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[v2,dwarves,4/9] btf_encoder: make the variable array dynamic

Message ID 20221104231103.752040-5-stephen.s.brennan@oracle.com (mailing list archive)
State Not Applicable
Delegated to: BPF
Headers show
Series Add support for generating BTF for all variables | expand

Checks

Context Check Description
netdev/tree_selection success Not a local patch
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Commit Message

Stephen Brennan Nov. 4, 2022, 11:10 p.m. UTC 
To collect all variables, we need a dynamically allocated array to scale
with any amount.

Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
---
 btf_encoder.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/btf_encoder.c b/btf_encoder.c
index e0e038b..5cd247d 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -37,7 +37,6 @@  struct elf_function {
 	bool		 generated;
 };
 
-#define MAX_VAR_CNT 4096
 #define MAX_ELF_SEC_CNT    128
 
 struct var_info {
@@ -75,8 +74,9 @@  struct btf_encoder {
 	struct elf_secinfo secinfo[MAX_ELF_SEC_CNT];
 	size_t		  seccnt;
 	struct {
-		struct var_info vars[MAX_VAR_CNT];
+		struct var_info *vars;
 		int		var_cnt;
+		int		var_alloc;
 		uint32_t	percpu_shndx;
 	} variables;
 	struct {
@@ -1206,6 +1206,15 @@  static int btf_encoder__collect_percpu_var(struct btf_encoder *encoder, GElf_Sym
 	if (elf_sym__type(sym) != STT_OBJECT)
 		return 0;
 
+	if (encoder->variables.var_cnt == encoder->variables.var_alloc) {
+		struct var_info *new;
+		encoder->variables.var_alloc = max(1000, encoder->variables.var_alloc * 3 / 2);
+		new = realloc(encoder->variables.vars, encoder->variables.var_alloc * sizeof(*new));
+		if (!new)
+			return -1;
+		encoder->variables.vars = new;
+	}
+
 	addr = elf_sym__value(sym);
 
 	size = elf_sym__size(sym);
@@ -1232,11 +1241,6 @@  static int btf_encoder__collect_percpu_var(struct btf_encoder *encoder, GElf_Sym
 		addr += encoder->secinfo[sym->st_shndx].addr;
 	}
 
-	if (encoder->variables.var_cnt == MAX_VAR_CNT) {
-		fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
-			MAX_VAR_CNT);
-		return -1;
-	}
 	encoder->variables.vars[encoder->variables.var_cnt].addr = addr;
 	encoder->variables.vars[encoder->variables.var_cnt].sz = size;
 	encoder->variables.vars[encoder->variables.var_cnt].name = sym_name;
@@ -1520,6 +1524,10 @@  void btf_encoder__delete(struct btf_encoder *encoder)
 	encoder->btf = NULL;
 	elf_symtab__delete(encoder->symtab);
 
+	encoder->variables.var_cnt = encoder->variables.var_alloc = 0;
+	free(encoder->variables.vars);
+	encoder->variables.vars = NULL;
+
 	encoder->functions.allocated = encoder->functions.cnt = 0;
 	free(encoder->functions.entries);
 	encoder->functions.entries = NULL;