cmd/vendor: upgrade pprof to latest

This change upgrades the vendored pprof to pick up the fix for a
serious issue that made the source view in browser mode blank
(tracked upstream as google/pprof#621).

I also had to patch pprof.go, since one of the upstream commit we
included introduced a breaking change in the file interface (the Base
method is now called ObjAddr and has a different signature).

I've manually verified that the upgrade fixes the aforementioned
issues with the source view.

Fixes #45786

Change-Id: I00659ae539a2ad603758e1f06572374d483b9ddc
Reviewed-on: https://go-review.googlesource.com/c/go/+/318049
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

14 files changed, 412 insertions, 192 deletions

diff --git a/src/cmd/go.mod b/src/cmd/go.mod
index a15cbe070a..7a96bc6409 100644
--- a/src/cmd/go.mod
+++ b/src/cmd/go.mod
@@ -3,7 +3,7 @@ module cmd
 go 1.17
 
 require (
-	github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5
+	github.com/google/pprof v0.0.0-20210506205249-923b5ab0fc1a
 	github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639 // indirect
 	golang.org/x/arch v0.0.0-20210502124803-cbf565b21d1e
 	golang.org/x/crypto v0.0.0-20210503195802-e9a32991a82e // indirect
diff --git a/src/cmd/go.sum b/src/cmd/go.sum
index 8a7ad4290a..1c6e224820 100644
--- a/src/cmd/go.sum
+++ b/src/cmd/go.sum
@@ -1,8 +1,8 @@
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
-github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5 h1:zIaiqGYDQwa4HVx5wGRTXbx38Pqxjemn4BP98wpzpXo=
-github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
+github.com/google/pprof v0.0.0-20210506205249-923b5ab0fc1a h1:jmAp/2PZAScNd62lTD3Mcb0Ey9FvIIJtLohPhtxZJ+Q=
+github.com/google/pprof v0.0.0-20210506205249-923b5ab0fc1a/go.mod h1:kpwsk12EmLew5upagYY7GY0pfYCcupk39gWOCRROcvE=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639 h1:mV02weKRL81bEnm8A0HT1/CAelMQDBuQIfLw8n+d6xI=
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 golang.org/x/arch v0.0.0-20210502124803-cbf565b21d1e h1:pv3V0NlNSh5Q6AX/StwGLBjcLS7UN4m4Gq+V+uSecqM=
diff --git a/src/cmd/pprof/pprof.go b/src/cmd/pprof/pprof.go
index 11f91cbedb..1d10a7b41f 100644
--- a/src/cmd/pprof/pprof.go
+++ b/src/cmd/pprof/pprof.go
@@ -232,9 +232,9 @@ func (f *file) Name() string {
 	return f.name
 }
 
-func (f *file) Base() uint64 {
+func (f *file) ObjAddr(addr uint64) (uint64, error) {
 	// No support for shared libraries.
-	return 0
+	return 0, nil
 }
 
 func (f *file) BuildID() string {
diff --git a/src/cmd/vendor/github.com/google/pprof/driver/driver.go b/src/cmd/vendor/github.com/google/pprof/driver/driver.go
index e65bc2f417..fc05f919ba 100644
--- a/src/cmd/vendor/github.com/google/pprof/driver/driver.go
+++ b/src/cmd/vendor/github.com/google/pprof/driver/driver.go
@@ -159,8 +159,8 @@ type ObjFile interface {
 	// Name returns the underlying file name, if available.
 	Name() string
 
-	// Base returns the base address to use when looking up symbols in the file.
-	Base() uint64
+	// ObjAddr returns the objdump address corresponding to a runtime address.
+	ObjAddr(addr uint64) (uint64, error)
 
 	// BuildID returns the GNU build ID of the file, or an empty string.
 	BuildID() string
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/binutils/binutils.go b/src/cmd/vendor/github.com/google/pprof/internal/binutils/binutils.go
index 576a6ee66a..5ed8a1f9f1 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/binutils/binutils.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/binutils/binutils.go
@@ -42,7 +42,12 @@ type Binutils struct {
 	rep *binrep
 }
 
-var objdumpLLVMVerRE = regexp.MustCompile(`LLVM version (?:(\d*)\.(\d*)\.(\d*)|.*(trunk).*)`)
+var (
+	objdumpLLVMVerRE = regexp.MustCompile(`LLVM version (?:(\d*)\.(\d*)\.(\d*)|.*(trunk).*)`)
+
+	// Defined for testing
+	elfOpen = elf.Open
+)
 
 // binrep is an immutable representation for Binutils.  It is atomically
 // replaced on every mutation to provide thread-safe access.
@@ -421,14 +426,23 @@ func (b *binrep) openMachO(name string, start, limit, offset uint64) (plugin.Obj
 }
 
 func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFile, error) {
-	ef, err := elf.Open(name)
+	ef, err := elfOpen(name)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing %s: %v", name, err)
 	}
 	defer ef.Close()
 
-	var stextOffset *uint64
-	var pageAligned = func(addr uint64) bool { return addr%4096 == 0 }
+	buildID := ""
+	if f, err := os.Open(name); err == nil {
+		if id, err := elfexec.GetBuildID(f); err == nil {
+			buildID = fmt.Sprintf("%x", id)
+		}
+	}
+
+	var (
+		stextOffset *uint64
+		pageAligned = func(addr uint64) bool { return addr%4096 == 0 }
+	)
 	if strings.Contains(name, "vmlinux") || !pageAligned(start) || !pageAligned(limit) || !pageAligned(offset) {
 		// Reading all Symbols is expensive, and we only rarely need it so
 		// we don't want to do it every time. But if _stext happens to be
@@ -450,38 +464,29 @@ func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFi
 		}
 	}
 
-	var ph *elf.ProgHeader
-	// For user space executables, find the actual program segment that is
-	// associated with the given mapping. Skip this search if limit <= start.
-	// We cannot use just a check on the start address of the mapping to tell if
-	// it's a kernel / .ko module mapping, because with quipper address remapping
-	// enabled, the address would be in the lower half of the address space.
-	if stextOffset == nil && start < limit && limit < (uint64(1)<<63) {
-		ph, err = elfexec.FindProgHeaderForMapping(ef, offset, limit-start)
-		if err != nil {
-			return nil, fmt.Errorf("failed to find program header for file %q, mapping pgoff %x, memsz=%x: %v", name, offset, limit-start, err)
-		}
-	} else {
-		// For the kernel, find the program segment that includes the .text section.
-		ph = elfexec.FindTextProgHeader(ef)
-	}
-
-	base, err := elfexec.GetBase(&ef.FileHeader, ph, stextOffset, start, limit, offset)
-	if err != nil {
+	// Check that we can compute a base for the binary. This may not be the
+	// correct base value, so we don't save it. We delay computing the actual base
+	// value until we have a sample address for this mapping, so that we can
+	// correctly identify the associated program segment that is needed to compute
+	// the base.
+	if _, err := elfexec.GetBase(&ef.FileHeader, elfexec.FindTextProgHeader(ef), stextOffset, start, limit, offset); err != nil {
 		return nil, fmt.Errorf("could not identify base for %s: %v", name, err)
 	}
 
-	buildID := ""
-	if f, err := os.Open(name); err == nil {
-		if id, err := elfexec.GetBuildID(f); err == nil {
-			buildID = fmt.Sprintf("%x", id)
-		}
-	}
-	isData := ph != nil && ph.Flags&elf.PF_X == 0
 	if b.fast || (!b.addr2lineFound && !b.llvmSymbolizerFound) {
-		return &fileNM{file: file{b, name, base, buildID, isData}}, nil
+		return &fileNM{file: file{
+			b:       b,
+			name:    name,
+			buildID: buildID,
+			m:       &elfMapping{start: start, limit: limit, offset: offset, stextOffset: stextOffset},
+		}}, nil
 	}
-	return &fileAddr2Line{file: file{b, name, base, buildID, isData}}, nil
+	return &fileAddr2Line{file: file{
+		b:       b,
+		name:    name,
+		buildID: buildID,
+		m:       &elfMapping{start: start, limit: limit, offset: offset, stextOffset: stextOffset},
+	}}, nil
 }
 
 func (b *binrep) openPE(name string, start, limit, offset uint64) (plugin.ObjFile, error) {
@@ -511,21 +516,119 @@ func (b *binrep) openPE(name string, start, limit, offset uint64) (plugin.ObjFil
 	return &fileAddr2Line{file: file{b: b, name: name, base: base}}, nil
 }
 
+// elfMapping stores the parameters of a runtime mapping that are needed to
+// identify the ELF segment associated with a mapping.
+type elfMapping struct {
+	// Runtime mapping parameters.
+	start, limit, offset uint64
+	// Offset of _stext symbol. Only defined for kernel images, nil otherwise.
+	stextOffset *uint64
+}
+
 // file implements the binutils.ObjFile interface.
 type file struct {
 	b       *binrep
 	name    string
-	base    uint64
 	buildID string
-	isData  bool
+
+	baseOnce sync.Once // Ensures the base, baseErr and isData are computed once.
+	base     uint64
+	baseErr  error // Any eventual error while computing the base.
+	isData   bool
+	// Mapping information. Relevant only for ELF files, nil otherwise.
+	m *elfMapping
+}
+
+// computeBase computes the relocation base for the given binary file only if
+// the elfMapping field is set. It populates the base and isData fields and
+// returns an error.
+func (f *file) computeBase(addr uint64) error {
+	if f == nil || f.m == nil {
+		return nil
+	}
+	if addr < f.m.start || addr >= f.m.limit {
+		return fmt.Errorf("specified address %x is outside the mapping range [%x, %x] for file %q", addr, f.m.start, f.m.limit, f.name)
+	}
+	ef, err := elfOpen(f.name)
+	if err != nil {
+		return fmt.Errorf("error parsing %s: %v", f.name, err)
+	}
+	defer ef.Close()
+
+	var ph *elf.ProgHeader
+	// For user space executables, find the actual program segment that is
+	// associated with the given mapping. Skip this search if limit <= start.
+	// We cannot use just a check on the start address of the mapping to tell if
+	// it's a kernel / .ko module mapping, because with quipper address remapping
+	// enabled, the address would be in the lower half of the address space.
+	if f.m.stextOffset == nil && f.m.start < f.m.limit && f.m.limit < (uint64(1)<<63) {
+		// Get all program headers associated with the mapping.
+		headers, hasLoadables := elfexec.ProgramHeadersForMapping(ef, f.m.offset, f.m.limit-f.m.start)
+
+		// Some ELF files don't contain any loadable program segments, e.g. .ko
+		// kernel modules. It's not an error to have no header in such cases.
+		if hasLoadables {
+			ph, err = matchUniqueHeader(headers, addr-f.m.start+f.m.offset)
+			if err != nil {
+				return fmt.Errorf("failed to find program header for file %q, ELF mapping %#v, address %x: %v", f.name, *f.m, addr, err)
+			}
+		}
+	} else {
+		// For the kernel, find the program segment that includes the .text section.
+		ph = elfexec.FindTextProgHeader(ef)
+	}
+
+	base, err := elfexec.GetBase(&ef.FileHeader, ph, f.m.stextOffset, f.m.start, f.m.limit, f.m.offset)
+	if err != nil {
+		return err
+	}
+	f.base = base
+	f.isData = ph != nil && ph.Flags&elf.PF_X == 0
+	return nil
+}
+
+// matchUniqueHeader attempts to identify a unique header from the given list,
+// using the given file offset to disambiguate between multiple segments. It
+// returns an error if the header list is empty or if it cannot identify a
+// unique header.
+func matchUniqueHeader(headers []*elf.ProgHeader, fileOffset uint64) (*elf.ProgHeader, error) {
+	if len(headers) == 0 {
+		return nil, errors.New("no program header matches mapping info")
+	}
+	if len(headers) == 1 {
+		// Don't use the file offset if we already have a single header.
+		return headers[0], nil
+	}
+	// We have multiple input segments. Attempt to identify a unique one
+	// based on the given file offset.
+	var ph *elf.ProgHeader
+	for _, h := range headers {
+		if fileOffset >= h.Off && fileOffset < h.Off+h.Memsz {
+			if ph != nil {
+				// Assuming no other bugs, this can only happen if we have two or
+				// more small program segments that fit on the same page, and a
+				// segment other than the last one includes uninitialized data.
+				return nil, fmt.Errorf("found second program header (%#v) that matches file offset %x, first program header is %#v. Does first program segment contain uninitialized data?", *h, fileOffset, *ph)
+			}
+			ph = h
+		}
+	}
+	if ph == nil {
+		return nil, fmt.Errorf("no program header matches file offset %x", fileOffset)
+	}
+	return ph, nil
 }
 
 func (f *file) Name() string {
 	return f.name
 }
 
-func (f *file) Base() uint64 {
-	return f.base
+func (f *file) ObjAddr(addr uint64) (uint64, error) {
+	f.baseOnce.Do(func() { f.baseErr = f.computeBase(addr) })
+	if f.baseErr != nil {
+		return 0, f.baseErr
+	}
+	return addr - f.base, nil
 }
 
 func (f *file) BuildID() string {
@@ -533,7 +636,11 @@ func (f *file) BuildID() string {
 }
 
 func (f *file) SourceLine(addr uint64) ([]plugin.Frame, error) {
-	return []plugin.Frame{}, nil
+	f.baseOnce.Do(func() { f.baseErr = f.computeBase(addr) })
+	if f.baseErr != nil {
+		return nil, f.baseErr
+	}
+	return nil, nil
 }
 
 func (f *file) Close() error {
@@ -560,6 +667,10 @@ type fileNM struct {
 }
 
 func (f *fileNM) SourceLine(addr uint64) ([]plugin.Frame, error) {
+	f.baseOnce.Do(func() { f.baseErr = f.computeBase(addr) })
+	if f.baseErr != nil {
+		return nil, f.baseErr
+	}
 	if f.addr2linernm == nil {
 		addr2liner, err := newAddr2LinerNM(f.b.nm, f.name, f.base)
 		if err != nil {
@@ -579,9 +690,14 @@ type fileAddr2Line struct {
 	file
 	addr2liner     *addr2Liner
 	llvmSymbolizer *llvmSymbolizer
+	isData         bool
 }
 
 func (f *fileAddr2Line) SourceLine(addr uint64) ([]plugin.Frame, error) {
+	f.baseOnce.Do(func() { f.baseErr = f.computeBase(addr) })
+	if f.baseErr != nil {
+		return nil, f.baseErr
+	}
 	f.once.Do(f.init)
 	if f.llvmSymbolizer != nil {
 		return f.llvmSymbolizer.addrInfo(addr)
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/elfexec/elfexec.go b/src/cmd/vendor/github.com/google/pprof/internal/elfexec/elfexec.go
index 3b3c6ee89f..2638b2db2d 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/elfexec/elfexec.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/elfexec/elfexec.go
@@ -284,83 +284,71 @@ func FindTextProgHeader(f *elf.File) *elf.ProgHeader {
 	return nil
 }
 
-// FindProgHeaderForMapping returns the loadable program segment header that is
-// fully contained in the runtime mapping with file offset pgoff and memory size
-// memsz, or an error if the segment cannot be determined. The function returns
-// a nil program header and no error if the ELF binary has no loadable segments.
-func FindProgHeaderForMapping(f *elf.File, pgoff, memsz uint64) (*elf.ProgHeader, error) {
+// ProgramHeadersForMapping returns the loadable program segment headers that
+// are fully contained in the runtime mapping with file offset pgoff and memory
+// size memsz, and if the binary includes any loadable segments.
+func ProgramHeadersForMapping(f *elf.File, pgoff, memsz uint64) ([]*elf.ProgHeader, bool) {
+	const (
+		// pageSize defines the virtual memory page size used by the loader. This
+		// value is dependent on the memory management unit of the CPU. The page
+		// size is 4KB virtually on all the architectures that we care about, so we
+		// define this metric as a constant. If we encounter architectures where
+		// page sie is not 4KB, we must try to guess the page size on the system
+		// where the profile was collected, possibly using the architecture
+		// specified in the ELF file header.
+		pageSize       = 4096
+		pageOffsetMask = pageSize - 1
+		pageMask       = ^uint64(pageOffsetMask)
+	)
 	var headers []*elf.ProgHeader
-	loadables := 0
+	hasLoadables := false
 	for _, p := range f.Progs {
+		// The segment must be fully included in the mapping.
 		if p.Type == elf.PT_LOAD && pgoff <= p.Off && p.Off+p.Memsz <= pgoff+memsz {
-			headers = append(headers, &p.ProgHeader)
+			alignedOffset := uint64(0)
+			if p.Off > (p.Vaddr & pageOffsetMask) {
+				alignedOffset = p.Off - (p.Vaddr & pageOffsetMask)
+			}
+			if alignedOffset <= pgoff {
+				headers = append(headers, &p.ProgHeader)
+			}
 		}
 		if p.Type == elf.PT_LOAD {
-			loadables++
+			hasLoadables = true
 		}
 	}
-	if len(headers) == 1 {
-		return headers[0], nil
+	if len(headers) < 2 {
+		return headers, hasLoadables
 	}
-	// Some ELF files don't contain any program segments, e.g. .ko loadable kernel
-	// modules. Don't return an error in such cases.
-	if loadables == 0 {
-		return nil, nil
-	}
-	if len(headers) == 0 {
-		return nil, fmt.Errorf("no program header matches file offset %x and memory size %x", pgoff, memsz)
-	}
-
-	// Segments are mapped page aligned. In some cases, segments may be smaller
-	// than a page, which causes the next segment to start at a file offset that
-	// is logically on the same page if we were to align file offsets by page.
-	// Example:
-	//  LOAD           0x0000000000000000 0x0000000000400000 0x0000000000400000
-	//                 0x00000000000006fc 0x00000000000006fc  R E    0x200000
-	//  LOAD           0x0000000000000e10 0x0000000000600e10 0x0000000000600e10
-	//                 0x0000000000000230 0x0000000000000238  RW     0x200000
-	//
-	// In this case, perf records the following mappings for this executable:
-	// 0 0 [0xc0]: PERF_RECORD_MMAP2 87867/87867: [0x400000(0x1000) @ 0 00:3c 512041 0]: r-xp exename
-	// 0 0 [0xc0]: PERF_RECORD_MMAP2 87867/87867: [0x600000(0x2000) @ 0 00:3c 512041 0]: rw-p exename
-	//
-	// Both mappings have file offset 0. The first mapping is one page length and
-	// it can include only the first loadable segment. Due to page alignment, the
-	// second mapping starts also at file offset 0, and it spans two pages. It can
-	// include both the first and the second loadable segments. We must return the
-	// correct program header to compute the correct base offset.
-	//
-	// We cannot use the mapping protections to distinguish between segments,
-	// because protections are not passed through to this function.
-	// We cannot use the start address to differentiate between segments, because
-	// with ASLR, the mapping start address can be any value.
-	//
-	// We use a heuristic to compute the minimum mapping size required for a
-	// segment, assuming mappings are 4k page aligned, and return the segment that
-	// matches the given mapping size.
-	const pageSize = 4096
 
+	// If we have more than one matching segments, try a strict check on the
+	// segment memory size. We use a heuristic to compute the minimum mapping size
+	// required for a segment, assuming mappings are page aligned.
 	// The memory size based heuristic makes sense only if the mapping size is a
-	// multiple of 4k page size.
+	// multiple of page size.
 	if memsz%pageSize != 0 {
-		return nil, fmt.Errorf("mapping size = %x and %d segments match the passed in mapping", memsz, len(headers))
+		return headers, hasLoadables
 	}
 
-	// Return an error if no segment, or multiple segments match the size, so we can debug.
+	// Return all found headers if we cannot narrow the selection to a single
+	// program segment.
 	var ph *elf.ProgHeader
-	pageMask := ^uint64(pageSize - 1)
 	for _, h := range headers {
 		wantSize := (h.Vaddr+h.Memsz+pageSize-1)&pageMask - (h.Vaddr & pageMask)
 		if wantSize != memsz {
 			continue
 		}
 		if ph != nil {
-			return nil, fmt.Errorf("found second program header (%#v) that matches memsz %x, first program header is %#v", *h, memsz, *ph)
+			// Found a second program header matching, so return all previously
+			// identified headers.
+			return headers, hasLoadables
 		}
 		ph = h
 	}
 	if ph == nil {
-		return nil, fmt.Errorf("found %d matching program headers, but none matches mapping size %x", len(headers), memsz)
+		// No matching header for the strict check. Return all previously identified
+		// headers.
+		return headers, hasLoadables
 	}
-	return ph, nil
+	return []*elf.ProgHeader{ph}, hasLoadables
 }
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/plugin/plugin.go b/src/cmd/vendor/github.com/google/pprof/internal/plugin/plugin.go
index 3a8d0af730..a57a0b20a9 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/plugin/plugin.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/plugin/plugin.go
@@ -131,8 +131,9 @@ type ObjFile interface {
 	// Name returns the underlyinf file name, if available
 	Name() string
 
-	// Base returns the base address to use when looking up symbols in the file.
-	Base() uint64
+	// ObjAddr returns the objdump (linker) address corresponding to a runtime
+	// address, and an error.
+	ObjAddr(addr uint64) (uint64, error)
 
 	// BuildID returns the GNU build ID of the file, or an empty string.
 	BuildID() string
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/report.go b/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
index bc5685d61e..4a86554880 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/report.go
@@ -445,7 +445,7 @@ func PrintAssembly(w io.Writer, rpt *Report, obj plugin.ObjTool, maxFuncs int) e
 			return err
 		}
 
-		ns := annotateAssembly(insts, sns, s.base)
+		ns := annotateAssembly(insts, sns, s.file)
 
 		fmt.Fprintf(w, "ROUTINE ======================== %s\n", s.sym.Name[0])
 		for _, name := range s.sym.Name[1:] {
@@ -534,7 +534,6 @@ func symbolsFromBinaries(prof *profile.Profile, g *graph.Graph, rx *regexp.Regex
 			addr = *address
 		}
 		msyms, err := f.Symbols(rx, addr)
-		base := f.Base()
 		f.Close()
 		if err != nil {
 			continue
@@ -543,7 +542,6 @@ func symbolsFromBinaries(prof *profile.Profile, g *graph.Graph, rx *regexp.Regex
 			objSyms = append(objSyms,
 				&objSymbol{
 					sym:  ms,
-					base: base,
 					file: f,
 				},
 			)
@@ -558,7 +556,6 @@ func symbolsFromBinaries(prof *profile.Profile, g *graph.Graph, rx *regexp.Regex
 // added to correspond to sample addresses
 type objSymbol struct {
 	sym  *plugin.Sym
-	base uint64
 	file plugin.ObjFile
 }
 
@@ -578,8 +575,7 @@ func nodesPerSymbol(ns graph.Nodes, symbols []*objSymbol) map[*objSymbol]graph.N
 	for _, s := range symbols {
 		// Gather samples for this symbol.
 		for _, n := range ns {
-			address := n.Info.Address - s.base
-			if address >= s.sym.Start && address < s.sym.End {
+			if address, err := s.file.ObjAddr(n.Info.Address); err == nil && address >= s.sym.Start && address < s.sym.End {
 				symNodes[s] = append(symNodes[s], n)
 			}
 		}
@@ -621,7 +617,7 @@ func (a *assemblyInstruction) cumValue() int64 {
 // annotateAssembly annotates a set of assembly instructions with a
 // set of samples. It returns a set of nodes to display. base is an
 // offset to adjust the sample addresses.
-func annotateAssembly(insts []plugin.Inst, samples graph.Nodes, base uint64) []assemblyInstruction {
+func annotateAssembly(insts []plugin.Inst, samples graph.Nodes, file plugin.ObjFile) []assemblyInstruction {
 	// Add end marker to simplify printing loop.
 	insts = append(insts, plugin.Inst{
 		Addr: ^uint64(0),
@@ -645,7 +641,10 @@ func annotateAssembly(insts []plugin.Inst, samples graph.Nodes, base uint64) []a
 
 		// Sum all the samples until the next instruction (to account
 		// for samples attributed to the middle of an instruction).
-		for next := insts[ix+1].Addr; s < len(samples) && samples[s].Info.Address-base < next; s++ {
+		for next := insts[ix+1].Addr; s < len(samples); s++ {
+			if addr, err := file.ObjAddr(samples[s].Info.Address); err != nil || addr >= next {
+				break
+			}
 			sample := samples[s]
 			n.flatDiv += sample.FlatDiv
 			n.flat += sample.Flat
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/source.go b/src/cmd/vendor/github.com/google/pprof/internal/report/source.go
index 4f841eff5d..54245e5f9e 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/report/source.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/source.go
@@ -132,6 +132,7 @@ func printWebSource(w io.Writer, rpt *Report, obj plugin.ObjTool) error {
 // sourcePrinter holds state needed for generating source+asm HTML listing.
 type sourcePrinter struct {
 	reader     *sourceReader
+	synth      *synthCode
 	objectTool plugin.ObjTool
 	objects    map[string]plugin.ObjFile  // Opened object files
 	sym        *regexp.Regexp             // May be nil
@@ -146,6 +147,12 @@ type sourcePrinter struct {
 	prettyNames map[string]string
 }
 
+// addrInfo holds information for an address we are interested in.
+type addrInfo struct {
+	loc *profile.Location // Always non-nil
+	obj plugin.ObjFile    // May be nil
+}
+
 // instructionInfo holds collected information for an instruction.
 type instructionInfo struct {
 	objAddr   uint64 // Address in object file (with base subtracted out)
@@ -207,6 +214,7 @@ func PrintWebList(w io.Writer, rpt *Report, obj plugin.ObjTool, maxFiles int) er
 func newSourcePrinter(rpt *Report, obj plugin.ObjTool, sourcePath string) *sourcePrinter {
 	sp := &sourcePrinter{
 		reader:      newSourceReader(sourcePath, rpt.options.TrimPath),
+		synth:       newSynthCode(rpt.prof.Mapping),
 		objectTool:  obj,
 		objects:     map[string]plugin.ObjFile{},
 		sym:         rpt.options.Symbol,
@@ -225,19 +233,21 @@ func newSourcePrinter(rpt *Report, obj plugin.ObjTool, sourcePath string) *sourc
 		}
 	}
 
-	addrs := map[uint64]bool{}
+	addrs := map[uint64]addrInfo{}
 	flat := map[uint64]int64{}
 	cum := map[uint64]int64{}
 
 	// Record an interest in the function corresponding to lines[index].
-	markInterest := func(addr uint64, lines []profile.Line, index int) {
-		fn := lines[index]
+	markInterest := func(addr uint64, loc *profile.Location, index int) {
+		fn := loc.Line[index]
 		if fn.Function == nil {
 			return
 		}
 		sp.interest[fn.Function.Name] = true
 		sp.interest[fn.Function.SystemName] = true
-		addrs[addr] = true
+		if _, ok := addrs[addr]; !ok {
+			addrs[addr] = addrInfo{loc, sp.objectFile(loc.Mapping)}
+		}
 	}
 
 	// See if sp.sym matches line.
@@ -270,15 +280,21 @@ func newSourcePrinter(rpt *Report, obj plugin.ObjTool, sourcePath string) *sourc
 				sp.prettyNames[line.Function.SystemName] = line.Function.Name
 			}
 
-			cum[loc.Address] += value
+			addr := loc.Address
+			if addr == 0 {
+				// Some profiles are missing valid addresses.
+				addr = sp.synth.address(loc)
+			}
+
+			cum[addr] += value
 			if i == 0 {
-				flat[loc.Address] += value
+				flat[addr] += value
 			}
 
-			if sp.sym == nil || (address != nil && loc.Address == *address) {
+			if sp.sym == nil || (address != nil && addr == *address) {
 				// Interested in top-level entry of stack.
 				if len(loc.Line) > 0 {
-					markInterest(loc.Address, loc.Line, len(loc.Line)-1)
+					markInterest(addr, loc, len(loc.Line)-1)
 				}
 				continue
 			}
@@ -287,7 +303,7 @@ func newSourcePrinter(rpt *Report, obj plugin.ObjTool, sourcePath string) *sourc
 			matchFile := (loc.Mapping != nil && sp.sym.MatchString(loc.Mapping.File))
 			for j, line := range loc.Line {
 				if (j == 0 && matchFile) || matches(line) {
-					markInterest(loc.Address, loc.Line, j)
+					markInterest(addr, loc, j)
 				}
 			}
 		}
@@ -306,10 +322,11 @@ func (sp *sourcePrinter) close() {
 	}
 }
 
-func (sp *sourcePrinter) expandAddresses(rpt *Report, addrs map[uint64]bool, flat map[uint64]int64) {
+func (sp *sourcePrinter) expandAddresses(rpt *Report, addrs map[uint64]addrInfo, flat map[uint64]int64) {
 	// We found interesting addresses (ones with non-zero samples) above.
 	// Get covering address ranges and disassemble the ranges.
-	ranges := sp.splitIntoRanges(rpt.prof, addrs, flat)
+	ranges, unprocessed := sp.splitIntoRanges(rpt.prof, addrs, flat)
+	sp.handleUnprocessed(addrs, unprocessed)
 
 	// Trim ranges if there are too many.
 	const maxRanges = 25
@@ -321,9 +338,18 @@ func (sp *sourcePrinter) expandAddresses(rpt *Report, addrs map[uint64]bool, fla
 	}
 
 	for _, r := range ranges {
-		base := r.obj.Base()
-		insts, err := sp.objectTool.Disasm(r.mapping.File, r.begin-base, r.end-base,
-			rpt.options.IntelSyntax)
+		objBegin, err := r.obj.ObjAddr(r.begin)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to compute objdump address for range start %x: %v\n", r.begin, err)
+			continue
+		}
+		objEnd, err := r.obj.ObjAddr(r.end)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to compute objdump address for range end %x: %v\n", r.end, err)
+			continue
+		}
+		base := r.begin - objBegin
+		insts, err := sp.objectTool.Disasm(r.mapping.File, objBegin, objEnd, rpt.options.IntelSyntax)
 		if err != nil {
 			// TODO(sanjay): Report that the covered addresses are missing.
 			continue
@@ -385,78 +411,115 @@ func (sp *sourcePrinter) expandAddresses(rpt *Report, addrs map[uint64]bool, fla
 				frames = lastFrames
 			}
 
-			// See if the stack contains a function we are interested in.
-			for i, f := range frames {
-				if !sp.interest[f.Func] {
-					continue
-				}
+			sp.addStack(addr, frames)
+		}
+	}
+}
 
-				// Record sub-stack under frame's file/line.
-				fname := canonicalizeFileName(f.File)
-				file := sp.files[fname]
-				if file == nil {
-					file = &sourceFile{
-						fname:    fname,
-						lines:    map[int][]sourceInst{},
-						funcName: map[int]string{},
-					}
-					sp.files[fname] = file
-				}
-				callees := frames[:i]
-				stack := make([]callID, 0, len(callees))
-				for j := len(callees) - 1; j >= 0; j-- { // Reverse so caller is first
-					stack = append(stack, callID{
-						file: callees[j].File,
-						line: callees[j].Line,
-					})
-				}
-				file.lines[f.Line] = append(file.lines[f.Line], sourceInst{addr, stack})
+func (sp *sourcePrinter) addStack(addr uint64, frames []plugin.Frame) {
+	// See if the stack contains a function we are interested in.
+	for i, f := range frames {
+		if !sp.interest[f.Func] {
+			continue
+		}
 
-				// Remember the first function name encountered per source line
-				// and assume that that line belongs to that function.
-				if _, ok := file.funcName[f.Line]; !ok {
-					file.funcName[f.Line] = f.Func
-				}
+		// Record sub-stack under frame's file/line.
+		fname := canonicalizeFileName(f.File)
+		file := sp.files[fname]
+		if file == nil {
+			file = &sourceFile{
+				fname:    fname,
+				lines:    map[int][]sourceInst{},
+				funcName: map[int]string{},
 			}
+			sp.files[fname] = file
+		}
+		callees := frames[:i]
+		stack := make([]callID, 0, len(callees))
+		for j := len(callees) - 1; j >= 0; j-- { // Reverse so caller is first
+			stack = append(stack, callID{
+				file: callees[j].File,
+				line: callees[j].Line,
+			})
+		}
+		file.lines[f.Line] = append(file.lines[f.Line], sourceInst{addr, stack})
+
+		// Remember the first function name encountered per source line
+		// and assume that that line belongs to that function.
+		if _, ok := file.funcName[f.Line]; !ok {
+			file.funcName[f.Line] = f.Func
 		}
 	}
 }
 
-// splitIntoRanges converts the set of addresses we are interested in into a set of address
-// ranges to disassemble.
-func (sp *sourcePrinter) splitIntoRanges(prof *profile.Profile, set map[uint64]bool, flat map[uint64]int64) []addressRange {
-	// List of mappings so we can stop expanding address ranges at mapping boundaries.
-	mappings := append([]*profile.Mapping{}, prof.Mapping...)
-	sort.Slice(mappings, func(i, j int) bool { return mappings[i].Start < mappings[j].Start })
+// synthAsm is the special disassembler value used for instructions without an object file.
+const synthAsm = ""
+
+// handleUnprocessed handles addresses that were skipped by splitIntoRanges because they
+// did not belong to a known object file.
+func (sp *sourcePrinter) handleUnprocessed(addrs map[uint64]addrInfo, unprocessed []uint64) {
+	// makeFrames synthesizes a []plugin.Frame list for the specified address.
+	// The result will typically have length 1, but may be longer if address corresponds
+	// to inlined calls.
+	makeFrames := func(addr uint64) []plugin.Frame {
+		loc := addrs[addr].loc
+		stack := make([]plugin.Frame, 0, len(loc.Line))
+		for _, line := range loc.Line {
+			fn := line.Function
+			if fn == nil {
+				continue
+			}
+			stack = append(stack, plugin.Frame{
+				Func: fn.Name,
+				File: fn.Filename,
+				Line: int(line.Line),
+			})
+		}
+		return stack
+	}
 
-	var result []addressRange
-	addrs := make([]uint64, 0, len(set))
-	for addr := range set {
-		addrs = append(addrs, addr)
+	for _, addr := range unprocessed {
+		frames := makeFrames(addr)
+		x := instructionInfo{
+			objAddr: addr,
+			length:  1,
+			disasm:  synthAsm,
+		}
+		if len(frames) > 0 {
+			x.file = frames[0].File
+			x.line = frames[0].Line
+		}
+		sp.insts[addr] = x
+
+		sp.addStack(addr, frames)
+	}
+}
+
+// splitIntoRanges converts the set of addresses we are interested in into a set of address
+// ranges to disassemble. It also returns the set of addresses found that did not have an
+// associated object file and were therefore not added to an address range.
+func (sp *sourcePrinter) splitIntoRanges(prof *profile.Profile, addrMap map[uint64]addrInfo, flat map[uint64]int64) ([]addressRange, []uint64) {
+	// Partition addresses into two sets: ones with a known object file, and ones without.
+	var addrs, unprocessed []uint64
+	for addr, info := range addrMap {
+		if info.obj != nil {
+			addrs = append(addrs, addr)
+		} else {
+			unprocessed = append(unprocessed, addr)
+		}
 	}
 	sort.Slice(addrs, func(i, j int) bool { return addrs[i] < addrs[j] })
 
-	mappingIndex := 0
 	const expand = 500 // How much to expand range to pick up nearby addresses.
+	var result []addressRange
 	for i, n := 0, len(addrs); i < n; {
 		begin, end := addrs[i], addrs[i]
 		sum := flat[begin]
 		i++
 
-		// Advance to mapping containing addrs[i]
-		for mappingIndex < len(mappings) && mappings[mappingIndex].Limit <= begin {
-			mappingIndex++
-		}
-		if mappingIndex >= len(mappings) {
-			// TODO(sanjay): Report missed address and its samples.
-			break
-		}
-		m := mappings[mappingIndex]
-		obj := sp.objectFile(m)
-		if obj == nil {
-			// TODO(sanjay): Report missed address and its samples.
-			continue
-		}
+		info := addrMap[begin]
+		m := info.loc.Mapping
+		obj := info.obj // Non-nil because of the partitioning done above.
 
 		// Find following addresses that are close enough to addrs[i].
 		for i < n && addrs[i] <= end+2*expand && addrs[i] < m.Limit {
@@ -479,7 +542,7 @@ func (sp *sourcePrinter) splitIntoRanges(prof *profile.Profile, set map[uint64]b
 
 		result = append(result, addressRange{begin, end, obj, m, sum})
 	}
-	return result
+	return result, unprocessed
 }
 
 func (sp *sourcePrinter) initSamples(flat, cum map[uint64]int64) {
@@ -665,9 +728,12 @@ func (sp *sourcePrinter) functions(f *sourceFile) []sourceFunction {
 	return funcs
 }
 
-// objectFile return the object for the named file, opening it if necessary.
+// objectFile return the object for the specified mapping, opening it if necessary.
 // It returns nil on error.
 func (sp *sourcePrinter) objectFile(m *profile.Mapping) plugin.ObjFile {
+	if m == nil {
+		return nil
+	}
 	if object, ok := sp.objects[m.File]; ok {
 		return object // May be nil if we detected an error earlier.
 	}
@@ -725,12 +791,28 @@ func printFunctionSourceLine(w io.Writer, lineNo int, flat, cum int64, lineConte
 		return
 	}
 
+	nestedInfo := false
+	cl := "deadsrc"
+	for _, an := range assembly {
+		if len(an.inlineCalls) > 0 || an.instruction != synthAsm {
+			nestedInfo = true
+			cl = "livesrc"
+		}
+	}
+
 	fmt.Fprintf(w,
-		"<span class=line> %6d</span> <span class=deadsrc>  %10s %10s %8s  %s </span>",
-		lineNo,
+		"<span class=line> %6d</span> <span class=%s>  %10s %10s %8s  %s </span>",
+		lineNo, cl,
 		valueOrDot(flat, rpt), valueOrDot(cum, rpt),
 		"", template.HTMLEscapeString(lineContents))
-	srcIndent := indentation(lineContents)
+	if nestedInfo {
+		srcIndent := indentation(lineContents)
+		printNested(w, srcIndent, assembly, reader, rpt)
+	}
+	fmt.Fprintln(w)
+}
+
+func printNested(w io.Writer, srcIndent int, assembly []assemblyInstruction, reader *sourceReader, rpt *Report) {
 	fmt.Fprint(w, "<span class=asm>")
 	var curCalls []callID
 	for i, an := range assembly {
@@ -763,6 +845,9 @@ func printFunctionSourceLine(w io.Writer, lineNo int, flat, cum int64, lineConte
 				template.HTMLEscapeString(filepath.Base(c.file)), c.line)
 		}
 		curCalls = an.inlineCalls
+		if an.instruction == synthAsm {
+			continue
+		}
 		text := strings.Repeat(" ", srcIndent+4+4*len(curCalls)) + an.instruction
 		fmt.Fprintf(w, " %8s %10s %10s %8x: %s <span class=unimportant>%s</span>\n",
 			"", valueOrDot(flat, rpt), valueOrDot(cum, rpt), an.address,
@@ -772,7 +857,7 @@ func printFunctionSourceLine(w io.Writer, lineNo int, flat, cum int64, lineConte
 			// would cause double-escaping of file name.
 			fileline)
 	}
-	fmt.Fprintln(w, "</span>")
+	fmt.Fprint(w, "</span>")
 }
 
 // printFunctionClosing prints the end of a function in a weblist report.
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/source_html.go b/src/cmd/vendor/github.com/google/pprof/internal/report/source_html.go
index 26e8bdbba8..17c9f6eb94 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/report/source_html.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/source_html.go
@@ -40,14 +40,7 @@ h1 {
 .inlinesrc {
   color: #000066;
 }
-.deadsrc {
-cursor: pointer;
-}
-.deadsrc:hover {
-background-color: #eeeeee;
-}
 .livesrc {
-color: #0000ff;
 cursor: pointer;
 }
 .livesrc:hover {
diff --git a/src/cmd/vendor/github.com/google/pprof/internal/report/synth.go b/src/cmd/vendor/github.com/google/pprof/internal/report/synth.go
new file mode 100644
index 0000000000..7a35bbcda8
--- /dev/null
+++ b/src/cmd/vendor/github.com/google/pprof/internal/report/synth.go
@@ -0,0 +1,39 @@
+package report
+
+import (
+	"github.com/google/pprof/profile"
+)
+
+// synthCode assigns addresses to locations without an address.
+type synthCode struct {
+	next uint64
+	addr map[*profile.Location]uint64 // Synthesized address assigned to a location
+}
+
+func newSynthCode(mappings []*profile.Mapping) *synthCode {
+	// Find a larger address than any mapping.
+	s := &synthCode{next: 1}
+	for _, m := range mappings {
+		if s.next < m.Limit {
+			s.next = m.Limit
+		}
+	}
+	return s
+}
+
+// address returns the synthetic address for loc, creating one if needed.
+func (s *synthCode) address(loc *profile.Location) uint64 {
+	if loc.Address != 0 {
+		panic("can only synthesize addresses for locations without an address")
+	}
+	if addr, ok := s.addr[loc]; ok {
+		return addr
+	}
+	if s.addr == nil {
+		s.addr = map[*profile.Location]uint64{}
+	}
+	addr := s.next
+	s.next++
+	s.addr[loc] = addr
+	return addr
+}
diff --git a/src/cmd/vendor/github.com/google/pprof/profile/encode.go b/src/cmd/vendor/github.com/google/pprof/profile/encode.go
index 1e84c72d43..ab7f03ae26 100644
--- a/src/cmd/vendor/github.com/google/pprof/profile/encode.go
+++ b/src/cmd/vendor/github.com/google/pprof/profile/encode.go
@@ -308,7 +308,7 @@ func (p *Profile) postDecode() error {
 			if l.strX != 0 {
 				value, err = getString(p.stringTable, &l.strX, err)
 				labels[key] = append(labels[key], value)
-			} else if l.numX != 0 {
+			} else if l.numX != 0 || l.unitX != 0 {
 				numValues := numLabels[key]
 				units := numUnits[key]
 				if l.unitX != 0 {
diff --git a/src/cmd/vendor/github.com/google/pprof/profile/merge.go b/src/cmd/vendor/github.com/google/pprof/profile/merge.go
index 5ab6e9b9b0..9978e7330e 100644
--- a/src/cmd/vendor/github.com/google/pprof/profile/merge.go
+++ b/src/cmd/vendor/github.com/google/pprof/profile/merge.go
@@ -231,7 +231,6 @@ func (pm *profileMerger) mapLocation(src *Location) *Location {
 	}
 
 	if l, ok := pm.locationsByID[src.ID]; ok {
-		pm.locationsByID[src.ID] = l
 		return l
 	}
 
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 6b19ec3aea..5fb1c25ace 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -1,4 +1,4 @@
-# github.com/google/pprof v0.0.0-20210226084205-cbba55b83ad5
+# github.com/google/pprof v0.0.0-20210506205249-923b5ab0fc1a
 ## explicit; go 1.14
 github.com/google/pprof/driver
 github.com/google/pprof/internal/binutils