Add support for -fcoverage-mapping support (#24160)

Main introduction is porting `llvm-project/compiler_rt/lib/profile`
`into system/lib/compiler_rt/lib/profile`

Related
#13072
llvm/llvm-project#111332

No modifications were required for what was ported. llvm-cov worked fine
for me with simple project.

* `-g` is required to produce a properly instrumented binary `error:
failed to load coverage: 'my.wasm': no coverage data found`

Author: arsnyder16

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 4.0.11 (in development)
 -----------------------
+- Add support for [Source-based Code Coverage](https://clang.llvm.org/docs/SourceBasedCodeCoverage.html)
+  To build with coverage enabled use `-fprofile-instr-generate -fcoverage-mapping`. (#24160)
 - The `ENVIRONMENT` setting will now be automatically updated to include
   `worker` if multi-threading is enabled. (#24525)
 - Removed the `HEADLESS` option. It tried to simulate a minimal browser-like

system/lib/compiler-rt/include/profile/InstrProfData.inc

@@ -0,0 +1,55 @@
+/*===-- MemEntryDef.inc - MemProf profiling runtime macros -*- C++ -*-======== *\
+|*
+|* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+|* See https://llvm.org/LICENSE.txt for license information.
+|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+|*
+\*===----------------------------------------------------------------------===*/
+/*
+ * This file defines the macros for memprof profiling data structures.
+ * Eg. usage to define the memprof meminfoblock struct:
+ *
+ * struct MemInfoBlock {
+ * #define MIBEntryDef(NameTag, Name, Type) Type Name;
+ * #include MIBEntryDef.inc
+ * #undef MIBEntryDef
+ * };
+ *
+ * This file has two identical copies. The primary copy lives in LLVM and
+ * the other one sits in compiler-rt/include/profile directory. To make changes
+ * in this file, first modify the primary copy and copy it over to compiler-rt.
+ * Testing of any change in this file can start only after the two copies are
+ * synced up.
+ *
+\*===----------------------------------------------------------------------===*/
+#ifndef MIBEntryDef
+#define MIBEntryDef(NameTag, Name, Type)
+#endif
+
+MIBEntryDef(AllocCount = 1, AllocCount, uint32_t)
+MIBEntryDef(TotalAccessCount = 2, TotalAccessCount, uint64_t)
+MIBEntryDef(MinAccessCount = 3, MinAccessCount, uint64_t)
+MIBEntryDef(MaxAccessCount = 4, MaxAccessCount, uint64_t)
+MIBEntryDef(TotalSize = 5, TotalSize, uint64_t)
+MIBEntryDef(MinSize = 6, MinSize, uint32_t)
+MIBEntryDef(MaxSize = 7, MaxSize, uint32_t)
+MIBEntryDef(AllocTimestamp = 8, AllocTimestamp, uint32_t)
+MIBEntryDef(DeallocTimestamp = 9, DeallocTimestamp, uint32_t)
+MIBEntryDef(TotalLifetime = 10, TotalLifetime, uint64_t)
+MIBEntryDef(MinLifetime = 11, MinLifetime, uint32_t)
+MIBEntryDef(MaxLifetime = 12, MaxLifetime, uint32_t)
+MIBEntryDef(AllocCpuId = 13, AllocCpuId, uint32_t)
+MIBEntryDef(DeallocCpuId = 14, DeallocCpuId, uint32_t)
+MIBEntryDef(NumMigratedCpu = 15, NumMigratedCpu, uint32_t)
+MIBEntryDef(NumLifetimeOverlaps = 16, NumLifetimeOverlaps, uint32_t)
+MIBEntryDef(NumSameAllocCpu = 17, NumSameAllocCpu, uint32_t)
+MIBEntryDef(NumSameDeallocCpu = 18, NumSameDeallocCpu, uint32_t)
+MIBEntryDef(DataTypeId = 19, DataTypeId, uint64_t)
+MIBEntryDef(TotalAccessDensity = 20, TotalAccessDensity, uint64_t)
+MIBEntryDef(MinAccessDensity = 21, MinAccessDensity, uint32_t)
+MIBEntryDef(MaxAccessDensity = 22, MaxAccessDensity, uint32_t)
+MIBEntryDef(TotalLifetimeAccessDensity = 23, TotalLifetimeAccessDensity, uint64_t)
+MIBEntryDef(MinLifetimeAccessDensity = 24, MinLifetimeAccessDensity, uint32_t)
+MIBEntryDef(MaxLifetimeAccessDensity = 25, MaxLifetimeAccessDensity, uint32_t)
+MIBEntryDef(AccessHistogramSize = 26, AccessHistogramSize, uint32_t)
+MIBEntryDef(AccessHistogram = 27, AccessHistogram, uintptr_t)

