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Support immediate binding option #335

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b66e716
Implement immediate binding for dynamic linking
DrXiao Sep 9, 2026
6349b32
Introduce a Makefile variable to determine the binding strategy
DrXiao Sep 9, 2026
3c3998d
Improve test suites to validate immediate binding mode
DrXiao Sep 15, 2026
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13 changes: 7 additions & 6 deletions Makefile
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Original file line number Diff line number Diff line change
Expand Up @@ -53,12 +53,13 @@ BUILTIN_LIBC_HEADER := c.h
STAGE0_FLAGS ?= --dump-ir
STAGE1_FLAGS ?=
DYNLINK ?= 0
BINDING ?= lazy

COMMENTFLOW ?= commentflow
SHFMT ?= shfmt
ifeq ($(DYNLINK),1)
STAGE0_FLAGS += --dynlink
STAGE1_FLAGS += --dynlink
STAGE0_FLAGS += --dynlink -z $(BINDING)
STAGE1_FLAGS += --dynlink -z $(BINDING)
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cubic-dev-ai[bot] marked this conversation as resolved.
endif

SRCS := $(wildcard $(patsubst %,%/main.c, $(SRCDIR)))
Expand Down Expand Up @@ -183,11 +184,11 @@ uninstall-hooks:

check-stage0: $(OUT)/$(STAGE0) tests/driver.sh
$(VECHO) " TEST STAGE 0\n"
tests/driver.sh 0 $(DYNLINK)
tests/driver.sh 0 $(DYNLINK) $(BINDING)

check-stage2: $(OUT)/$(STAGE2) tests/driver.sh
$(VECHO) " TEST STAGE 2\n"
tests/driver.sh 2 $(DYNLINK)
tests/driver.sh 2 $(DYNLINK) $(BINDING)

check-sanitizer: $(OUT)/$(STAGE0)-sanitizer tests/driver.sh
$(VECHO) " TEST STAGE 0 (with sanitizers)\n"
Expand All @@ -196,10 +197,10 @@ check-sanitizer: $(OUT)/$(STAGE0)-sanitizer tests/driver.sh
$(Q)rm $(OUT)/shecc

check-abi-stage0: $(OUT)/$(STAGE0)
tests/$(ARCH)-abi.sh 0 $(DYNLINK);
tests/$(ARCH)-abi.sh 0 $(DYNLINK) $(BINDING);

check-abi-stage2: $(OUT)/$(STAGE2)
tests/$(ARCH)-abi.sh 2 $(DYNLINK);
tests/$(ARCH)-abi.sh 2 $(DYNLINK) $(BINDING);

# Both prerequisites are order-only, and both exist because "make -j" would
# otherwise let a compile start beside the thing it reads. Selecting a target
Expand Down
1 change: 0 additions & 1 deletion mk/arm64.mk
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Expand Up @@ -25,7 +25,6 @@ ARCH_DEFS = \
\#define PLT_ENT_SIZE 16\n$\
\#define RESERVED_GOT_NUM 3\n$\
\#define R_ARCH_JUMP_SLOT 1026 /* R_AARCH64_JUMP_SLOT */\n$\
\#define DYN_BIND_NOW 1\n$\
"

# An Arm64 Linux host runs this target's output itself, so nothing has to stand
Expand Down
1 change: 0 additions & 1 deletion mk/x64.mk
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Expand Up @@ -16,7 +16,6 @@ ARCH_DEFS = \
\#define RESERVED_GOT_NUM 3\n$\
\#define R_ARCH_JUMP_SLOT 7 /* R_X86_64_JUMP_SLOT */\n$\
\#define REG_CNT 11 /* rdi rsi rdx rcx r8 r9 rax rbx r14 r12 r13 */\n$\
\#define DYN_BIND_NOW 1 /* this PLT has no lazy-resolution path */\n$\
\#define HAVE_COND_MOVE 1 /* CMOVcc */\n$\
\#define CALLEE_SAVED_REGS 4 /* the file ends rbx r14 r12 r13 */\n$\
"
7 changes: 0 additions & 7 deletions src/defs.h
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Expand Up @@ -177,13 +177,6 @@
#define ALIGN_UP(val, align) (((val) + (align) - 1) & ~((align) - 1))
#endif

/* Targets whose PLT has no lazy-resolution path ask the loader to bind every
* PLT entry at load time.
*/
#ifndef DYN_BIND_NOW
#define DYN_BIND_NOW 0
#endif

#define ELF_MACHINE_ARM32 0x28
#define ELF_MACHINE_RV32 0xf3
#define ELF_MACHINE_X86_64 0x3e
Expand Down
11 changes: 7 additions & 4 deletions src/elf.c
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Expand Up @@ -1086,14 +1086,17 @@ void elf_generate_dynamic_sections(void)
elf_write_dyn(dynamic_sections.elf_dynamic, 0x3,
dynamic_sections.elf_got_start);
elf_write_dyn(dynamic_sections.elf_dynamic, 0x1, 0x1);
#if DYN_BIND_NOW == 1

/* Resolve every PLT entry at load time. This target's PLT[0] does not
* arrange the GOT[1]/GOT[2] hand-off the lazy resolver needs, so the loader
* writes the final addresses straight into the GOT instead.
*/
elf_write_dyn(dynamic_sections.elf_dynamic, 0x18, 0x0); /* DT_BIND_NOW */
elf_write_dyn(dynamic_sections.elf_dynamic, 0x1e, 0x8); /* DF_BIND_NOW */
#endif
if (imm_binding) {
elf_write_dyn(dynamic_sections.elf_dynamic, 0x18,
0x0); /* DT_BIND_NOW */
elf_write_dyn(dynamic_sections.elf_dynamic, 0x1e,
0x8); /* DF_BIND_NOW */
}
elf_write_dyn(dynamic_sections.elf_dynamic, 0x0, 0x0);
}

Expand Down
1 change: 1 addition & 0 deletions src/globals.c
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Expand Up @@ -101,6 +101,7 @@ dynamic_sections_t dynamic_sections;

/* Command line compilation flags */
bool dynlink = false;
bool imm_binding = false;
bool libc = true;
bool expand_only = false;
bool dump_ir = false;
Expand Down
26 changes: 24 additions & 2 deletions src/main.c
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Expand Up @@ -117,7 +117,18 @@ int main(int argc, char *argv[])
libc = false;
else if (!strcmp(argv[i], "--dynlink"))
dynlink = true;
else if (!strcmp(argv[i], "-E"))
else if (!strcmp(argv[i], "-z")) {
if (i + 1 >= argc)
usage_error("-z requires \"lazy\" or \"now\"");

if (!strcmp(argv[i + 1], "lazy"))
imm_binding = false;
else if (!strcmp(argv[i + 1], "now"))
imm_binding = true;
else
usage_error("-z requires \"lazy\" or \"now\"");
i++;
} else if (!strcmp(argv[i], "-E"))
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cubic-dev-ai[bot] marked this conversation as resolved.
expand_only = true;
else if (!strcmp(argv[i], "-o")) {
if (i + 1 < argc) {
Expand All @@ -131,10 +142,21 @@ int main(int argc, char *argv[])
in = argv[i];
}

if (dynlink) {
switch (ELF_MACHINE) {
/* The following 64-bit targets have no lazy-resolution path, so
* immediate binding must be used.
*/
case ELF_MACHINE_X86_64:
case ELF_MACHINE_AARCH64:
imm_binding = true;
}
}

if (!in) {
printf(
"Usage: shecc [-o output] [+m] [--dot] [--dump-ir] [--no-libc] "
"[--dynlink] [-E] <input.c>\n");
"[--dynlink] [-z <lazy | now>] [-E] <input.c>\n");
usage_error("Missing source file");
}

Expand Down
6 changes: 4 additions & 2 deletions tests/arm-abi.sh
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Expand Up @@ -41,9 +41,10 @@ fi

# Command Line Arguments
if [ "$#" -lt 1 ]; then
echo "Usage: $0 <stage> [<dynlink>]"
echo "Usage: $0 <stage> [<dynlink> [<binding>]]"
echo " stage: 0 (host compiler), 1 (stage1), or 2 (stage2)"
echo " dynlink: 0 (static linking), 1 (dynamic linking)"
echo " binding: lazy, now"
echo ""
echo "Environment Variables:"
echo " VERBOSE=1 Enable verbose output"
Expand Down Expand Up @@ -73,6 +74,7 @@ case "$1" in
esac

DYNLINK="${2:-0}"
BINDING="${3:-lazy}"

# Banner
echo -e "${BLUE}${BOLD}========================================${NC}"
Expand Down Expand Up @@ -144,7 +146,7 @@ run_abi_test()
# Compile
local compile_cmd="$SHECC"
if [[ "$DYNLINK" == "1" ]]; then
compile_cmd="$compile_cmd --dynlink"
compile_cmd="$compile_cmd --dynlink -z $BINDING"

@cubic-dev-ai cubic-dev-ai Bot Sep 15, 2026

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P2: When the binding argument contains shell syntax, this line inserts it into an eval string, so the ABI test executes it as a separate command. Escape the value or execute the compiler through an argv array.

Prompt for AI agents 
Check if this issue is valid — if so, understand the root cause and fix it. At tests/arm-abi.sh, line 149:

<comment>When the binding argument contains shell syntax, this line inserts it into an `eval` string, so the ABI test executes it as a separate command. Escape the value or execute the compiler through an argv array.</comment>

<file context>
@@ -144,7 +146,7 @@ run_abi_test()
     local compile_cmd="$SHECC"
     if [[ "$DYNLINK" == "1" ]]; then
-        compile_cmd="$compile_cmd --dynlink"
+        compile_cmd="$compile_cmd --dynlink -z $BINDING"
     fi
     compile_cmd="$compile_cmd -o /tmp/shecc_abi_test_$$.elf $test_file"
</file context>
Suggested change
compile_cmd="$compile_cmd --dynlink -z $BINDING"
compile_cmd="$compile_cmd --dynlink -z $(printf '%q' "$BINDING")"

fi
compile_cmd="$compile_cmd -o /tmp/shecc_abi_test_$$.elf $test_file"

