]> git.ipfire.org Git - thirdparty/binutils-gdb.git/commitdiff
gas: add .cv_ucomp and .cv_scomp pseudo-directives
authorMark Harmstone <mark@harmstone.com>
Sat, 2 Nov 2024 22:05:06 +0000 (22:05 +0000)
committerMark Harmstone <mark@harmstone.com>
Wed, 13 Nov 2024 03:11:35 +0000 (03:11 +0000)
Add .cv_ucomp and .cv_scomp pseudo-directives for object files for
Windows targets, which encode compressed CodeView integers according to
the algorithm in CVCompressData in
https://github.com/Microsoft/microsoft-pdb/blob/master/include/cvinfo.h.
This is essentially Microsoft's answer to the LEB128, though used in far
fewer places.

CodeView uses these to encode the "binary annotations" in the
S_INLINESITE symbol, which express the relationship between code offsets
and line numbers in inlined functions. This has to be done in the
assembler as GCC doesn't know how many bytes each instruction takes up.
There's no equivalent for this for MSVC or LLVM, as in both cases the
assembler and compiler are integrated.

.cv_ucomp represents an unsigned big-endian integer between 0 and 0x1fffffff,
taking up 1, 2, or 4 bytes:

Value between 0 and 0x7f:

0aaaaaaa -> 0aaaaaaa (identity-mapped)

Value between 0x80 and 0x3fff:

00aaaaaa bbbbbbbb -> 10aaaaaa bbbbbbbb

Value between 0x4000 and 0x1fffffff:
000aaaaa bbbbbbbb ccccccccc dddddddd ->
110aaaaa bbbbbbbb ccccccccc dddddddd

.cv_scomp represents a signed big-endian integer between -0xfffffff and
0xfffffff, encoded according to EncodeSignedInt32 in cvinfo.h. The
absolute value of the integer is shifted left one bit, the LSB set
for a negative value, and the result expressed as if it were a
.cv_ucomp: cv_scomp(x) = cv_ucomp((abs(x) << 1) | (x < 0 ? 1 : 0))

gas/as.h
gas/codeview.c
gas/codeview.h
gas/read.c
gas/testsuite/gas/pe/cv_comp.d [new file with mode: 0644]
gas/testsuite/gas/pe/cv_comp.s [new file with mode: 0644]
gas/testsuite/gas/pe/pe.exp
gas/write.c

index 780773cd78cb583aa77dcf4490bc170f0bf2ea5e..3d5f710c5c5e9d71c440356430b1f51ed2f6f464 100644 (file)
--- a/gas/as.h
+++ b/gas/as.h
@@ -263,7 +263,10 @@ enum _relax_state
   rs_dwarf2dbg,
 
   /* SFrame FRE type selection optimization.  */
-  rs_sframe
+  rs_sframe,
+
+  /* CodeView compressed integer.  */
+  rs_cv_comp,
 };
 
 typedef enum _relax_state relax_stateT;
index 3eaa7a64fd2dc70c9be983941744a685b788a1d2..309f3b6920278fea9ad52d50a56eac2df37f99e0 100644 (file)
@@ -533,6 +533,90 @@ codeview_generate_asm_lineno (void)
   lf->num_lines++;
 }
 
+/* Output a compressed CodeView integer.  The return value is the number of
+   bytes used.  */
+
+unsigned int
+output_cv_comp (char *p, offsetT value, int sign)
+{
+  char *orig = p;
+
+  if (sign)
+    {
+      if (value < -0xfffffff || value > 0xfffffff)
+       {
+         as_bad (_("value cannot be expressed as a .cv_scomp"));
+         return 0;
+       }
+    }
+  else
+    {
+      if (value < 0 || value > 0x1fffffff)
+       {
+         as_bad (_("value cannot be expressed as a .cv_ucomp"));
+         return 0;
+       }
+    }
+
+  if (sign)
+    {
+      if (value >= 0)
+       value <<= 1;
+      else
+       value = (-value << 1) | 1;
+    }
+
+  if (value <= 0x7f)
+    {
+      *p++ = value;
+    }
+  else if (value <= 0x3fff)
+    {
+      *p++ = 0x80 | (value >> 8);
+      *p++ = value & 0xff;
+    }
+  else
+    {
+      *p++ = 0xc0 | (value >> 24);
+      *p++ = (value >> 16) & 0xff;
+      *p++ = (value >> 8) & 0xff;
+      *p++ = value & 0xff;
+    }
+
+  return p - orig;
+}
+
+/* Return the size needed to output a compressed CodeView integer.  */
+
+unsigned int
+sizeof_cv_comp (offsetT value, int sign)
+{
+  if (sign)
+    {
+      if (value < -0xfffffff || value > 0xfffffff)
+       return 0;
+
+      if (value >= 0)
+       value <<= 1;
+      else
+       value = (-value << 1) | 1;
+    }
+  else
+    {
+      if (value > 0x1fffffff)
+       return 0;
+    }
+
+  if (value <= 0x7f)
+    return 1;
+  else if (value <= 0x3fff)
+    return 2;
+  else if (value <= 0x1fffffff)
+    return 4;
+  else
+    return 0;
+}
+
 #else
 
