From: Derek Parker <parkerderek86@gmail.com>
Date: Fri, 21 Mar 2025 19:43:32 +0000 (+0000)
Subject: cmd/compile/internal/abi: fix ComputePadding
X-Git-Tag: go1.25rc1~630
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=afe11db4a7d61d6ec196577f39b45648f987927d;p=gostls13.git

cmd/compile/internal/abi: fix ComputePadding

Fixes the ComputePadding calculation to take into account the padding
added for the current offset. This fixes an issue where padding can be
added incorrectly for certain structs.

Related: https://github.com/go-delve/delve/issues/3923

Same as https://go-review.googlesource.com/c/go/+/656736 just without
the brittle test.

Fixes #72053

Change-Id: I67f157a42f5fc5d3a54d0e9be03488aa44752bcb
GitHub-Last-Rev: fabed69a31258fa8c1806f88d1cbcc745c881148
GitHub-Pull-Request: golang/go#72997
Reviewed-on: https://go-review.googlesource.com/c/go/+/659698
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---

diff --git a/src/cmd/compile/internal/abi/abiutils.go b/src/cmd/compile/internal/abi/abiutils.go
index e88a80d564..c013aba19c 100644
--- a/src/cmd/compile/internal/abi/abiutils.go
+++ b/src/cmd/compile/internal/abi/abiutils.go
@@ -673,10 +673,9 @@ func (pa *ABIParamAssignment) ComputePadding(storage []uint64) []uint64 {
 		panic("internal error")
 	}
 	offsets, _ := appendParamOffsets([]int64{}, 0, pa.Type)
-	off := int64(0)
 	for idx, t := range types {
 		ts := t.Size()
-		off += int64(ts)
+		off := offsets[idx] + ts
 		if idx < len(types)-1 {
 			noff := offsets[idx+1]
 			if noff != off {
diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go
index 59d0294264..6faef7c255 100644
--- a/src/cmd/compile/internal/ssa/debug.go
+++ b/src/cmd/compile/internal/ssa/debug.go
@@ -557,7 +557,7 @@ func PopulateABIInRegArgOps(f *Func) {
 	f.Entry.Values = append(newValues, f.Entry.Values...)
 }
 
-// BuildFuncDebug debug information for f, placing the results
+// BuildFuncDebug builds debug information for f, placing the results
 // in "rval". f must be fully processed, so that each Value is where it
 // will be when machine code is emitted.
 func BuildFuncDebug(ctxt *obj.Link, f *Func, loggingLevel int, stackOffset func(LocalSlot) int32, rval *FuncDebug) {
diff --git a/src/cmd/compile/internal/test/abiutils_test.go b/src/cmd/compile/internal/test/abiutils_test.go
index b500de9f18..da807f5a0a 100644
--- a/src/cmd/compile/internal/test/abiutils_test.go
+++ b/src/cmd/compile/internal/test/abiutils_test.go
@@ -390,9 +390,9 @@ func TestABIUtilsComputePadding(t *testing.T) {
 	padding := make([]uint64, 32)
 	parm := regRes.InParams()[1]
 	padding = parm.ComputePadding(padding)
-	want := "[1 1 1 0]"
+	want := "[1 0 0 0]"
 	got := fmt.Sprintf("%+v", padding)
 	if got != want {
-		t.Errorf("padding mismatch: wanted %q got %q\n", got, want)
+		t.Errorf("padding mismatch: wanted %q got %q\n", want, got)
 	}
 }