cmd: update vendored pprof

  go get github.com/google/pprof@latest
  go mod vendor

Plus a tiny change to the pprof command to match an upstream interface
change.

Updates #36905.

Change-Id: I4c7bbe8c317a6eeb217fce971b208f96ab0727fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/393370
Trust: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
Auto-Submit: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

1 files changed, 23 insertions, 15 deletions

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 e920eeb2fa..efa9167af7 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
@@ -284,7 +284,7 @@ func (bu *Binutils) Disasm(file string, start, end uint64, intelSyntax bool) ([]
 }
 
 // Open satisfies the plugin.ObjTool interface.
-func (bu *Binutils) Open(name string, start, limit, offset uint64) (plugin.ObjFile, error) {
+func (bu *Binutils) Open(name string, start, limit, offset uint64, relocationSymbol string) (plugin.ObjFile, error) {
 	b := bu.get()
 
 	// Make sure file is a supported executable.
@@ -316,7 +316,7 @@ func (bu *Binutils) Open(name string, start, limit, offset uint64) (plugin.ObjFi
 
 	// Match against supported file types.
 	if elfMagic == elf.ELFMAG {
-		f, err := b.openELF(name, start, limit, offset)
+		f, err := b.openELF(name, start, limit, offset, relocationSymbol)
 		if err != nil {
 			return nil, fmt.Errorf("error reading ELF file %s: %v", name, err)
 		}
@@ -425,7 +425,7 @@ func (b *binrep) openMachO(name string, start, limit, offset uint64) (plugin.Obj
 	return b.openMachOCommon(name, of, start, limit, offset)
 }
 
-func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFile, error) {
+func (b *binrep) openELF(name string, start, limit, offset uint64, relocationSymbol string) (plugin.ObjFile, error) {
 	ef, err := elfOpen(name)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing %s: %v", name, err)
@@ -440,8 +440,8 @@ func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFi
 	}
 
 	var (
-		stextOffset *uint64
-		pageAligned = func(addr uint64) bool { return addr%4096 == 0 }
+		kernelOffset *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
@@ -455,10 +455,18 @@ func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFi
 		if err != nil && err != elf.ErrNoSymbols {
 			return nil, err
 		}
+
+		// The kernel relocation symbol (the mapping start address) can be either
+		// _text or _stext. When profiles are generated by `perf`, which one was used is
+		// distinguished by the mapping name for the kernel image:
+		// '[kernel.kallsyms]_text' or '[kernel.kallsyms]_stext', respectively. If we haven't
+		// been able to parse it from the mapping, we default to _stext.
+		if relocationSymbol == "" {
+			relocationSymbol = "_stext"
+		}
 		for _, s := range symbols {
-			if s.Name == "_stext" {
-				// The kernel may use _stext as the mapping start address.
-				stextOffset = &s.Value
+			if s.Name == relocationSymbol {
+				kernelOffset = &s.Value
 				break
 			}
 		}
@@ -469,7 +477,7 @@ func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFi
 	// 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 {
+	if _, err := elfexec.GetBase(&ef.FileHeader, elfexec.FindTextProgHeader(ef), kernelOffset, start, limit, offset); err != nil {
 		return nil, fmt.Errorf("could not identify base for %s: %v", name, err)
 	}
 
@@ -478,14 +486,14 @@ func (b *binrep) openELF(name string, start, limit, offset uint64) (plugin.ObjFi
 			b:       b,
 			name:    name,
 			buildID: buildID,
-			m:       &elfMapping{start: start, limit: limit, offset: offset, stextOffset: stextOffset},
+			m:       &elfMapping{start: start, limit: limit, offset: offset, kernelOffset: kernelOffset},
 		}}, nil
 	}
 	return &fileAddr2Line{file: file{
 		b:       b,
 		name:    name,
 		buildID: buildID,
-		m:       &elfMapping{start: start, limit: limit, offset: offset, stextOffset: stextOffset},
+		m:       &elfMapping{start: start, limit: limit, offset: offset, kernelOffset: kernelOffset},
 	}}, nil
 }
 
@@ -521,8 +529,8 @@ func (b *binrep) openPE(name string, start, limit, offset uint64) (plugin.ObjFil
 type elfMapping struct {
 	// Runtime mapping parameters.
 	start, limit, offset uint64
-	// Offset of _stext symbol. Only defined for kernel images, nil otherwise.
-	stextOffset *uint64
+	// Offset of kernel relocation symbol. Only defined for kernel images, nil otherwise.
+	kernelOffset *uint64
 }
 
 // findProgramHeader returns the program segment that matches the current
@@ -535,7 +543,7 @@ func (m *elfMapping) findProgramHeader(ef *elf.File, addr uint64) (*elf.ProgHead
 	// 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 m.stextOffset != nil || m.start >= m.limit || m.limit >= (uint64(1)<<63) {
+	if m.kernelOffset != nil || m.start >= m.limit || m.limit >= (uint64(1)<<63) {
 		// For the kernel, find the program segment that includes the .text section.
 		return elfexec.FindTextProgHeader(ef), nil
 	}
@@ -601,7 +609,7 @@ func (f *file) computeBase(addr uint64) error {
 		return fmt.Errorf("failed to find program header for file %q, ELF mapping %#v, address %x: %v", f.name, *f.m, addr, err)
 	}
 
-	base, err := elfexec.GetBase(&ef.FileHeader, ph, f.m.stextOffset, f.m.start, f.m.limit, f.m.offset)
+	base, err := elfexec.GetBase(&ef.FileHeader, ph, f.m.kernelOffset, f.m.start, f.m.limit, f.m.offset)
 	if err != nil {
 		return err
 	}