6l/8l: emit DWARF frame info.
R=rsc, ken2, r
CC=golang-dev
https://golang.org/cl/2151044
diff --git a/src/cmd/6l/l.h b/src/cmd/6l/l.h
index 22f266f..b8f47fc 100644
--- a/src/cmd/6l/l.h
+++ b/src/cmd/6l/l.h
@@ -95,6 +95,7 @@
Prog* dlink;
Prog* pcond; /* work on this */
vlong pc;
+ int32 spadj;
int32 line;
short as;
char ft; /* oclass cache */
@@ -102,7 +103,7 @@
uchar mark; /* work on these */
uchar back;
- char width; /* fake for DATA */
+ char width; /* fake for DATA */
char mode; /* 16, 32, or 64 */
};
struct Auto
@@ -397,7 +398,7 @@
void cflush(void);
void ckoff(Sym*, int32);
Prog* copyp(Prog*);
-vlong cpos(void);
+vlong cpos(void);
double cputime(void);
void datblk(int32, int32);
void deadcode(void);
@@ -463,3 +464,9 @@
#pragma varargck type "R" int
#pragma varargck type "A" int
#pragma varargck argpos diag 1
+
+/* Used by ../ld/dwarf.c */
+enum
+{
+ DWARFREGSP = 7
+};
diff --git a/src/cmd/6l/pass.c b/src/cmd/6l/pass.c
index ea33512..d207e74 100644
--- a/src/cmd/6l/pass.c
+++ b/src/cmd/6l/pass.c
@@ -692,7 +692,7 @@
p->from.type = D_INDIR+D_GS;
p->from.offset = tlsoffset+0;
p->to.type = D_CX;
-
+
if(debug['K']) {
// 6l -K means check not only for stack
// overflow but stack underflow.
@@ -843,6 +843,7 @@
p->as = AADJSP;
p->from.type = D_CONST;
p->from.offset = autoffset;
+ p->spadj = autoffset;
if(q != P)
q->pcond = p;
}
@@ -903,26 +904,32 @@
case APUSHL:
case APUSHFL:
deltasp += 4;
+ p->spadj = 4;
continue;
case APUSHQ:
case APUSHFQ:
deltasp += 8;
+ p->spadj = 8;
continue;
case APUSHW:
case APUSHFW:
deltasp += 2;
+ p->spadj = 2;
continue;
case APOPL:
case APOPFL:
deltasp -= 4;
+ p->spadj = -4;
continue;
case APOPQ:
case APOPFQ:
deltasp -= 8;
+ p->spadj = -8;
continue;
case APOPW:
case APOPFW:
deltasp -= 2;
+ p->spadj = -2;
continue;
case ARET:
break;
@@ -937,7 +944,7 @@
p->as = AADJSP;
p->from.type = D_CONST;
p->from.offset = -autoffset;
-
+ p->spadj = -autoffset;
p = appendp(p);
p->as = ARET;
}
@@ -954,6 +961,7 @@
q->from = zprg.from;
q->from.type = D_CONST;
q->from.offset = -autoffset;
+ q->spadj = -autoffset;
q->to = zprg.to;
continue;
}
diff --git a/src/cmd/8l/l.h b/src/cmd/8l/l.h
index e3b53f2..489f1ae 100644
--- a/src/cmd/8l/l.h
+++ b/src/cmd/8l/l.h
@@ -95,6 +95,7 @@
Prog* dlink;
Prog* pcond; /* work on this */
int32 pc;
+ int32 spadj;
int32 line;
short as;
char width; /* fake for DATA */
@@ -346,7 +347,7 @@
void cflush(void);
void ckoff(Sym*, int32);
Prog* copyp(Prog*);
-vlong cpos(void);
+vlong cpos(void);
double cputime(void);
void datblk(int32, int32, int32);
void diag(char*, ...);
@@ -412,3 +413,9 @@
#pragma varargck type "P" Prog*
#pragma varargck type "R" int
#pragma varargck type "A" int
+
+/* Used by ../ld/dwarf.c */
+enum
+{
+ DWARFREGSP = 4
+};
diff --git a/src/cmd/8l/pass.c b/src/cmd/8l/pass.c
index bf09fd9..f59ccdb 100644
--- a/src/cmd/8l/pass.c
+++ b/src/cmd/8l/pass.c
@@ -392,10 +392,10 @@
for(p = firstp; p != P; p = p->link) {
if(HEADTYPE == 10) { // Windows
// Convert
- // op n(GS), reg
+ // op n(GS), reg
// to
// MOVL 0x2C(FS), reg
- // op n(reg), reg
+ // op n(reg), reg
// The purpose of this patch is to fix some accesses
// to extern register variables (TLS) on Windows, as
// a different method is used to access them.
@@ -770,6 +770,7 @@
p->as = AADJSP;
p->from.type = D_CONST;
p->from.offset = autoffset;
+ p->spadj = autoffset;
if(q != P)
q->pcond = p;
}
@@ -792,18 +793,22 @@
case APUSHL:
case APUSHFL:
deltasp += 4;
+ p->spadj = 4;
continue;
case APUSHW:
case APUSHFW:
deltasp += 2;
+ p->spadj = 2;
continue;
case APOPL:
case APOPFL:
deltasp -= 4;
+ p->spadj = -4;
continue;
case APOPW:
case APOPFW:
deltasp -= 2;
+ p->spadj = -2;
continue;
case ARET:
break;
@@ -822,6 +827,7 @@
q->as = AADJSP;
q->from.type = D_CONST;
q->from.offset = -autoffset;
+ p->spadj = -autoffset;
}
continue;
@@ -836,6 +842,7 @@
q->from = zprg.from;
q->from.type = D_CONST;
q->from.offset = -autoffset;
+ p->spadj = -autoffset;
q->to = zprg.to;
continue;
}
diff --git a/src/cmd/ld/dwarf.c b/src/cmd/ld/dwarf.c
index add9277..6e440d0 100644
--- a/src/cmd/ld/dwarf.c
+++ b/src/cmd/ld/dwarf.c
@@ -10,7 +10,7 @@
#include "../ld/macho.h"
/*
- * Offsets and sizes of the .debug_* sections in the cout file.
+ * Offsets and sizes of the debug_* sections in the cout file.
*/
static vlong abbrevo;
@@ -19,7 +19,78 @@
static vlong linesize;
static vlong infoo;
static vlong infosize;
+static vlong frameo;
+static vlong framesize;
+/*
+ * Basic I/O
+ */
+
+static void
+addrput(vlong addr)
+{
+ switch(PtrSize) {
+ case 4:
+ LPUT(addr);
+ break;
+ case 8:
+ VPUT(addr);
+ break;
+ }
+}
+
+
+static int
+uleb128enc(uvlong v, char* dst)
+{
+ uint8 c, len;
+
+ len = 0;
+ do {
+ c = v & 0x7f;
+ v >>= 7;
+ if (v)
+ c |= 0x80;
+ if (dst)
+ *dst++ = c;
+ len++;
+ } while (c & 0x80);
+ return len;
+};
+
+
+static int
+sleb128enc(vlong v, char *dst)
+{
+ uint8 c, s, len;
+
+ len = 0;
+ do {
+ c = v & 0x7f;
+ s = v & 0x40;
+ v >>= 7;
+ if ((v != -1 || !s) && (v != 0 || s))
+ c |= 0x80;
+ if (dst)
+ *dst++ = c;
+ len++;
+ } while(c & 0x80);
+ return len;
+}
+
+static void
+uleb128put(vlong v)
+{
+ char buf[10];
+ strnput(buf, uleb128enc(v, buf));
+}
+
+static void
+sleb128put(vlong v)
+{
+ char buf[10];
+ strnput(buf, sleb128enc(v, buf));
+}
/*
* Defining Abbrevs. This is hardcoded, and there will be
@@ -72,13 +143,34 @@
},
};
+static void
+writeabbrev(void)
+{
+ int i, n;
+
+ abbrevo = cpos();
+ for (i = 1; i < DW_NABRV; i++) {
+ // See section 7.5.3
+ uleb128put(i);
+ uleb128put(abbrevs[i].tag);
+ cput(abbrevs[i].children);
+ // 0 is not a valid attr or form, so we can treat this as
+ // a string
+ n = strlen((char*)abbrevs[i].attr) / 2;
+ strnput((char*)abbrevs[i].attr,
+ (n+1) * sizeof(DWAttrForm));
+ }
+ cput(0);
+ abbrevsize = cpos() - abbrevo;
+}
+
/*
* Debugging Information Entries and their attributes
*/
-
-// for string and block, value contains the length, and data the data,
-// for all others, value is the whole thing and data is null.
