[MC/DC][Coverage] Loosen the limit of NumConds from 6 (#82448)

By storing possible test vectors instead of combinations of conditions,
the restriction is dramatically relaxed.

This introduces two options to `cc1`:

* `-fmcdc-max-conditions=32767`
* `-fmcdc-max-test-vectors=2147483646`

This change makes coverage mapping, profraw, and profdata incompatible
with Clang-18.

- Bitmap semantics changed. It is incompatible with previous format.
- `BitmapIdx` in `Decision` points to the end of the bitmap.
- Bitmap is packed per function.
- `llvm-cov` can understand `profdata` generated by `llvm-profdata-18`.

RFC:
https://discourse.llvm.org/t/rfc-coverage-new-algorithm-and-file-format-for-mc-dc/76798

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/unittests/ProfileData/CoverageMappingTest.cpp b/llvm/unittests/ProfileData/CoverageMappingTest.cpp
index f063a33..ef14767 100644
--- a/llvm/unittests/ProfileData/CoverageMappingTest.cpp
+++ b/llvm/unittests/ProfileData/CoverageMappingTest.cpp
@@ -872,7 +872,7 @@ TEST_P(CoverageMappingTest, non_code_region_bitmask) {
   addCMR(Counter::getCounter(2), "file", 1, 1, 5, 5);
   addCMR(Counter::getCounter(3), "file", 1, 1, 5, 5);
 
-  addMCDCDecisionCMR(0, 2, "file", 7, 1, 7, 6);
+  addMCDCDecisionCMR(3, 2, "file", 7, 1, 7, 6);
   addMCDCBranchCMR(Counter::getCounter(0), Counter::getCounter(1), 0, {-1, 1},
                    "file", 7, 2, 7, 3);
   addMCDCBranchCMR(Counter::getCounter(2), Counter::getCounter(3), 1, {-1, -1},
@@ -895,7 +895,7 @@ TEST_P(CoverageMappingTest, decision_before_expansion) {
   addCMR(Counter::getCounter(0), "foo", 3, 23, 5, 2);
 
   // This(4:11) was put after Expansion(4:11) before the fix
-  addMCDCDecisionCMR(0, 2, "foo", 4, 11, 4, 20);
+  addMCDCDecisionCMR(3, 2, "foo", 4, 11, 4, 20);
 
   addExpansionCMR("foo", "A", 4, 11, 4, 12);
   addExpansionCMR("foo", "B", 4, 19, 4, 20);