Expand Down
4 changes: 2 additions & 2 deletions tests/arm64-abi.sh
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Expand Up @@ -4,7 +4,7 @@
set -eu

if [ "$#" -lt 1 ]; then
echo "Usage: $0 <stage> [<dynlink>]" >&2
echo "Usage: $0 <stage> [<dynlink> [<binding>]]" >&2
exit 2
fi

Expand All @@ -23,7 +23,7 @@ case "$1" in
esac

if [ "${2:-0}" = 1 ]; then
shecc+=(--dynlink)
shecc+=(--dynlink -z "${3:-lazy}")
link_mode=dynamic
else
link_mode=static
Expand Down
2 changes: 1 addition & 1 deletion tests/driver.sh
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Expand Up @@ -106,7 +106,7 @@ case "$1" in
esac

if [ $# -ge 2 ] && [ "$2" = "1" ]; then
readonly SHECC_CFLAGS="--dynlink"
readonly SHECC_CFLAGS="--dynlink ${3:-lazy}"
readonly LINK_MODE="dynamic"
else
readonly SHECC_CFLAGS=""
Expand Down
6 changes: 4 additions & 2 deletions tests/riscv-abi.sh
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Expand Up @@ -41,9 +41,10 @@ fi

# Command Line Arguments
if [ "$#" -lt 1 ]; then
echo "Usage: $0 <stage> [<dynlink>]"
echo "Usage: $0 <stage> [<dynlink> [<binding>]]"
echo " stage: 0 (host compiler), 1 (stage1), or 2 (stage2)"
echo " dynlink: 0 (static linking), 1 (dynamic linking)"
echo " binding: lazy, now"
echo ""
echo "Environment Variables:"
echo " VERBOSE=1 Enable verbose output"
Expand Down Expand Up @@ -73,6 +74,7 @@ case "$1" in
esac

DYNLINK="${2:-0}"
BINDING="${3:-lazy}"

# Banner
echo -e "${BLUE}${BOLD}========================================${NC}"
Expand Down Expand Up @@ -144,7 +146,7 @@ run_abi_test()
# Compile
local compile_cmd="$SHECC"
if [[ "$DYNLINK" == "1" ]]; then
compile_cmd="$compile_cmd --dynlink"
compile_cmd="$compile_cmd --dynlink -z $BINDING"

@cubic-dev-ai cubic-dev-ai Bot Sep 15, 2026

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P2: An unvalidated binding argument is inserted into a command string executed by eval, so invoking this test script with a crafted third argument executes arbitrary shell commands. Validate the value against lazy|now or shell-escape it before constructing the command.

Prompt for AI agents 
Check if this issue is valid — if so, understand the root cause and fix it. At tests/riscv-abi.sh, line 149:

<comment>An unvalidated `binding` argument is inserted into a command string executed by `eval`, so invoking this test script with a crafted third argument executes arbitrary shell commands. Validate the value against `lazy|now` or shell-escape it before constructing the command.</comment>

<file context>
@@ -144,7 +146,7 @@ run_abi_test()
     local compile_cmd="$SHECC"
     if [[ "$DYNLINK" == "1" ]]; then
-        compile_cmd="$compile_cmd --dynlink"
+        compile_cmd="$compile_cmd --dynlink -z $BINDING"
     fi
     compile_cmd="$compile_cmd -o /tmp/shecc_abi_test_$$.elf $test_file"
</file context>
Suggested change
compile_cmd="$compile_cmd --dynlink -z $BINDING"
compile_cmd="$compile_cmd --dynlink -z $(printf '%q' "$BINDING")"

fi
compile_cmd="$compile_cmd -o /tmp/shecc_abi_test_$$.elf $test_file"

Expand Down
6 changes: 4 additions & 2 deletions tests/x64-abi.sh
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Expand Up @@ -42,9 +42,10 @@ fi

# Command Line Arguments
if [ "$#" -lt 1 ]; then
echo "Usage: $0 <stage> [<dynlink>]"
echo "Usage: $0 <stage> [<dynlink> [<binding>]]"
echo " stage: 0 (host compiler), 1 (stage1), or 2 (stage2)"
echo " dynlink: 0 (static linking), 1 (dynamic linking)"
echo " binding: lazy, now"
echo ""
echo "Environment Variables:"
echo " VERBOSE=1 Enable verbose output"
Expand Down Expand Up @@ -74,6 +75,7 @@ case "$1" in
esac

DYNLINK="${2:-0}"
BINDING="${3:-lazy}"

# Banner
echo -e "${BLUE}${BOLD}========================================${NC}"
Expand Down Expand Up @@ -149,7 +151,7 @@ run_abi_test()
# Compile
local compile_cmd="$SHECC"
if [[ "$DYNLINK" == "1" ]]; then
compile_cmd="$compile_cmd --dynlink"
compile_cmd="$compile_cmd --dynlink -z $BINDING"
fi
compile_cmd="$compile_cmd -o /tmp/shecc_abi_test_$$.elf $test_file"

Expand Down