+// For DW_CLS_string and _block, value should contain the length, and
+// data the data, for all others, value is the whole thing and data is
+// null.
typedef struct DWAttr DWAttr;
struct DWAttr {
@@ -126,46 +218,6 @@
return a;
}
-static void addrput(vlong addr)
-{
- switch(PtrSize) {
- case 4:
- LPUT(addr);
- break;
- case 8:
- VPUT(addr);
- break;
- }
-}
-
-static void
-uleb128put(uvlong v)
-{
- uint8 c;
-
- do {
- c = v & 0x7f;
- v >>= 7;
- if (v) c |= 0x80;
- cput(c);
- } while (c & 0x80);
-};
-
-static void
-sleb128put(vlong v)
-{
- uint8 c, s;
-
- do {
- c = v & 0x7f;
- s = c & 0x40;
- v >>= 7;
- if ((v != -1 || !s) && (v != 0 || s))
- c |= 0x80;
- cput(c);
- } while(c & 0x80);
-};
-
static void
putattr(int form, int cls, vlong value, char *data)
{
@@ -209,11 +261,11 @@
WPUT(value);
break;
- case DW_FORM_data4: // constant, lineptr, loclistptr, macptr, rangelistptr
+ case DW_FORM_data4: // constant, {line,loclist,mac,rangelist}ptr
LPUT(value);
break;
- case DW_FORM_data8: // constant, lineptr, loclistptr, macptr, rangelistptr
+ case DW_FORM_data8: // constant, {line,loclist,mac,rangelist}ptr
VPUT(value);
break;
@@ -542,28 +594,6 @@
return lh;
}
-static void
-writeabbrev(void)
-{
- int i, n;
-
- abbrevo = cpos();
- for (i = 1; i < DW_NABRV; i++) {
- // See section 7.5.3
- uleb128put(i);
- uleb128put(abbrevs[i].tag);
- cput(abbrevs[i].children);
- // 0 is not a valid attr or form, so we can treat this as
- // a string
- n = strlen((char *) abbrevs[i].attr) / 2;
- strnput((char *) abbrevs[i].attr,
- (n + 1) * sizeof(DWAttrForm));
- }
- cput(0);
- abbrevsize = cpos() - abbrevo;
-}
-
-
static int
guesslang(char *s)
{
@@ -596,8 +626,8 @@
}
if (delta_pc) {
- cput(DW_LNS_advance_pc);
- sleb128put(delta_pc);
+ cput(DW_LNS_advance_pc);
+ sleb128put(delta_pc);
}
cput(DW_LNS_advance_line);
@@ -616,8 +646,8 @@
{
vlong here;
- if (dwinfo != 0 && pc != 0) {
- newattr(dwinfo, DW_AT_high_pc, DW_CLS_ADDRESS, pc, 0);
+ if (dwinfo != nil && pc != 0) {
+ newattr(dwinfo, DW_AT_high_pc, DW_CLS_ADDRESS, pc+1, 0);
}
if (unitstart >= 0) {
@@ -641,19 +671,22 @@
Sym *s;
char *unitname;
vlong unitstart;
- vlong pc, lc, llc, lline;
+ vlong pc, epc, lc, llc, lline;
int currfile;
int i;
Linehist *lh;
+ q = nil;
unitstart = -1;
- pc = 0;
+ epc = pc = 0;
lc = 1;
llc = 1;
currfile = -1;
lineo = cpos();
for (p = textp; p != P; p = p->pcond) {
+ curtext = p; // for diag
+
s = p->from.sym;
if (s == nil || s->type != STEXT) {
diag("->pcond was supposed to loop over STEXT: %P", p);
@@ -663,7 +696,7 @@
// Look for history stack. If we find one,
// we're entering a new compilation unit
if ((unitname = inithist(p->to.autom)) != 0) {
- flushunit(pc, unitstart);
+ flushunit(epc, unitstart);
unitstart = cpos();
if(debug['v'] > 1) {
print("dwarf writelines found %s\n", unitname);
@@ -675,8 +708,8 @@
