Stop stack sketch from moving between frame 1-2

Different stack frame sizes, no main RA, %rsp -> stack pointer

Makefile

@@ -7,4 +7,4 @@ clean:
 	rm -f *aux *bbl *bcf *blg *_latexmk *fls *log *out *.run.xml
 
 upload: build
-	scp slides.pdf www.tobast:~/files/oracle18.pdf
+	scp slides.pdf www.tobast:~/files/slides-oopsla19.pdf

README.md

@@ -1,3 +1,4 @@
-# Presentation, Uppsala, 2018-11
+# Slides for OOPSLA19 "Reliable and Fast DWARF-based Stack Unwinding"
 
-Slides for a presentation at Uppsala, related to UPMARC'18
+This repository contains the slides for OOPSLA19 presentation "Reliable and
+Fast DWARF-based Stack Unwinding".

demo.old/demo.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int bar(int x) {
+	printf("'I’m %d; how many? %n\n", x, &x);
+	return x;
+}
+
+int foo() {
+	return bar(3);
+}
+
+int main() {
+	return foo();
+}

demo.old/synth.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+SYNTHESIS_SCRIPT="../../../src/dwarf-synthesis/synthesize_dwarf.sh"
+
+if [ "$#" -lt 1 ] ; then
+    >&2 echo -e "Missing argument: object file.\nUsage: $0 object.o"
+    exit 1
+fi
+
+objfile="$1"
+
+$SYNTHESIS_SCRIPT "$objfile" "$objfile.synth"

demo/.gitignore

@@ -0,0 +1,3 @@
+dwarf-synthesis
+tests/data*
+tests/*.synth

demo/Makefile

@@ -0,0 +1,9 @@
+all:
+	@>&2 echo "Please provide an explicit target"
+	@exit 1
+
+tests/data:
+	dd if=/dev/urandom of="$@" bs=512K count=4
+
+clean:
+	rm -f tests/data.gz tests/gzip.synth

demo/synthesize.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+./dwarf-synthesis/synthesize_dwarf.sh $* 2>/dev/null

demo/zip.c

@@ -0,0 +1,132 @@
+/* zip.c -- compress files to the gzip or pkzip format
+
+   Copyright (C) 1997-1999, 2006-2007, 2009-2018 Free Software Foundation, Inc.
+   Copyright (C) 1992-1993 Jean-loup Gailly
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#include <config.h>
+#include <ctype.h>
+
+#include "tailor.h"
+#include "gzip.h"
+
+local ulg crc;       /* crc on uncompressed file data */
+off_t header_bytes;   /* number of bytes in gzip header */
+
+/* ===========================================================================
+ * Deflate in to out.
+ * IN assertions: the input and output buffers are cleared.
+ *   The variables time_stamp and save_orig_name are initialized.
+ */
+int zip(in, out)
+    int in, out;            /* input and output file descriptors */
+{
+    uch  flags = 0;         /* general purpose bit flags */
+    ush  attr = 0;          /* ascii/binary flag */
+    ush  deflate_flags = 0; /* pkzip -es, -en or -ex equivalent */
+    ulg  stamp;
+
+    ifd = in;
+    ofd = out;
+    outcnt = 0;
+
+    /* Write the header to the gzip file. See algorithm.doc for the format */
+
+    method = DEFLATED;
+    put_byte(GZIP_MAGIC[0]); /* magic header */
+    put_byte(GZIP_MAGIC[1]);
+    put_byte(DEFLATED);      /* compression method */
+
+    if (save_orig_name) {
+        flags |= ORIG_NAME;
+    }
+    put_byte(flags);         /* general flags */
+    if (time_stamp.tv_nsec < 0)
+      stamp = 0;
+    else if (0 < time_stamp.tv_sec && time_stamp.tv_sec <= 0xffffffff)
+      stamp = time_stamp.tv_sec;
+    else
+      {
+        /* It's intended that timestamp 0 generates this warning,
+           since gzip format reserves 0 for something else.  */
+        warning ("file timestamp out of range for gzip format");
+        stamp = 0;
+      }
+    put_long (stamp);
+
+    /* Write deflated file to zip file */
+    crc = updcrc(0, 0);
+
+    bi_init(out);
+    ct_init(&attr, &method);
+    lm_init(level, &deflate_flags);
+
+    put_byte((uch)deflate_flags); /* extra flags */
+    put_byte(OS_CODE);            /* OS identifier */
+
+    if (save_orig_name) {
+        char *p = gzip_base_name (ifname); /* Don't save the directory part. */
+        do {
+            put_byte (*p);
+        } while (*p++);
+    }
+    header_bytes = (off_t)outcnt;
+
+    (void)deflate();
+
+#ifndef NO_SIZE_CHECK
+  /* Check input size
+   * (but not on MSDOS -- diet in TSR mode reports an incorrect file size)
+   */
+    if (ifile_size != -1L && bytes_in != ifile_size) {
+        fprintf(stderr, "%s: %s: file size changed while zipping\n",
+                program_name, ifname);
+    }
+#endif
+
+    /* Write the crc and uncompressed size */
+    put_long(crc);
+    put_long((ulg)bytes_in);
+    header_bytes += 2*4;
+
+    flush_outbuf();
+    return OK;
+}
+
+
+/* ===========================================================================
+ * Read a new buffer from the current input file, perform end-of-line
+ * translation, and update the crc and input file size.
+ * IN assertion: size >= 2 (for end-of-line translation)
+ */
+int file_read(buf, size)
+    char *buf;
+    unsigned size;
+{
+    unsigned len;
+
+    Assert(insize == 0, "inbuf not empty");
+
+    len = read_buffer (ifd, buf, size);
+    if (len == 0) return (int)len;
+    if (len == (unsigned)-1) {
+        read_error();
+    }
+
+    crc = updcrc((uch*)buf, len);
+    bytes_in += (off_t)len;
+    return (int)len;
+}

src/dw_plt

@@ -0,0 +1,7 @@
+30 24 34 FDE pc=004020..004040
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_advance_loc: 6 to 0000000000004026
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_advance_loc: 10 to 0000000000004030
+  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8; DW_OP_breg16 (rip): 0; DW_OP_lit15; DW_OP_and; DW_OP_lit11; DW_OP_ge; DW_OP_lit3; DW_OP_shl; DW_OP_plus)
+  [...]