system/lib/compiler-rt/include/profile/MIBEntryDef.inc

@@ -0,0 +1,235 @@
+#ifndef MEMPROF_DATA_INC
+#define MEMPROF_DATA_INC
+/*===-- MemProfData.inc - MemProf profiling runtime structures -*- C++ -*-=== *\
+|*
+|* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+|* See https://llvm.org/LICENSE.txt for license information.
+|* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+|*
+\*===----------------------------------------------------------------------===*/
+/*
+ * This is the main file that defines all the data structure, signature,
+ * constant literals that are shared across profiling runtime library,
+ * and host tools (reader/writer).
+ *
+ * This file has two identical copies. The primary copy lives in LLVM and
+ * the other one sits in compiler-rt/include/profile directory. To make changes
+ * in this file, first modify the primary copy and copy it over to compiler-rt.
+ * Testing of any change in this file can start only after the two copies are
+ * synced up.
+ *
+\*===----------------------------------------------------------------------===*/
+#include <string.h>
+
+#ifdef _MSC_VER
+#define PACKED(...) __pragma(pack(push,1)) __VA_ARGS__ __pragma(pack(pop))
+#else
+#define PACKED(...) __VA_ARGS__ __attribute__((__packed__))
+#endif
+
+// A 64-bit magic number to uniquely identify the raw binary memprof profile file.
+#define MEMPROF_RAW_MAGIC_64                                                                        \
+  ((uint64_t)255 << 56 | (uint64_t)'m' << 48 | (uint64_t)'p' << 40 | (uint64_t)'r' << 32 |          \
+   (uint64_t)'o' << 24 | (uint64_t)'f' << 16 | (uint64_t)'r' << 8 | (uint64_t)129)
+
+// The version number of the raw binary format.
+#define MEMPROF_RAW_VERSION 4ULL
+
+// Currently supported versions.
+#define MEMPROF_RAW_SUPPORTED_VERSIONS                                         \
+  { 3ULL, 4ULL }
+
+#define MEMPROF_V3_MIB_SIZE 132ULL;
+
+#define MEMPROF_BUILDID_MAX_SIZE 32ULL
+
+namespace llvm {
+namespace memprof {
+// A struct describing the header used for the raw binary memprof profile format.
+PACKED(struct Header {
+  uint64_t Magic;
+  uint64_t Version;
+  uint64_t TotalSize;
+  uint64_t SegmentOffset;
+  uint64_t MIBOffset;
+  uint64_t StackOffset;
+});
+
+// A struct describing the information necessary to describe a /proc/maps
+// segment entry for a particular binary/library identified by its build id.
+PACKED(struct SegmentEntry {
+  uint64_t Start;
+  uint64_t End;
+  uint64_t Offset;
+  uint64_t BuildIdSize;
+  uint8_t BuildId[MEMPROF_BUILDID_MAX_SIZE] = {0};
+
+  // This constructor is only used in tests so don't set the BuildId.
+  SegmentEntry(uint64_t S, uint64_t E, uint64_t O)
+      : Start(S), End(E), Offset(O), BuildIdSize(0) {}
+
+  SegmentEntry(const SegmentEntry& S) {
+    Start = S.Start;
+    End = S.End;
+    Offset = S.Offset;
+    BuildIdSize = S.BuildIdSize;
+    memcpy(BuildId, S.BuildId, S.BuildIdSize);
+  }
+
+  SegmentEntry& operator=(const SegmentEntry& S) {
+    Start = S.Start;
+    End = S.End;
+    Offset = S.Offset;
+    BuildIdSize = S.BuildIdSize;
+    memcpy(BuildId, S.BuildId, S.BuildIdSize);
+    return *this;
+  }
+
+  bool operator==(const SegmentEntry& S) const {
+    return Start == S.Start && End == S.End && Offset == S.Offset &&
+           BuildIdSize == S.BuildIdSize &&
+           memcmp(BuildId, S.BuildId, S.BuildIdSize) == 0;
+  }
+});
+
+// Packed struct definition for MSVC. We can't use the PACKED macro defined in
+// MemProfData.inc since it would mean we are embedding a directive (the
+// #include for MIBEntryDef) into the macros which is undefined behaviour.
+#ifdef _MSC_VER
+__pragma(pack(push,1))
+#endif
+
+// A struct representing the heap allocation characteristics of a particular
+// runtime context. This struct is shared between the compiler-rt runtime and
+// the raw profile reader. The indexed format uses a separate, self-describing
+// backwards compatible format.
+struct MemInfoBlock{
+
+#define MIBEntryDef(NameTag, Name, Type) Type Name;
+#include "MIBEntryDef.inc"
+#undef MIBEntryDef
+
+bool operator==(const MemInfoBlock& Other) const {
+  bool IsEqual = true;
+#define MIBEntryDef(NameTag, Name, Type) \
+  IsEqual = (IsEqual && Name == Other.Name);
+#include "MIBEntryDef.inc"
+#undef MIBEntryDef
+  return IsEqual;
+}
+
+MemInfoBlock() {
+#define MIBEntryDef(NameTag, Name, Type) Name = Type();
+#include "MIBEntryDef.inc"
