Reland "[InstrProf][compiler-rt] Enable MC/DC Support in LLVM Source-based Code Coverage (1/3)"

Part 1 of 3. This includes the LLVM back-end processing and profile
reading/writing components. compiler-rt changes are included.

Differential Revision: https://reviews.llvm.org/D138846

1 files changed, 138 insertions, 0 deletions

diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index 3631dff..803503a 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -13954,6 +13954,144 @@ pass will generate the appropriate data structures and replace the
 ``llvm.instrprof.value.profile`` intrinsic with the call to the profile
 runtime library with proper arguments.
 
+'``llvm.instrprof.mcdc.parameters``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare void @llvm.instrprof.mcdc.parameters(ptr <name>, i64 <hash>,
+                                                   i32 <bitmap-bytes>)
+
+Overview:
+"""""""""
+
+The '``llvm.instrprof.mcdc.parameters``' intrinsic is used to initiate MC/DC
+code coverage instrumentation for a function.
+
+Arguments:
+""""""""""
+
+The first argument is a pointer to a global variable containing the
+name of the entity being instrumented. This should generally be the
+(mangled) function name for a set of counters.
+
+The second argument is a hash value that can be used by the consumer
+of the profile data to detect changes to the instrumented source.
+
+The third argument is the number of bitmap bytes required by the function to
+record the number of test vectors executed for each boolean expression.
+
+Semantics:
+""""""""""
+
+This intrinsic represents basic MC/DC parameters initiating one or more MC/DC
+instrumentation sequences in a function. It will cause the ``-instrprof`` pass
+to generate the appropriate data structures and the code to instrument MC/DC
+test vectors in a format that can be written out by a compiler runtime and
+consumed via the ``llvm-profdata`` tool.
+
+'``llvm.instrprof.mcdc.condbitmap.update``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare void @llvm.instrprof.mcdc.condbitmap.update(ptr <name>, i64 <hash>,
+                                                          i32 <condition-id>,
+                                                          ptr <mcdc-temp-addr>,
+                                                          i1 <bool-value>)
+
+Overview:
+"""""""""
+
+The '``llvm.instrprof.mcdc.condbitmap.update``' intrinsic is used to track
+MC/DC condition evaluation for each condition in a boolean expression.
+
+Arguments:
+""""""""""
+
+The first argument is a pointer to a global variable containing the
+name of the entity being instrumented. This should generally be the
+(mangled) function name for a set of counters.
+
+The second argument is a hash value that can be used by the consumer
+of the profile data to detect changes to the instrumented source.
+
+The third argument is an ID of a condition to track. This value is used as a
+bit index into the condition bitmap.
+
+The fourth argument is the address of the condition bitmap.
+
+The fifth argument is the boolean value representing the evaluation of the
+condition (true or false)
+
+Semantics:
+""""""""""
+
+This intrinsic represents the update of a condition bitmap that is local to a
+function and will cause the ``-instrprof`` pass to generate the code to
+instrument the control flow around each condition in a boolean expression. The
+ID of each condition corresponds to a bit index in the condition bitmap which
+is set based on the evaluation of the condition.
+
+'``llvm.instrprof.mcdc.tvbitmap.update``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare void @llvm.instrprof.mcdc.tvbitmap.update(ptr <name>, i64 <hash>,
+                                                        i32 <bitmap-bytes>)
+                                                        i32 <bitmap-index>,
+                                                        ptr <mcdc-temp-addr>)
+
+Overview:
+"""""""""
+
+The '``llvm.instrprof.mcdc.tvbitmap.update``' intrinsic is used to track MC/DC
+test vector execution after each boolean expression has been fully executed.
+The overall value of the condition bitmap, after it has been successively
+updated using the '``llvm.instrprof.mcdc.condbitmap.update``' intrinsic with
+the true or false evaluation of each condition, uniquely identifies an executed
+MC/DC test vector and is used as a bit index into the global test vector
+bitmap.
+
+Arguments:
+""""""""""
+
+The first argument is a pointer to a global variable containing the
+name of the entity being instrumented. This should generally be the
+(mangled) function name for a set of counters.
+
+The second argument is a hash value that can be used by the consumer
+of the profile data to detect changes to the instrumented source.
+
+The third argument is the number of bitmap bytes required by the function to
+record the number of test vectors executed for each boolean expression.
+
+The fourth argument is the byte index into the global test vector bitmap
+corresponding to the function.
+
+The fifth argument is the address of the condition bitmap, which contains a
+value representing an executed MC/DC test vector. It is loaded and used as the
+bit index of the test vector bitmap.
+
+Semantics:
+""""""""""
+
+This intrinsic represents the final operation of an MC/DC instrumentation
+sequence and will cause the ``-instrprof`` pass to generate the code to
+instrument an update of a function's global test vector bitmap to indicate that
+a test vector has been executed. The global test vector bitmap can be consumed
+by the ``llvm-profdata`` and ``llvm-cov`` tools.
+
 '``llvm.thread.pointer``' Intrinsic
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^