dwinfo = newdie(dwinfo, DW_ABRV_COMPUNIT);
newattr(dwinfo, DW_AT_name, DW_CLS_STRING, strlen(unitname), unitname);
newattr(dwinfo, DW_AT_language, DW_CLS_CONSTANT, guesslang(unitname), 0);
- newattr(dwinfo, DW_AT_stmt_list, DW_CLS_PTR, unitstart - lineo, 0);
- newattr(dwinfo, DW_AT_low_pc, DW_CLS_ADDRESS, p->pc, 0);
+ newattr(dwinfo, DW_AT_stmt_list, DW_CLS_PTR, unitstart - lineo, 0);
+ newattr(dwinfo, DW_AT_low_pc, DW_CLS_ADDRESS, p->pc, 0);
// Write .debug_line Line Number Program Header (sec 6.2.4)
// Fields marked with (*) must be changed for 64-bit dwarf
LPUT(0); // unit_length (*), will be filled in later.
@@ -701,7 +734,7 @@
// 4 zeros: the string termination + 3 fields.
}
- pc = p->pc;
+ epc = pc = p->pc;
currfile = 1;
lc = 1;
llc = 1;
@@ -711,7 +744,7 @@
cput(DW_LNE_set_address);
addrput(pc);
}
- if (!p->from.sym->reachable)
+ if (!s->reachable)
continue;
if (unitstart < 0) {
diag("reachable code before seeing any history: %P", p);
@@ -721,11 +754,9 @@
dwinfo->child = newdie(dwinfo->child, DW_ABRV_FUNCTION);
newattr(dwinfo->child, DW_AT_name, DW_CLS_STRING, strlen(s->name), s->name);
newattr(dwinfo->child, DW_AT_low_pc, DW_CLS_ADDRESS, p->pc, 0);
- if (debug['v'] > 1)
- print("frame offset: %d\n", p->to.offset);
-// newattr(dwinfo->child, DW_AT_return_addr, DW_CLS_BLOCK, p->to.offset, 0);
for(q = p; q != P && (q == p || q->as != ATEXT); q = q->link) {
+ epc = q->pc;
lh = searchhist(q->line);
if (lh == nil) {
diag("corrupt history or bad absolute line: %P", q);
@@ -734,7 +765,7 @@
lline = lh->line + q->line - lh->absline;
if (debug['v'] > 1)
print("%6llux %s[%lld] %P\n", q->pc, histfile[lh->file], lline, q);
- // Only emit a line program statement if line has changed.
+
if (q->line == lc)
continue;
if (currfile != lh->file) {
@@ -747,13 +778,131 @@
lc = q->line;
llc = lline;
}
- newattr(dwinfo->child, DW_AT_high_pc, DW_CLS_ADDRESS, pc, 0);
+
+ newattr(dwinfo->child, DW_AT_high_pc, DW_CLS_ADDRESS, epc+1, 0);
+
}
- flushunit(pc, unitstart);
+
+ flushunit(epc, unitstart);
linesize = cpos() - lineo;
}
/*
+ * Emit .debug_frame
+ */
+enum
+{
+ CIERESERVE = 16,
+ DATAALIGNMENTFACTOR = -4,
+ FAKERETURNCOLUMN = 16
+};
+
+static void
+putpccfadelta(vlong deltapc, vlong cfa)
+{
+ if (deltapc < 0x40) {
+ cput(DW_CFA_advance_loc + deltapc);
+ } else if (deltapc < 0x100) {
+ cput(DW_CFA_advance_loc1);
+ cput(deltapc);
+ } else if (deltapc < 0x10000) {
+ cput(DW_CFA_advance_loc2);
+ WPUT(deltapc);
+ } else {
+ cput(DW_CFA_advance_loc4);
+ LPUT(deltapc);
+ }
+
+ cput(DW_CFA_def_cfa_offset_sf);
+ sleb128put(cfa / DATAALIGNMENTFACTOR);
+}
+
+static void
+writeframes(void)
+{
+ Prog *p, *q;
+ Sym *s;
+ vlong fdeo, fdesize, pad, cfa, pc, epc;
+
+ frameo = cpos();
+
+ // Emit the CIE, Section 6.4.1
+ LPUT(CIERESERVE); // initial length, must be multiple of PtrSize
+ LPUT(0xffffffff); // cid.