src/dw_plt_abbr

@@ -0,0 +1,7 @@
+30 24 34 FDE pc=004020..004040
+  DW_CFA_def_cfa_offset: 16
+  DW_CFA_advance_loc: 6 to 0000000000004026
+  DW_CFA_def_cfa_offset: 24
+  DW_CFA_advance_loc: 10 to 0000000000004030
+  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8;
+    DW_OP_breg16 (rip): 0; ...)

src/lowlevellock_backtrace

@@ -0,0 +1,5 @@
+(gdb) backtrace
+#0 0x406c2c in _L_lock_19
+#1 0x406c2c in _L_lock_19
+#2 0x4069c6 in abort
+#3 0x401017 in main

src/lowlevellock_dw.c

@@ -0,0 +1,25 @@
+#define LLL_STUB_UNWIND_INFO_START
+    ".section    .eh_frame,\"a\",@progbits\n"
+"5:\t"    ".long    7f-6f            # Length of Common Information Entry\n"
+"6:\t"    ".long    0x0              # CIE Identifier Tag\n\t"
+    ".byte    0x1                    # CIE Version\n\t"
+    ".ascii \"zR\\0\"                # CIE Augmentation\n\t"
+    ".uleb128 0x1                    # CIE Code Alignment Factor\n\t"
+    ".sleb128 -4                     # CIE RA Column\n\t"
+    ".byte    0x8                    # Augmentation size\n\t"
+    ".uleb128 0x1                    # FDE Encoding (pcrel sdata4)\n\t"
+    ".byte    0x1b                   # DW_CFA_def_cfa\n\t"
+    ".byte    0xc\n\t"
+    ".uleb128 0x4\n\t"
+    ".uleb128 0x0\n\t"
+    ".align 4\n"
+"7:\t"    ".long    17f-8f           # FDE Length\n"
+"8:\t"    ".long    8b-5b            # FDE CIE offset\n\t"
+    ".long    1b-.                   # FDE initial location\n\t"
+    ".long    4b-1b                  # FDE address range\n\t"
+    ".uleb128 0x0                    # Augmentation size\n\t"
+    ".byte    0x16                   # DW_CFA_val_expression\n\t"
+    ".uleb128 0x8\n\t"
+    ".uleb128 10f-9f\n"
+"9:\t"    ".byte    0x78             # DW_OP_breg8\n\t"
+    ".sleb128 3b-1b\n"

src/lowlevellock_dw_extr.c

@@ -0,0 +1,24 @@
+    .section    .eh_frame,"a",@progbits
+5:  .long    7f-6f       # Length of Common Information Entry
+6:  .long    0x0         # CIE Identifier Tag
+    .byte    0x1         # CIE Version
+    .ascii "zR\\0"       # CIE Augmentation
+    .uleb128 0x1         # CIE Code Alignment Factor
+    .sleb128 -4          # CIE RA Column
+    .byte    0x8         # Augmentation size
+    .uleb128 0x1         # FDE Encoding (pcrel sdata4)
+    .byte    0x1b        # DW_CFA_def_cfa
+    .byte    0xc
+    .uleb128 0x4
+    .uleb128 0x0
+    .align 4
+7:  .long    17f-8f      # FDE Length
+8:  .long    8b-5b       # FDE CIE offset
+    .long    1b-.        # FDE initial location
+    .long    4b-1b       # FDE address range
+    .uleb128 0x0         # Augmentation size
+    .byte    0x16        # DW_CFA_val_expression
+    .uleb128 0x8
+    .uleb128 10f-9f
+9:  .byte    0x78        # DW_OP_breg8
+    .sleb128 3b-1b

src/main_cfi.s

@@ -0,0 +1,10 @@
+main:
+.cfi_startproc
+pushq	%rbp
+.cfi_def_cfa_offset 16
+.cfi_offset 6, -16
+movq	%rsp, %rbp
+.cfi_def_cfa_register 6
+subq	$32, %rsp
+movl    %edi, -20(%rbp)
+movq    %rsi, -32(%rbp)

src/main_cfi_full.s

@@ -0,0 +1,27 @@
+main:
+.LFB6:
+        .cfi_startproc
+        pushq   %rbp
+        .cfi_def_cfa_offset 16
+        .cfi_offset 6, -16
+        movq    %rsp, %rbp
+        .cfi_def_cfa_register 6
+        subq    $32, %rsp
+        movl    %edi, -20(%rbp)
+        movq    %rsi, -32(%rbp)
+        movq    -32(%rbp), %rax
+        addq    $8, %rax
+        movq    (%rax), %rax
+        movq    %rax, %rdi
+        call    atoi@PLT
+        movl    %eax, -4(%rbp)
+        movl    -4(%rbp), %eax
+        leave
+        .cfi_def_cfa 7, 8
+        ret
+        .cfi_endproc
+.LFE6:
+        .size   main, .-main
+        .ident  "GCC: (GNU) 9.2.0"
+        .section        .note.GNU-stack,"",@progbits
+