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| author | Than McIntosh <thanm@google.com> | 2022-04-19 19:41:40 -0400 |
|---|---|---|
| committer | Than McIntosh <thanm@google.com> | 2022-09-27 10:29:51 +0000 |
| commit | 072c7d4969862c84430cc2daef20a8f7f3ba78a2 (patch) | |
| tree | f0cb83f688a4a5bc18168f1e1e2a72f37999a783 /src/cmd/link/internal/ld/data.go | |
| parent | 361f5eba9f9e9902226e7edac76646253b7025e4 (diff) | |
| download | go-072c7d4969862c84430cc2daef20a8f7f3ba78a2.tar.xz | |
cmd/compile,cmd/link: hooks for identifying coverage counters
Add a new "coverage counter" classification for variables to be used
for storing code coverage counter values (somewhat in the same way
that we identify fuzzer counters). Tagging such variables allows us to
aggregate them in the linker, and to treat updates specially.
Updates #51430.
Change-Id: Ib49fb05736ffece98bcc2f7a7c37e991b7f67bbb
Reviewed-on: https://go-review.googlesource.com/c/go/+/401235
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Diffstat (limited to 'src/cmd/link/internal/ld/data.go')
| -rw-r--r-- | src/cmd/link/internal/ld/data.go | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go index c2668b29a4..c23eac08a4 100644 --- a/src/cmd/link/internal/ld/data.go +++ b/src/cmd/link/internal/ld/data.go @@ -1074,6 +1074,8 @@ func dwarfblk(ctxt *Link, out *OutBuf, addr int64, size int64) { writeBlocks(ctxt, out, ctxt.outSem, ctxt.loader, syms, addr, size, zeros[:]) } +var covCounterDataStartOff, covCounterDataLen uint64 + var zeros [512]byte var ( @@ -1781,6 +1783,15 @@ func (state *dodataState) allocateDataSections(ctxt *Link) { ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.enoptrbss", 0), sect) ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.end", 0), sect) + // Code coverage counters are assigned to the .noptrbss section. + // We assign them in a separate pass so that they stay aggregated + // together in a single blob (coverage runtime depends on this). + covCounterDataStartOff = sect.Length + state.assignToSection(sect, sym.SCOVERAGE_COUNTER, sym.SNOPTRBSS) + covCounterDataLen = sect.Length - covCounterDataStartOff + ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.covctrs", 0), sect) + ldr.SetSymSect(ldr.LookupOrCreateSym("runtime.ecovctrs", 0), sect) + // Coverage instrumentation counters for libfuzzer. if len(state.data[sym.SLIBFUZZER_8BIT_COUNTER]) > 0 { sect := state.allocateNamedSectionAndAssignSyms(&Segdata, "__sancov_cntrs", sym.SLIBFUZZER_8BIT_COUNTER, sym.Sxxx, 06) @@ -2682,6 +2693,8 @@ func (ctxt *Link) address() []*sym.Segment { ctxt.xdefine("runtime.edata", sym.SDATA, int64(data.Vaddr+data.Length)) ctxt.xdefine("runtime.noptrbss", sym.SNOPTRBSS, int64(noptrbss.Vaddr)) ctxt.xdefine("runtime.enoptrbss", sym.SNOPTRBSS, int64(noptrbss.Vaddr+noptrbss.Length)) + ctxt.xdefine("runtime.covctrs", sym.SCOVERAGE_COUNTER, int64(noptrbss.Vaddr+covCounterDataStartOff)) + ctxt.xdefine("runtime.ecovctrs", sym.SCOVERAGE_COUNTER, int64(noptrbss.Vaddr+covCounterDataStartOff+covCounterDataLen)) ctxt.xdefine("runtime.end", sym.SBSS, int64(Segdata.Vaddr+Segdata.Length)) if fuzzCounters != nil { |