+ cput(3); // dwarf version
+ cput(0); // augmentation ""
+ uleb128put(1); // code_alignment_factor
+ sleb128put(DATAALIGNMENTFACTOR); // guess
+ uleb128put(FAKERETURNCOLUMN); // return_address_register
+
+ cput(DW_CFA_def_cfa);
+ uleb128put(DWARFREGSP); // register SP (**ABI-dependent, defined in l.h)
+ uleb128put(PtrSize); // offset
+
+ cput(DW_CFA_offset + FAKERETURNCOLUMN); // return address
+ uleb128put(-PtrSize / DATAALIGNMENTFACTOR); // at cfa - x*4
+
+ // 4 is to exclude the length field.
+ pad = CIERESERVE + frameo + 4 - cpos();
+ if (pad < 0) {
+ diag("CIERESERVE too small by %lld bytes.", -pad);
+ errorexit();
+ }
+ strnput("", pad);
+
+ for (p = textp; p != P; p = p->pcond) {
+ curtext = p; // for diag
+ s = p->from.sym;
+ if (s == nil || s->type != STEXT) {
+ diag("->pcond was supposed to loop over STEXT: %P", p);
+ continue;
+ }
+ if (!s->reachable)
+ continue;
+
+ fdeo = cpos();
+ // Emit a FDE, Section 6.4.1, starting wit a placeholder.
+ LPUT(0); // length, must be multiple of PtrSize
+ LPUT(0); // Pointer to the CIE above, at offset 0
+ addrput(0); // initial location
+ addrput(0); // address range
+
+ cfa = PtrSize; // CFA starts at sp+PtrSize
+ pc = p->pc;
+ epc = p->pc;
+
+ for(q = p; q != P && (q == p || q->as != ATEXT); q = q->link) {
+ epc = q->pc;
+ if (q->spadj == 0)
+ continue;
+
+ cfa += q->spadj;
+ putpccfadelta(q->pc - pc, cfa);
+ pc = q->pc;
+ }
+
+ fdesize = cpos() - fdeo - 4; // exclude the length field.
+ pad = rnd(fdesize, PtrSize) - fdesize;
+ strnput("", pad);
+ fdesize += pad;
+ cflush();
+
+ // Emit the FDE header for real, Section 6.4.1.
+ seek(cout, fdeo, 0);
+ LPUT(fdesize);
+ LPUT(0);
+ addrput(p->pc);
+ addrput(epc - p->pc);
+
+ cflush();
+ seek(cout, fdeo + 4 + fdesize, 0);
+ }
+
+ cflush();
+ framesize = cpos() - frameo;
+}
+
+/*
* Walk DWarfDebugInfoEntries, and emit .debug_info
*/
static void
@@ -790,8 +939,17 @@
infosize = cpos() - infoo;
}
+void
+dwarfemitdebugsections(void)
+{
+ writeabbrev();
+ writelines();
+ writeframes();
+ writeinfo();
+}
+
/*
- * Elf sections.
+ * Elf.