 void
index 57f8dfaedbf3ccd426827f856113c54cd3f8f6a6..ef2e78a94771c4464f51a1aa3fb1140e294e59f9 100644 (file)
@@ -101,5 +101,7 @@ struct cv_line
 
 extern void codeview_finish (void);
 extern void codeview_generate_asm_lineno (void);
+extern unsigned int output_cv_comp (char *, offsetT, int);
+extern unsigned int sizeof_cv_comp (offsetT, int);
 
 #endif
index aefbd7aefe8912e03c85a707ec296347154703e3..589c7b080c228fe27bd09bbffb2ced0280c3061e 100644 (file)
@@ -265,6 +265,9 @@ static void poend (void);
 static size_t get_macro_line_sb (sb *);
 static void generate_file_debug (void);
 static char *_find_end_of_line (char *, int, int, int);
+#if defined (TE_PE) && defined (O_secrel)
+static void s_cv_comp (int sign);
+#endif
 \f
 void
 read_begin (void)
@@ -369,6 +372,10 @@ static const pseudo_typeS potable[] = {
   {"comm", s_comm, 0},
   {"common", s_mri_common, 0},
   {"common.s", s_mri_common, 1},
+#if defined (TE_PE) && defined (O_secrel)
+  {"cv_scomp", s_cv_comp, 1},
+  {"cv_ucomp", s_cv_comp, 0},
+#endif
   {"data", s_data, 0},
   {"dc", cons, 2},
   {"dc.a", cons, 0},
@@ -5457,6 +5464,97 @@ s_leb128 (int sign)
   demand_empty_rest_of_line ();
 }
 \f
+#if defined (TE_PE) && defined (O_secrel)
+
+/* Generate the appropriate fragments for a given expression to emit a
+   cv_comp value.  SIGN is 1 for cv_scomp, 0 for cv_ucomp.  */
+
+static void
+emit_cv_comp_expr (expressionS *exp, int sign)
+{
+  operatorT op = exp->X_op;
+
+  if (op == O_absent || op == O_illegal)
+    {
+      as_warn (_("zero assumed for missing expression"));
+      exp->X_add_number = 0;
+      op = O_constant;
+    }
+  else if (op == O_big)
+    {
+      as_bad (_("number invalid"));
+      exp->X_add_number = 0;
+      op = O_constant;
+    }
+  else if (op == O_register)
+    {
+      as_warn (_("register value used as expression"));
+      op = O_constant;
+    }
+
+  if (now_seg == absolute_section)
+    {
+      if (op != O_constant || exp->X_add_number != 0)
+       as_bad (_("attempt to store value in absolute section"));
+      abs_section_offset++;
+      return;
+    }
+
+  if ((op != O_constant || exp->X_add_number != 0) && in_bss ())
+    as_bad (_("attempt to store non-zero value in section `%s'"),
+           segment_name (now_seg));
+
+  /* Let the backend know that subsequent data may be byte aligned.  */
+#ifdef md_cons_align
+  md_cons_align (1);
+#endif
+
+  if (op == O_constant)
+    {
+      offsetT value = exp->X_add_number;
+      unsigned int size;
+      char *p;
+
+      /* If we've got a constant, emit the thing directly right now.  */
+
+      size = sizeof_cv_comp (value, sign);
+      p = frag_more (size);
+      if (output_cv_comp (p, value, sign) > size)
+       abort ();
+    }
+  else
+    {
+      /* Otherwise, we have to create a variable sized fragment and
+        resolve things later.  */
+
+      frag_var (rs_cv_comp, 4, 0, sign, make_expr_symbol (exp), 0, NULL);
+    }
+}
+
+/* Parse the .cv_ucomp and .cv_scomp pseudos.  */
+
+static void
+s_cv_comp (int sign)
+{
+  expressionS exp;
+
+#ifdef md_flush_pending_output
+  md_flush_pending_output ();
+#endif
+
+  do
+    {
+      expression (&exp);
+      emit_cv_comp_expr (&exp, sign);
+    }
+  while (*input_line_pointer++ == ',');
+
+  input_line_pointer--;
+  demand_empty_rest_of_line ();
+}
+
+#endif /* TE_PE && O_secrel */
+
 /* Code for handling base64 encoded strings.
    Based upon code in sharutils' lib/base64.c source file, written by
    Simon Josefsson.  Which was partially adapted from GNU MailUtils
diff --git a/gas/testsuite/gas/pe/cv_comp.d b/gas/testsuite/gas/pe/cv_comp.d
