libgo: fix for unaligned read in go-unwind.c's read_encoded_value()

Change code to work properly reading unaligned data on architectures
    that don't support unaliged reads. This fixes a regression (broke
    Solaris/sparc) introduced in https://golang.org/cl/90235.
    
    Reviewed-on: https://go-review.googlesource.com/111296

From-SVN: r259935
This commit is contained in:
Ian Lance Taylor 2018-05-04 14:29:05 +00:00
parent 71d372eba9
commit 772455c964
2 changed files with 44 additions and 12 deletions

View File

@ -1,4 +1,4 @@
30e2033a91fc08be9351d26737599a1fa6486017
0c9b7a1ca4c6308345ea2a276cf820ff52513592
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.

View File

@ -197,10 +197,6 @@ read_sleb128 (const uint8_t *p, _sleb128_t *val)
#define ROUND_UP_TO_PVB(x) (x + sizeof(void *) - 1) &- sizeof(void *)
#define COPY_AND_ADVANCE(dst, ptr, typ) \
(dst = *((const typ*)ptr), \
ptr += sizeof(typ))
static inline const uint8_t *
read_encoded_value (struct _Unwind_Context *context, uint8_t encoding,
const uint8_t *p, _Unwind_Ptr *val)
@ -221,17 +217,53 @@ read_encoded_value (struct _Unwind_Context *context, uint8_t encoding,
switch (encoding & 0x0f)
{
case DW_EH_PE_sdata2:
{
int16_t result;
__builtin_memcpy (&result, p, sizeof(int16_t));
decoded = result;
p += sizeof(int16_t);
break;
}
case DW_EH_PE_udata2:
COPY_AND_ADVANCE (decoded, p, uint16_t);
break;
{
uint16_t result;
__builtin_memcpy (&result, p, sizeof(uint16_t));
decoded = result;
p += sizeof(uint16_t);
break;
}
case DW_EH_PE_sdata4:
{
int32_t result;
__builtin_memcpy (&result, p, sizeof(int32_t));
decoded = result;
p += sizeof(int32_t);
break;
}
case DW_EH_PE_udata4:
COPY_AND_ADVANCE (decoded, p, uint32_t);
break;
{
uint32_t result;
__builtin_memcpy (&result, p, sizeof(uint32_t));
decoded = result;
p += sizeof(uint32_t);
break;
}
case DW_EH_PE_sdata8:
{
int64_t result;
__builtin_memcpy (&result, p, sizeof(int64_t));
decoded = result;
p += sizeof(int64_t);
break;
}
case DW_EH_PE_udata8:
COPY_AND_ADVANCE (decoded, p, uint64_t);
break;
{
uint64_t result;
__builtin_memcpy (&result, p, sizeof(uint64_t));
decoded = result;
p += sizeof(uint64_t);
break;
}
case DW_EH_PE_uleb128:
{
_uleb128_t value;
@ -247,7 +279,7 @@ read_encoded_value (struct _Unwind_Context *context, uint8_t encoding,
break;
}
case DW_EH_PE_absptr:
decoded = (_Unwind_Internal_Ptr)(*(const void *const *)p);
__builtin_memcpy (&decoded, (const void *)p, sizeof(const void*));
p += sizeof(void *);
break;
default: