Revert "cmd/vendor/.../pprof: refresh from upstream@a74ae6f"

This reverts commit c6e69ec7f930191022f1369761a680eecc2e89f1.

Reason for revert: Broke builders. #24508

Change-Id: I66abff0dd14ec6e1f8d8d982ccfb0438633b639d
Reviewed-on: https://go-review.googlesource.com/102316
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

1 files changed, 9 insertions, 16 deletions

diff --git a/src/cmd/vendor/github.com/google/pprof/internal/binutils/addr2liner.go b/src/cmd/vendor/github.com/google/pprof/internal/binutils/addr2liner.go
index c0661bf4aa..71e471b5d6 100644
--- a/src/cmd/vendor/github.com/google/pprof/internal/binutils/addr2liner.go
+++ b/src/cmd/vendor/github.com/google/pprof/internal/binutils/addr2liner.go
@@ -41,11 +41,9 @@ type addr2Liner struct {
 	rw   lineReaderWriter
 	base uint64
 
-	// nm holds an addr2Liner using nm tool. Certain versions of addr2line
-	// produce incomplete names due to
-	// https://sourceware.org/bugzilla/show_bug.cgi?id=17541. As a workaround,
-	// the names from nm are used when they look more complete. See addrInfo()
-	// code below for the exact heuristic.
+	// nm holds an NM based addr2Liner which can provide
+	// better full names compared to addr2line, which often drops
+	// namespaces etc. from the names it returns.
 	nm *addr2LinerNM
 }
 
@@ -217,22 +215,17 @@ func (d *addr2Liner) addrInfo(addr uint64) ([]plugin.Frame, error) {
 		return nil, err
 	}
 
-	// Certain versions of addr2line produce incomplete names due to
-	// https://sourceware.org/bugzilla/show_bug.cgi?id=17541. Attempt to replace
-	// the name with a better one from nm.
+	// Get better name from nm if possible.
 	if len(stack) > 0 && d.nm != nil {
 		nm, err := d.nm.addrInfo(addr)
 		if err == nil && len(nm) > 0 {
-			// Last entry in frame list should match since it is non-inlined. As a
-			// simple heuristic, we only switch to the nm-based name if it is longer
-			// by 2 or more characters. We consider nm names that are longer by 1
-			// character insignificant to avoid replacing foo with _foo on MacOS (for
-			// unknown reasons read2line produces the former and nm produces the
-			// latter on MacOS even though both tools are asked to produce mangled
-			// names).
+			// Last entry in frame list should match since
+			// it is non-inlined. As a simple heuristic,
+			// we only switch to the nm-based name if it
+			// is longer.
 			nmName := nm[len(nm)-1].Func
 			a2lName := stack[len(stack)-1].Func
-			if len(nmName) > len(a2lName)+1 {
+			if len(nmName) > len(a2lName) {
 				stack[len(stack)-1].Func = nmName
 			}
 		}