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work around more commonly-unreachable 6g code sequences.

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R=r
DELTA=23  (23 added, 0 deleted, 0 changed)
OCL=19405
CL=19420
This commit is contained in:
Russ Cox 2008-11-17 17:16:50 -08:00
parent 3f548cd2d9
commit 4d1d5e8a88
1 changed files with 23 additions and 0 deletions
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23
src/cmd/cov/main.c
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@ -160,6 +160,29 @@ missing(uvlong pc, uvlong epc)
return;
}
if(epc - pc == 2 || epc -pc == 3) {
// check for XORL inside shift.
// (on x86 have to implement large shift with explicit zeroing).
// f+90 0x00002c9f CMPL CX,$20
// f+93 0x00002ca2 JCS f+97(SB)
// f+95 0x00002ca4 XORL AX,AX <<<
// f+97 0x00002ca6 SHLL CL,AX
// f+99 0x00002ca8 MOVL $1,CX
//
// f+c8 0x00002cd7 CMPL CX,$40
// f+cb 0x00002cda JCS f+d0(SB)
// f+cd 0x00002cdc XORQ AX,AX <<<
// f+d0 0x00002cdf SHLQ CL,AX
// f+d3 0x00002ce2 MOVQ $1,CX
buf[0] = 0;
machdata->das(text, pc, 0, buf, sizeof buf);
if(strncmp(buf, "XOR", 3) == 0) {
machdata->das(text, epc, 0, buf, sizeof buf);
if(strncmp(buf, "SHL", 3) == 0 || strncmp(buf, "SHR", 3) == 0)
return;
}
}
// show first instruction to make clear where we were.
machdata->das(text, pc, 0, buf, sizeof buf);