new file mode 100644 (file)
index 0000000..3a87554
--- /dev/null
@@ -0,0 +1,14 @@
+#objdump: -s -j .rdata
+#name: CodeView compressed integer test
+
+.*: .*
+
+Contents of section .rdata:
+ 0000 21002101 212a217f 21808021 853921bf  .*
+ 0010 ff21c000 400021c0 0f424021 dfffffff  .*
+ 0020 21002102 21542180 fe218100 218a7221  .*
+ 0030 c0007ffe 21c00080 0021c01e 848021df  .*
+ 0040 fffffe21 03215521 80ff2181 01218a73  .*
+ 0050 21c0007f ff21c000 800121c0 1e848121  .*
+ 0060 dfffffff 21022104 21900421 04210821  .*
+ 0070 a0082105 210921a0 0921.*
diff --git a/gas/testsuite/gas/pe/cv_comp.s b/gas/testsuite/gas/pe/cv_comp.s
new file mode 100644 (file)
index 0000000..29183d5
--- /dev/null
@@ -0,0 +1,105 @@
+       .section .rdata
+
+       .ascii          "!"
+       .cv_ucomp       0
+       .ascii          "!"
+       .cv_ucomp       1
+       .ascii          "!"
+       .cv_ucomp       42
+       .ascii          "!"
+       .cv_ucomp       127
+       .ascii          "!"
+       .cv_ucomp       128
+       .ascii          "!"
+       .cv_ucomp       1337
+       .ascii          "!"
+       .cv_ucomp       16383
+       .ascii          "!"
+       .cv_ucomp       16384
+       .ascii          "!"
+       .cv_ucomp       1000000
+       .ascii          "!"
+       .cv_ucomp       536870911
+
+       .ascii          "!"
+       .cv_scomp       0
+       .ascii          "!"
+       .cv_scomp       1
+       .ascii          "!"
+       .cv_scomp       42
+       .ascii          "!"
+       .cv_scomp       127
+       .ascii          "!"
+       .cv_scomp       128
+       .ascii          "!"
+       .cv_scomp       1337
+       .ascii          "!"
+       .cv_scomp       16383
+       .ascii          "!"
+       .cv_scomp       16384
+       .ascii          "!"
+       .cv_scomp       1000000
+       .ascii          "!"
+       .cv_scomp       268435455
+
+       .ascii          "!"
+       .cv_scomp       -1
+       .ascii          "!"
+       .cv_scomp       -42
+       .ascii          "!"
+       .cv_scomp       -127
+       .ascii          "!"
+       .cv_scomp       -128
+       .ascii          "!"
+       .cv_scomp       -1337
+       .ascii          "!"
+       .cv_scomp       -16383
+       .ascii          "!"
+       .cv_scomp       -16384
+       .ascii          "!"
+       .cv_scomp       -1000000
+       .ascii          "!"
+       .cv_scomp       -268435455
+
+       .ascii          "!"
+       # 2
+       .cv_ucomp       addr2 - addr1
+       .ascii          "!"
+       # 4
+       .cv_ucomp       addr3 - addr1
+       .ascii          "!"
+       # 4100
+       .cv_ucomp       addr4 - addr1
+
+       .ascii          "!"
+       # 2
+       .cv_scomp       addr2 - addr1
+       .ascii          "!"
+       # 4
+       .cv_scomp       addr3 - addr1
+       .ascii          "!"
+       # 4100
+       .cv_scomp       addr4 - addr1
+       .ascii          "!"
+       # -2
+       .cv_scomp       addr1 - addr2
+       .ascii          "!"
+       # -4
+       .cv_scomp       addr1 - addr3
+       .ascii          "!"
+       # -4100
+       .cv_scomp       addr1 - addr4
+       .ascii          "!"
+
+       .data
+       .space          1
+addr1: # .data + 0x1
+       .space          2
+addr2: # .data + 0x3
+       .space          2
+       # force new fragment
+       .text
+       .data
+addr3: # .data + 0x5
+       .space          0x1000
+addr4: # .data + 0x1005
index 5f8396e59244ee1ace5dce480ec68b0150a833a5..f9cbc07e8993c1f4b0d1a625000ac21099403e35 100644 (file)
@@ -38,6 +38,11 @@ run_dump_test "section-exclude"
 
