From 32bdd19f8fa1e9a3b44a84191ad75cb2c4897fcd Mon Sep 17 00:00:00 2001
From: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Date: Tue, 17 May 2022 18:19:34 +0200
Subject: [PATCH] proc/gdbserver: fix function call injection on rr (#3007)

Issue https://github.com/rr-debugger/rr/issues/3208 was fixed so finish
fixing call injection on rr and remove the test exception.
---
 pkg/proc/gdbserial/gdbserver.go | 66 +++++++++++++++++++++++++--------
 pkg/proc/proc_test.go           |  1 +
 service/test/variables_test.go  |  5 ---
 3 files changed, 51 insertions(+), 21 deletions(-)

diff --git a/pkg/proc/gdbserial/gdbserver.go b/pkg/proc/gdbserial/gdbserver.go
index aafca0c5..7c0ca13f 100644
--- a/pkg/proc/gdbserial/gdbserver.go
+++ b/pkg/proc/gdbserial/gdbserver.go
@@ -1958,27 +1958,61 @@ func (t *gdbThread) SetReg(regNum uint64, reg *op.DwarfRegister) error {
 	if !ok && t.p.bi.Arch.Name == "arm64" && regName == "x30" {
 		gdbreg, ok = t.regs.regs["lr"]
 	}
+	if !ok && regName == "rflags" {
+		// rr has eflags instead of rflags
+		regName = "eflags"
+		gdbreg, ok = t.regs.regs[regName]
+		if ok {
+			reg.FillBytes()
+			reg.Bytes = reg.Bytes[:4]
+		}
+	}
 	if !ok {
 		return fmt.Errorf("could not set register %s: not found", regName)
 	}
 	reg.FillBytes()
-	if len(reg.Bytes) != len(gdbreg.value) {
-		return fmt.Errorf("could not set register %s: wrong size, expected %d got %d", regName, len(gdbreg.value), len(reg.Bytes))
+
+	wrongSizeErr := func(n int) error {
+		return fmt.Errorf("could not set register %s: wrong size, expected %d got %d", regName, n, len(reg.Bytes))
 	}
-	copy(gdbreg.value, reg.Bytes)
-	err := t.p.conn.writeRegister(t.strID, gdbreg.regnum, gdbreg.value)
-	if err != nil {
-		return err
-	}
-	if t.p.conn.workaroundReg != nil && len(gdbreg.value) > 16 {
-		// This is a workaround for a bug in debugserver where register writes (P
-		// packet) on AVX-2 and AVX-512 registers are ignored unless they are
-		// followed by a write to an AVX register.
-		// See:
-		//  Issue #2767
-		//  https://bugs.llvm.org/show_bug.cgi?id=52362
-		reg := t.regs.gdbRegisterNew(t.p.conn.workaroundReg)
-		return t.p.conn.writeRegister(t.strID, reg.regnum, reg.value)
+
+	if len(reg.Bytes) == len(gdbreg.value) {
+		copy(gdbreg.value, reg.Bytes)
+		err := t.p.conn.writeRegister(t.strID, gdbreg.regnum, gdbreg.value)
+		if err != nil {
+			return err
+		}
+		if t.p.conn.workaroundReg != nil && len(gdbreg.value) > 16 {
+			// This is a workaround for a bug in debugserver where register writes (P
+			// packet) on AVX-2 and AVX-512 registers are ignored unless they are
+			// followed by a write to an AVX register.
+			// See:
+			//  Issue #2767
+			//  https://bugs.llvm.org/show_bug.cgi?id=52362
+			reg := t.regs.gdbRegisterNew(t.p.conn.workaroundReg)
+			return t.p.conn.writeRegister(t.strID, reg.regnum, reg.value)
+		}
+	} else if len(reg.Bytes) == 2*len(gdbreg.value) && strings.HasPrefix(regName, "xmm") {
+		// rr uses xmmN for the low part of the register and ymmNh for the high part
+		gdbregh, ok := t.regs.regs["y"+regName[1:]+"h"]
+		if !ok {
+			return wrongSizeErr(len(gdbreg.value))
+		}
+		if len(reg.Bytes) != len(gdbreg.value)+len(gdbregh.value) {
+			return wrongSizeErr(len(gdbreg.value) + len(gdbregh.value))
+		}
+		copy(gdbreg.value, reg.Bytes[:len(gdbreg.value)])
+		copy(gdbregh.value, reg.Bytes[len(gdbreg.value):])
+		err := t.p.conn.writeRegister(t.strID, gdbreg.regnum, gdbreg.value)
+		if err != nil {
+			return err
+		}
+		err = t.p.conn.writeRegister(t.strID, gdbregh.regnum, gdbregh.value)
+		if err != nil {
+			return err
+		}
+	} else {
+		return wrongSizeErr(len(gdbreg.value))
 	}
 	return nil
 }
diff --git a/pkg/proc/proc_test.go b/pkg/proc/proc_test.go
index 0a74ac2a..f156a6f1 100644
--- a/pkg/proc/proc_test.go
+++ b/pkg/proc/proc_test.go
@@ -5860,6 +5860,7 @@ func TestCallInjectionFlagCorruption(t *testing.T) {
 	// time, after stepping out of debugCallV2.
 	// Fixes issue https://github.com/go-delve/delve/issues/2985
 	skipUnlessOn(t, "not relevant", "amd64")
+	protest.MustSupportFunctionCalls(t, testBackend)
 
 	withTestProcessArgs("badflags", t, ".", []string{"0"}, 0, func(p *proc.Target, fixture protest.Fixture) {
 		mainfn := p.BinInfo().LookupFunc["main.main"]
diff --git a/service/test/variables_test.go b/service/test/variables_test.go
index c8c4a7d0..6a83c397 100644
--- a/service/test/variables_test.go
+++ b/service/test/variables_test.go
@@ -1340,11 +1340,6 @@ func TestCallFunction(t *testing.T) {
 
 		if goversion.VersionAfterOrEqual(runtime.Version(), 1, 17) {
 			for _, tc := range testcases117 {
-				if strings.Contains(tc.expr, "floatsum") && testBackend == "rr" {
-					// Can not set floating point registers with RR.
-					// See: https://github.com/rr-debugger/rr/issues/3208
-					continue
-				}
 				testCallFunction(t, p, tc)
 			}
 		}