+#undef MIBEntryDef
+}
+
+MemInfoBlock(uint32_t Size, uint64_t AccessCount, uint32_t AllocTs,
+             uint32_t DeallocTs, uint32_t AllocCpu, uint32_t DeallocCpu,
+             uintptr_t Histogram, uint32_t HistogramSize)
+    : MemInfoBlock() {
+  AllocCount = 1U;
+  TotalAccessCount = AccessCount;
+  MinAccessCount = AccessCount;
+  MaxAccessCount = AccessCount;
+  TotalSize = Size;
+  MinSize = Size;
+  MaxSize = Size;
+  AllocTimestamp = AllocTs;
+  DeallocTimestamp = DeallocTs;
+  TotalLifetime = DeallocTimestamp - AllocTimestamp;
+  MinLifetime = TotalLifetime;
+  MaxLifetime = TotalLifetime;
+  // Access density is accesses per byte. Multiply by 100 to include the
+  // fractional part.
+  TotalAccessDensity = AccessCount * 100 / Size;
+  MinAccessDensity = TotalAccessDensity;
+  MaxAccessDensity = TotalAccessDensity;
+  // Lifetime access density is the access density per second of lifetime.
+  // Multiply by 1000 to convert denominator lifetime to seconds (using a
+  // minimum lifetime of 1ms to avoid divide by 0. Do the multiplication first
+  // to reduce truncations to 0.
+  TotalLifetimeAccessDensity =
+      TotalAccessDensity * 1000 / (TotalLifetime ? TotalLifetime : 1);
+  MinLifetimeAccessDensity = TotalLifetimeAccessDensity;
+  MaxLifetimeAccessDensity = TotalLifetimeAccessDensity;
+  AllocCpuId = AllocCpu;
+  DeallocCpuId = DeallocCpu;
+  NumMigratedCpu = AllocCpuId != DeallocCpuId;
+  AccessHistogramSize = HistogramSize;
+  AccessHistogram = Histogram;
+}
+
+void Merge(const MemInfoBlock &newMIB) {
+  AllocCount += newMIB.AllocCount;
+
+  TotalAccessCount += newMIB.TotalAccessCount;
+  MinAccessCount = newMIB.MinAccessCount < MinAccessCount ? newMIB.MinAccessCount : MinAccessCount;
+  MaxAccessCount = newMIB.MaxAccessCount > MaxAccessCount ? newMIB.MaxAccessCount : MaxAccessCount;
+
+  TotalSize += newMIB.TotalSize;
+  MinSize = newMIB.MinSize < MinSize ? newMIB.MinSize : MinSize;
+  MaxSize = newMIB.MaxSize > MaxSize ? newMIB.MaxSize : MaxSize;
+
+  TotalLifetime += newMIB.TotalLifetime;
+  MinLifetime = newMIB.MinLifetime < MinLifetime ? newMIB.MinLifetime : MinLifetime;
+  MaxLifetime = newMIB.MaxLifetime > MaxLifetime ? newMIB.MaxLifetime : MaxLifetime;
+
+  TotalAccessDensity += newMIB.TotalAccessDensity;
+  MinAccessDensity = newMIB.MinAccessDensity < MinAccessDensity
+                         ? newMIB.MinAccessDensity
+                         : MinAccessDensity;
+  MaxAccessDensity = newMIB.MaxAccessDensity > MaxAccessDensity
+                         ? newMIB.MaxAccessDensity
+                         : MaxAccessDensity;
+
+  TotalLifetimeAccessDensity += newMIB.TotalLifetimeAccessDensity;
+  MinLifetimeAccessDensity =
+      newMIB.MinLifetimeAccessDensity < MinLifetimeAccessDensity
+          ? newMIB.MinLifetimeAccessDensity
+          : MinLifetimeAccessDensity;
+  MaxLifetimeAccessDensity =
+      newMIB.MaxLifetimeAccessDensity > MaxLifetimeAccessDensity
+          ? newMIB.MaxLifetimeAccessDensity
+          : MaxLifetimeAccessDensity;
+
+  // We know newMIB was deallocated later, so just need to check if it was
+  // allocated before last one deallocated.
+  NumLifetimeOverlaps += newMIB.AllocTimestamp < DeallocTimestamp;
+  AllocTimestamp = newMIB.AllocTimestamp;
+  DeallocTimestamp = newMIB.DeallocTimestamp;
+
+  NumSameAllocCpu += AllocCpuId == newMIB.AllocCpuId;
+  NumSameDeallocCpu += DeallocCpuId == newMIB.DeallocCpuId;
+  AllocCpuId = newMIB.AllocCpuId;
+  DeallocCpuId = newMIB.DeallocCpuId;
+
+  // For merging histograms, we always keep the longer histogram, and add
+  // values of shorter histogram to larger one.
+  uintptr_t ShorterHistogram;
+  uint32_t ShorterHistogramSize;
+  if (newMIB.AccessHistogramSize > AccessHistogramSize) {
+    ShorterHistogram = AccessHistogram;
+    ShorterHistogramSize = AccessHistogramSize;
+    // Swap histogram of current to larger histogram
+    AccessHistogram = newMIB.AccessHistogram;
+    AccessHistogramSize = newMIB.AccessHistogramSize;
+  } else {
+    ShorterHistogram = newMIB.AccessHistogram;
+    ShorterHistogramSize = newMIB.AccessHistogramSize;
+  }
+  for (size_t i = 0; i < ShorterHistogramSize; ++i) {
+    ((uint64_t *)AccessHistogram)[i] += ((uint64_t *)ShorterHistogram)[i];
+  }
+}
+
+#ifdef _MSC_VER
+} __pragma(pack(pop));
+#else
+} __attribute__((__packed__));
+#endif
+
+} // namespace memprof
+} // namespace llvm
+
+#endif

system/lib/compiler-rt/include/profile/MemProfData.inc

@@ -0,0 +1,92 @@
+/*===---- instr_prof_interface.h - Instrumentation PGO User Program API ----===
+ *
+ * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+ * See https://llvm.org/LICENSE.txt for license information.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ *
+ *===-----------------------------------------------------------------------===
+ *
+ * This header provides a public interface for fine-grained control of counter
+ * reset and profile dumping. These interface functions can be directly called
+ * in user programs.
+ *
+\*===---------------------------------------------------------------------===*/
+
+#ifndef COMPILER_RT_INSTR_PROFILING
+#define COMPILER_RT_INSTR_PROFILING
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __LLVM_INSTR_PROFILE_GENERATE
+// Profile file reset and dump interfaces.
+// When `-fprofile[-instr]-generate`/`-fcs-profile-generate` is in effect,
+// clang defines __LLVM_INSTR_PROFILE_GENERATE to pick up the API calls.
+
+/*!
+ * \brief Set the filename for writing instrumentation data.
+ *
+ * Sets the filename to be used for subsequent calls to
+ * \a __llvm_profile_write_file().
+ *
+ * \c Name is not copied, so it must remain valid.  Passing NULL resets the
+ * filename logic to the default behaviour.
+ *
+ * Note: There may be multiple copies of the profile runtime (one for each
+ * instrumented image/DSO). This API only modifies the filename within the
+ * copy of the runtime available to the calling image.
+ *
+ * Warning: This is a no-op if continuous mode (\ref
+ * __llvm_profile_is_continuous_mode_enabled) is on. The reason for this is
+ * that in continuous mode, profile counters are mmap()'d to the profile at
+ * program initialization time. Support for transferring the mmap'd profile
+ * counts to a new file has not been implemented.
+ */
+void __llvm_profile_set_filename(const char *Name);
+
+/*!
+ * \brief Interface to set all PGO counters to zero for the current process.
+ *
+ */
+void __llvm_profile_reset_counters(void);
+
+/*!
+ * \brief this is a wrapper interface to \c __llvm_profile_write_file.
+ * After this interface is invoked, an already dumped flag will be set
+ * so that profile won't be dumped again during program exit.
+ * Invocation of interface __llvm_profile_reset_counters will clear
+ * the flag. This interface is designed to be used to collect profile
+ * data from user selected hot regions. The use model is
+ *      __llvm_profile_reset_counters();
+ *      ... hot region 1
+ *      __llvm_profile_dump();
+ *      .. some other code
+ *      __llvm_profile_reset_counters();
+ *      ... hot region 2
+ *      __llvm_profile_dump();
+ *
+ *  It is expected that on-line profile merging is on with \c %m specifier
+ *  used in profile filename . If merging is not turned on, user is expected
+ *  to invoke __llvm_profile_set_filename to specify different profile names
+ *  for different regions before dumping to avoid profile write clobbering.
+ */
+int __llvm_profile_dump(void);
+
+// Interface to dump the current process' order file to disk.
+int __llvm_orderfile_dump(void);
+
+#else
+
+#define __llvm_profile_set_filename(Name)
+#define __llvm_profile_reset_counters()
+#define __llvm_profile_dump() (0)
+#define __llvm_orderfile_dump() (0)
+
+#endif
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif