TRAPNO] = DWARF_NULL_LOC;
c->dwarf.loc[ST0] = DWARF_NULL_LOC;
}
+ else if((ret = init_stack_based_ret(c, &addr)) >= 0)
+ {
+ // fprintf(stderr, "init_stack_based_ret() %d (0x%x)\n", ret, addr);
+ c->dwarf.cfa += ret;
+ c->dwarf.loc[ESP] = DWARF_LOC (c->dwarf.cfa, 0);
+ c->dwarf.loc[EIP] = DWARF_LOC (addr, 0);
+ c->dwarf.ret_addr_column = EIP;
+ c->dwarf.ip = addr;
+ return 1;
+ }
else
{
ret = dwarf_get (&c->dwarf, c->dwarf.loc[EBP], &c->dwarf.cfa);
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2008-03-12 13:26 [SCM] master: Implement libunwind fallback for plt frame. Fixes bug #5259 on x86 mark
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