 run_dump_test "set"
 
+if { [istarget "aarch64-*-*"] || [istarget "arm*-*-*"] || [istarget "i*86-*-*"]
+    || [istarget "x86_64-*-*"] } then {
+  run_dump_test "cv_comp"
+}
+
 # SEH related tests
 
 # These tests are only for x86_64 targets
index 853a9a012b765661bfbea470dd33fa2cda206c10..a9c53d70f7f959e3cec31e52ecdda855cf5e6250 100644 (file)
@@ -26,6 +26,7 @@
 #include "output-file.h"
 #include "dwarf2dbg.h"
 #include "compress-debug.h"
+#include "codeview.h"
 
 #ifndef TC_FORCE_RELOCATION
 #define TC_FORCE_RELOCATION(FIX)               \
@@ -513,6 +514,32 @@ cvt_frag_to_fill (segT sec ATTRIBUTE_UNUSED, fragS *fragP)
       break;
 #endif
 
+#if defined (TE_PE) && defined (O_secrel)
+    case rs_cv_comp:
+      {
+       offsetT value = S_GET_VALUE (fragP->fr_symbol);
+       int size;
+
+       if (!S_IS_DEFINED (fragP->fr_symbol))
+         {
+           as_bad_where (fragP->fr_file, fragP->fr_line,
+                         _(".cv_%ccomp operand is an undefined symbol: %s"),
+                         fragP->fr_subtype ? 's' : 'u',
+                         S_GET_NAME (fragP->fr_symbol));
+         }
+
+       size = output_cv_comp (fragP->fr_literal + fragP->fr_fix, value,
+                              fragP->fr_subtype);
+
+       fragP->fr_fix += size;
+       fragP->fr_type = rs_fill;
+       fragP->fr_var = 0;
+       fragP->fr_offset = 0;
+       fragP->fr_symbol = NULL;
+      }
+      break;
+#endif
+
     default:
       BAD_CASE (fragP->fr_type);
       break;
@@ -2767,6 +2794,9 @@ relax_segment (struct frag *segment_frag_root, segT segment, int pass)
 #endif
 
        case rs_leb128:
+#if defined (TE_PE) && defined (O_secrel)
+       case rs_cv_comp:
+#endif
          /* Initial guess is always 1; doing otherwise can result in
             stable solutions that are larger than the minimum.  */
          address += fragP->fr_offset = 1;
@@ -3120,6 +3150,20 @@ relax_segment (struct frag *segment_frag_root, segT segment, int pass)
                }
                break;
 
+#if defined (TE_PE) && defined (O_secrel)
+             case rs_cv_comp:
+               {
+                 valueT value;
+                 offsetT size;
+
+                 value = resolve_symbol_value (fragP->fr_symbol);
+                 size = sizeof_cv_comp (value, fragP->fr_subtype);
+                 growth = size - fragP->fr_offset;
+                 fragP->fr_offset = size;
+               }
+             break;
+#endif
+
              case rs_cfa:
                growth = eh_frame_relax_frag (fragP);
                break;