*/
enum
{
@@ -828,14 +986,6 @@
}
void
-dwarfemitdebugsections(void)
-{
- writeabbrev();
- writelines();
- writeinfo();
-}
-
-void
dwarfaddelfheaders(void)
{
ElfShdr *sh;
@@ -852,6 +1002,12 @@
sh->size = linesize;
sh->addralign = 1;
+ sh = newElfShdr(elfstrdbg[ElfStrDebugFrame]);
+ sh->type = SHT_PROGBITS;
+ sh->off = frameo;
+ sh->size = framesize;
+ sh->addralign = 1;
+
sh = newElfShdr(elfstrdbg[ElfStrDebugInfo]);
sh->type = SHT_PROGBITS;
sh->off = infoo;
@@ -859,6 +1015,9 @@
sh->addralign = 1;
}
+/*
+ * Macho
+ */
void
dwarfaddmachoheaders(void)
{
@@ -873,7 +1032,7 @@
ms = newMachoSeg("__DWARF", 3);
ms->fileoffset = fakestart;
- ms->filesize = abbrevo-fakestart + abbrevsize+linesize+infosize;
+ ms->filesize = abbrevo-fakestart + abbrevsize+linesize+framesize+infosize;
msect = newMachoSect(ms, "__debug_abbrev");
msect->off = abbrevo;
@@ -883,6 +1042,10 @@
msect->off = lineo;
msect->size = linesize;
+ msect = newMachoSect(ms, "__debug_frame");
+ msect->off = frameo;
+ msect->size = framesize;
+
msect = newMachoSect(ms, "__debug_info");
msect->off = infoo;
msect->size = infosize;
diff --git a/src/cmd/ld/dwarf_defs.h b/src/cmd/ld/dwarf_defs.h
index 7bff4fb..3b54f77 100644
--- a/src/cmd/ld/dwarf_defs.h
+++ b/src/cmd/ld/dwarf_defs.h
@@ -452,3 +452,39 @@
DW_MACINFO_end_file = 0x04,
DW_MACINFO_vendor_ext = 0xff,
};
+
+// Table 40.
+enum
+{ // operand,...
+ DW_CFA_nop = 0x00,
+ DW_CFA_set_loc = 0x01, // address
+ DW_CFA_advance_loc1 = 0x02, // 1-byte delta
+ DW_CFA_advance_loc2 = 0x03, // 2-byte delta
+ DW_CFA_advance_loc4 = 0x04, // 4-byte delta
+ DW_CFA_offset_extended = 0x05, // ULEB128 register, ULEB128 offset
+ DW_CFA_restore_extended = 0x06, // ULEB128 register
+ DW_CFA_undefined = 0x07, // ULEB128 register
+ DW_CFA_same_value = 0x08, // ULEB128 register
+ DW_CFA_register = 0x09, // ULEB128 register, ULEB128 register
+ DW_CFA_remember_state = 0x0a,
+ DW_CFA_restore_state = 0x0b,
+ DW_CFA_def_cfa = 0x0c, // ULEB128 register, ULEB128 offset
+ DW_CFA_def_cfa_register = 0x0d, // ULEB128 register
+ DW_CFA_def_cfa_offset = 0x0e, // ULEB128 offset
+ DW_CFA_def_cfa_expression = 0x0f, // BLOCK
+ DW_CFA_expression = 0x10, // ULEB128 register, BLOCK
+ DW_CFA_offset_extended_sf = 0x11, // ULEB128 register, SLEB128 offset
+ DW_CFA_def_cfa_sf = 0x12, // ULEB128 register, SLEB128 offset
+ DW_CFA_def_cfa_offset_sf = 0x13, // SLEB128 offset
+ DW_CFA_val_offset = 0x14, // ULEB128, ULEB128
+ DW_CFA_val_offset_sf = 0x15, // ULEB128, SLEB128
+ DW_CFA_val_expression = 0x16, // ULEB128, BLOCK
+
+ DW_CFA_lo_user = 0x1c,
+ DW_CFA_hi_user = 0x3f,
+
+ // Opcodes that take an addend operand.
+ DW_CFA_advance_loc = 0x1<<6, // +delta
+ DW_CFA_offset = 0x2<<6, // +register (ULEB128 offset)
+ DW_CFA_restore = 0x3<<6, // +register
+};
